Browsing by Author "Punchihewa, HKG"

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item: Conference-Full-text
An analysis of the current status of the footwear industry in Sri Lanka
(2005) Fernando, WMTPJ; Jayathilake, HPEU; Mahindaratne, PDPY; Punchihewa, HKG
Footwear industry in Sri Lanka has survived for a long period of time and this industry has successfully catered the local market till the early 90's, but in the recent past, this industry has been seriously affected by dumping of footwear products from East Asian countries, especially from China. Another reason for this is lack of proper planning. It is believed that the local footwear industry is capable of even exploring an international market. It might have a huge potential especially in the western countries as fashion oriented designer-wear, but this industry has not acquired enough attention of the relevant parties. It should be noted that the involvement of engineering know-how in the footwear industry is minimal. Although, there is some minute engineering involvement, the technology transfer to the footwear industry is negligible compared with the global arena. Firstly, no proper research has been carried out focussing on the problems related to the footwear industry in recent years in Sri Lanka. Secondly, the present situation with respect to the footwear industry has not been systematically evaluated by any organization or individual. Finally, most of the footwear manufacturing firms are carrying out their businesses individually, thinking that this prowess is unique to individual businesses. This was identified during the data collection phase of this research. Therefore, there is a necessity for comprehensive research, which is highly demanded by the industry and, that would be beneficial to all stakeholders of this industry at large. This work focuses on the issues discussed above and proposes a classification as well as general recommendations for the future advancement of the industry.
item: Thesis-Full-text
Analysis of the status of the rubber product manufacturing industry in Sri Lanka :
(2018) Dissanayake, MNCP; Punchihewa, HKG
The Sri Lankan rubber industry is currently experiencing burning problems. Mainly rubber industries are facing issues such as, low production, lack of cultivation area, low productivity, reduction of re-planting area and new planting area, decline trend of rubber prices, increase of cost of production, reduction of export of raw rubber, increase of domestic consumption and declined trend of exports earnings, lack of skilled labour. However no one has identified which factors are affecting to create these problems and also hardly to find any solution to the most important problems which are presently available in rubber industry. Therefore, this research is aiming to find most important barriers of rubber product industry and find out what they are and how to avoid or minimize those barriers. Objective of this survey was to gather information related to the present status of the rubber product industry in Sri Lanka and analyse the gathered information to propose the way forward in terms of barriers in the rubber products manufacturing sector. Survey was carried out by using questionnaires to find out the present situation, barriers, difficulties, issues, and solutions for rubber products industry. Large and medium scale rubber industries were targeted, and questionnaires were distributed according to the annual export performance (turnover) in each rubber products sectors. Gathered information from questionnaire was analysed by using PESTLE with Cobweb diagram, quantitative analysis, statistical analysis with linear correlation and qualitative analysis. During this survey, three major factors were identified which affect the rubber products industry, and they are Economic, Legal and Technological factors. Under above factors, identified several key barriers are Impact of globalization on market share, Effect of Health and Safety issues, Insufficient facilities for the development of technology in the organization, Lack of Research and Development activities compared to the Competitors, Lack of proper techniques to absorb international technology. Proposed several solutions are Free trade agreement with developed countries, Promote to follow (Occupational Safety and Health Standards) OSHS for rubber industry, Need free technology Alliance with developed countries, Need to increase budget allocation for R&D activities, Govt should provide facilities for Reverse Engineering. Extension of this survey to the small scale rubber industry is proposed as future work.
item: Thesis-Full-text
Analysis of weld shrinkage to obtain compensation factors for ship hull construction
Karunarathna, TA; Punchihewa, HKG
Modern manufacturing faces two main challenges: more quality at lower prices and the need for the productivity improvement. In ship building industry, companies need to respond to market requirements efficiently, keeping their products competitive while reducing the cost. When considering complicated ship production processes up to final hull block erection, the productivity of each work station for hull assembly mainly depends on the dimensional quality of hull blocks. Poor dimensional accuracy leads to reworks such as re cutting, mechanical or thermal correction against misalignment, excessive welding for wide gap and thermal straightening and this will subsequently increases the total production cost. One of the major dimensional accuracy control activities is the shrinkage margin design, which means that the optimal excess of plate is calculated and assigned into ship production drawings in order to compensate for the accumulated welding shrinkage through block assembly phases. In Sri Lankan context the most common practise to compensate for shrinkage has been to add excess material, usually 50-100 mm on one or two sides of a block that would be trimmed at the erection stage. Normally, this added material would be adequate to compensate for any weld shrinkage incurred during block assembly. It is however, a commitment to rework. This has been adopted due to the lack of accurate and reliable weld shrinkage and distortion allowance data. Even though there are some research findings on shrinkage factors it can’t be directly apply for the Sri Lankan industry as shrinkage factors may vary from shipyard to shipyard due to facilities, welding equipment, joint design, welding sequence, ambient temperature, and type of material. This research project provides a comprehensive weld shrinkage factor identification that enables neat construction capabilities for the shipbuilding industry in Sri Lanka. A key component of the research is a predictive weld shrinkage factor based on current ship designs, materials, and construction practices. Through this study, the shrinkage factors will be identified by a statistical analysis of data. It will be done from the development of check sheets, establishing of checking procedures, data gathering, and finally the statistical analysis of data. Since variety of variables can affect the determination of a shrinkage factor, it has to be decided the most crucial factors for particular production process and consider only those factors as the variables. Even though there are three major processes (panel fabrication, block construction, block assembly) in ship building the data was analysed only for data collected from panel fabrication and sample testing. Finally two equations were derived for sample testing and panel fabrication separately by providing dedicated factor for each and every considered variable. The obtained results were validated again by means of another sample testing and the deviation is less than 0.2 mm. The other processes were not considered due to complexity of the structures and data collection difficulty with in limited time frame. The block construction and assembly processes can be considered for the next step of this research and it can be done with the involvement of modelling software. From the modelling software the differences in each of complex blocks can be identified easily and measured values can be analysed against those differences. Then a comprehensive welding shrinkage compensation factor can be identified and it can be entered to the modelling software at the time of modelling the vessel.
item: Thesis-Abstract
CAD/CAM applications : a developmental strategy for the potential footwear industry in Sri Lanka
(7/22/2011) Mutunayake, APK; Kahangamage, UP; Punchihewa, HKG
The Sri Lankan Small and Medium scale Enterprise (SME) footwear industry is at crossroads. In order for the SME sector to survive and thrive in this competitive market, advanced technology needs to be introduced among other incentives. Developmental strategies for this industry are vital given the economic condition of these organisations and the global context of the footwear industry. The overall objective of this research is to identify the present state of technology usage in the SME footwear industry and to recommend pragmatic solutions to develop it. Data was collected from the random sample (nx=14) from the target population (Sx;:::40). Semi-structured interviews were conducted with the participants during the "Footwear and leather fair in 2007", which was jointly organized by the lOB and the Sri Lanka Footwear Association held at Bandaranaike Memorial International Conference Hall (BMICH) on 24th and 25th of November 2007. Further, unstructured interviews were conducted to collect data from the sample of experts (ny=4) selected from industry to obtain the experts' view about the industry to set benchmarks for the Common Resource Centre (CRC) and to validate the information collected from semi-structured interviews. Comprehensive analysis of the data elicited through the semi-structured and unstructured interviews was carried out. The main outcome of this study is a proposal with recommendations based on stakeholder and expert views for a CRC, which is to provide services to the footwear industry. Since the large-scale manufacturers may be able to maintain their own Computer Aided Design and Computer Aided Manufacturing (CAD/CAM) facilities, the proposed centre is to provide services especially to the potential SMEs. This CRC mainly will consist of CAD/CAM division, testing and laboratory services division, education, training and skills development division, research development (R&D) division, and administration and customer care division to provide services to the industry. The facts gathered suggest the immediate need of the establishment of CRC to uplift the potential SME footwear industry.
item: Conference-Full-text
A conceptual framework for the identification of barriers in automotive remanufacturing industry in sri lanka
(IEEE, 2021-07) Kahingala, NM; Gamage, JR; Punchihewa, HKG; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
Automotive remanufacturing provides a sustainable solution for waste generation in the automotive industry. Although the automotive remanufacturing industry is prominently seen in countries such as the UK, USA and China, it is now expanding to other parts of the world including India, Japan, Malaysia, and Singapore. Being a country having an automotive industry with significant value addition, Sri Lanka also possesses a high potential for remanufacturing. However, evidence of such industries is hardly seen. Therefore, the aim of the presented research was to develop a conceptual framework to identify barriers and propose solutions in the automotive remanufacturing industry in Sri Lanka. In this pursuit, a comprehensive review of the literature was performed. This was followed by informal interviews with people involved in the automotive remanufacturing businesses. The conceptual framework was then developed based on the challenges in each stage of the remanufacturing process against the three levels of interventions: Educational, regulatory body, and prevailing market conditions. It was revealed from the framework that most of the challenges were linked to the prevailing market conditions. Therefore, this paper provides a basis for encouraging the stakeholders to find suitable strategies in addressing the barriers associated with automotive remanufacturing in Sri Lanka.
item: Conference-Extended-Abstract
Design and construction of a machine to desalinate sea sand and to prepare it as fine aggregate for the construction industry
(2006) Allis, RLKG; Kahandagamage, GA; Lokuwithana, NPH; Punchihewa, HKG
Design and construction of a machine to desalinate and sieve sea sand is discussed. Initially, a full scale machine was designed according to the requirement. Then, the device was modelled using Pro/Engineer to depict the features and the operation of the desalination device. Finally, a miniature physical model of the proposed design was constructed to demonstrate the desalination and the sieving process.
item: Thesis-Full-text
Design and development of a fixture for Kelly bar mounting
Perera, PFS; Jayaweera, ND; Punchihewa, HKG
The Kelly bar is a bulky, long and heavy device that is used in piling. The Kelly bar surface is not smooth and contains ribs and grooves. The Drilling process makes many damages to the Kelly bar. These damages are required to be repaired in a workshop. Therefore,the gap of this research was the difficulty and the high cost associated with Kelly bar maintenance.The aim was to design a suitable fixture.The Objectives were to study the process and then create a new fixture and implement it in the workshop. In the methodology, the development process of the fixture and testing was explained. The research focused on the design and the development of the Kelly bar mount The. Kelly bar mount was required to do sliding and rotation both. This mount was required to be designed so as to prevent injuries to workers and damage to the environment, with low energy consumption.A Literature review was done.Thus,the main areas of the report were to identify a suitable fixture, to design and produce the mount and then test the mount. Next, a Project plan was developed and a project path was identified. Then a free hand sketch was identified. Then the optimal solution by design tree was shown and the conceptual design was obtaitend. Next, calculations for engineering strength were carried out. The material requirement plans and machine requirement plans were prepared. Afterwards,the model was designed,and carried out. So, the actual model was made. Based on this,the cost of production was analyzed . The investment and the cost saving points were discussed. After which the production was carried out. Next , testing was done.Then it was implemented in the workshop. Finally it was painted. For this research, the cost of production and opportunity cost were calculated. Based on this, a simple payback period as 29 days was calculated. Based on these results, finally,it was concluded that, implementing this fixture reduced the cost of operation massively in the workshop.
item: Thesis-Full-text
Development of a decision support tool to determine the state of train wagons in Sri Lanka railways
Keerthirathne, CU; Punchihewa, HKG
Different countries use different models to condemn railway wagons once they reach the end of their service life. However, in Sri Lanka, such transparent method is not being used. The method currently practiced mainly depends on the experience of the assessors. The Sri Lanka Railway (SLR) has 53 types wagons in its rolling stock and wrong decisions to condemn wagons can lead to considerable loss to the SLR and country’s economy in general. Therefore, this study focused on developing a decision supporting mechanism to condemn the train wagons in SLR by assessing their status using a well-defined and transparent mechanism. The objectives were to study the existing procedures for valuation and condemning process of BCGS in SLR, to develop a decision support mechanism to condemn BCGS and analyse the scrap value in a transparent manner, and to evaluate the mechanism. Data were collected using documents, and surveys, interviews and focus group discussions with relevant 18 employees in the SLR. Then, the decision support mechanism was developed based on Microsoft excel. Finally, it was evaluated by letting 3 evaluators to assess the status of two wagons of different conditions using the existing and the proposed mechanisms. The proposed decision support mechanism showed consistency compared to the current method. Extension of the developed method to encompass other types of units in the rolling stock is proposed as future work.
item: Article-Abstract
Development of a layout model suitable for the food processing industry
Wanniarachchi, WNC; Gopura, RARC; Punchihewa, HKG
The food processing industry is a subset of the manufacturing sector with unique challenges. Among these, ensuring food hygiene and preventing contamination are two issues of prime importance. Hence, designers have to overcome such challenges when designing facilities suitable for food processing.The paper formulates a model that simplifies the layout planning process for the food processing facilities (FPF) in order to help the designers. A generalised framework that helps to visualise the Facilities Layout Problem (FLP) was initially developed. A layoutmodel for FPF was then developed considering the unique features that need to be present in the layout.The model classifies the areas of FPF into five: primary, secondary, utilities, warehouse, and administration based on the activities and the level of risk present in food processing. It further proposes specific locations for the five sections in the factory layout. In order to test the performance of the framework and the model, a case study was conducted in a malted milk powder processing facility in Sri Lanka by changing its layout according to the proposed model. The framework and the model showed promise in its implementation. However, the approach and the layout model need to be evaluated in further cases in order to ascertain their usability and performance. 1.
item: Thesis-Full-text
Development of a queuing simulation model for train passengers
Wimalarathne, KKS; Punchihewa, HKG
Sri Lanka Railway (SLR) is currently having a schedule with uneven time intervals between trains. It reduces the popularity of the railway system and as a result new passengers hesitate to join the system. Hence, this current system is generally used by regular travellers only. In order to seek ways to improve the train schedules simulation based approaches have not been used in Sri Lanka. Therefore, the aim of the research was to develop a simulation model to minimise queuing time of passengers while maintaining an even interval between trains. A passenger survey and a railway survey were carried out to find current issues related to the timetable and the service. Considering the feedback of passengers, a simulation model was created using the Anylogic simulation software for the current train scheduling and the proposed train scheduling systems. The simulation model shows that passenger queuing time is able to be changed using the parameters of the model. Results also indicate that queuing can be potentially reduced using even time intervals between trains. However there could be a necessity to change the number of compartments to cater for the number of commuters in the proposed system. In addition the proposed system needs to be piloted in order to understand and overcome the practical limitations. This could potentially help to improve the popularity of the railway system in Sri Lanka. The operation model was developed between two stations due to limitation of the software. Thus, it is proposed to develop the model to cover the entire train fleet and the network to obtain more accurate and repetitive results.
item: Thesis-Full-text
Development of a solid feed block forming machine for cattle
Silva, SAPS; Punchihewa, HKG
Livestock statistics show that there are 1.2 million milking cows and 0.4 million buffaloes in Sri Lanka and the Department of Census and Statistics shows an annual per capita consumption of milk and milk products of about 4.6 kg/year. However, these values are comparatively low compared to the developed countries. Therefore, achievement of the selfsufficiency levels in dairy industry of Sri Lanka needs significantly both in growth and productivity. The issues which are slowing down or hampering the growth and productivity can be categorized on milk production related, distribution and marketing related, extension and support service related, consumer concern related, policy related and feeding related. Although, the nutrition is a key factor for the performance, health and welfare of dairy cattle, the prevailing cattle feeding has become an issue today for growth and production became of mostly primitive nature of practice, which is a challenge for the increased commercialization of dairy industry. Consequently, it has been identified that the well-recognized method of feeding cattle in commercial dairy industry is solid nutritious feeding blocks which are made of hygienically prepared agricultural residues. Aim of this research were producing suitable feed block and developing block making machine for the cattle in Sri Lanka. The objectives of this research were to identifying the requirements for cattle feed blocks and their manufacturing, to examine suitable shapes and sizes for feed blocks, and to design and manufacture a feed block machine and to test the machine for verifying the results. Suitable block forming methods, technologies and the suitable machineries were recognized through literature survey, brainstorming sessions and experimental procedures. Accordingly, design and fabrication of a novel block making machine was successfully completed. Suitable size and weight of the block, recommended recipes, production capacity of the machine, block forming method and type of power source were identified. Finally a machine was fabricated to suit the parameters identified above and was tested. Results revealed that the fabricated machine can address the design requirements of the machine. The production capacity of the machine was 100 blocks/ h with 200 mm × 200 mm ×110 mm size and 2 kg weight. The solid cattle feed blocks can be used to fulfill the nutritional requirements of dairy cattle under safe conditions with affordable cost. Further, adoption of this technology supports to make an easy feeding mechanism and enhance milk production through available agricultural residues and available technology in Sri Lanka. Adding automatic raw material preparation system and the automatic feeding system to the compaction machine are proposed as further improvements.
item: Thesis-Full-text
Development of an anthropometric database to determine school furniture dimensions for grade six students
Meedeniya, KL; Punchihewa, HKG
Anthropometry of school children is essential for decide the dimensions of furniture. However, no students‟ anthropometric studies have been carried out in Sri Lanka after 1979. Thus Sri Lanka depends on anthropometric measurements of other populations when designing furniture and other components. The deviations from the expected data and the available data of anthropometry may lead to errors in making decisions for selecting suitable furniture, equipment, and other components and importing them as well. Use of such incorrect items may result in long term health effects. Therefore Sri Lanka needs to establish anthropometric data for school children. The aim of this dissertation was thus to study anthropometric measurements required to determine the dimensions of school furniture for grade six based on a study in the Sabaragamuwa province of Sri Lanka. The research was carried out using 508 students. The results obtained from the data analysis were used to compare existing furniture dimensions available in the selected schools and standard furniture sizes specified in Indian standard IS 4837:1990 for school furniture dimensioning. A set of recommended desk and chair sizes of grade six students based on the anthropometric data taken from the students in Sabaragamuwa province have been proposed at the end of the report. However, a comprehensive island wide anthropometric survey is recommended covering all districts, including student categories from grade 1 to grade 12 and revisit the existing furniture dimensions because no detailed study has been performed after 1979 in Sri Lanka and also students‟ anthropometry may have changed with the change of standard of living, food habits, intra-individual, inter-individual, and secular variation of measurements during the past 40 years.
item: Thesis-Full-text
Development of manual lifting guidelines for sri lankan population
Dhanushka, HMB; Punchihewa, HKG
Restricted work time due to poor occupational health and safety practices take a particularly heavy toll in developing countries, such as Sri Lanka. Work-related musculoskeletal disorders are among the most frequently reported causes of lost or restricted work time. Low back disorder is the major musculoskeletal disorder in most of the industries, where lifting is associated as a major risk factor. Therefore it is important to design manual lifting tasks to not to exceeding the limits of musculoskeletal systems to avoid musculoskeletal disorders. Ergonomists have conducted research on manual material lifting over last few decades to reduce the low back disorders. As a result of above research there are large number assessment lifting tools developed. There is no evidence on validating the above mentioned lifting assessment tools to the Sri Lankan context and also there is no ergonomic guideline or lifting assessment tool developed considering the body sizes of Sri Lankan population. This study would lead to the development of ergonomic guidelines for manual lifting for Sri Lankan population using existing lifting assessment tools. Revised National Institute for Occupational Safety and Health (NIOSH) Lifting Equation, American Conference of Governmental Industrial Hygienists lifting Threshold Limit Values and Washington Industrial Safety and Health Act Rule Lifting Calculator were identified as key lifting assessment tools. A case study was conducted in a manufacturing plant to check the validity of the above manual lifting assessment tools identified through the literature review. Ergonomic discomfort scale was used as a tool for getting the workers response on above tools. The outputs of all the lifting assessment tools calculated and converted to lifting indexes similar to the lifting index calculated in NIOSH lifting equation. Results of the lifting assessment tools compared with the ergonomic discomfort feedback of the workers who performing lifting tasks. The ergonomic guideline for Sri Lankan population was developed by using the results of above comparison. The developed guideline was validated using a case study. The developed guideline was validated only for male population and future development of manual lifting guideline for Sri Lankan female population is possible.
item: Conference-Abstract
Development of temperature prediction model for rubber caster wheels using finite elements
(2017) Wijayasundara, AV; Ranaweera, RKPS; Punchihewa, HKG
Caster wheels made with rubber rings fail during dynamic loading as a result of heat buildup. Temperature inside caster wheel increase gradually due to hysteresis effect of rubber material. Therefore, dynamically testing of rubber caster wheels is critical to evaluate new designs for their successful application. In such tests, caster wheels are rotated on a drum under a predetermined load and speed to evaluate their performance. Alternatively, this paper proposes a temperature prediction model to forecast the failure of the wheel using numerical approach. The objectives were to evaluate the temperature development inside the wheel using finite elements. In this pursuit, temperature inside several caster wheels were measured during dynamic tests. Based on the logged temperature data and raw material tests, finite element simulation of caster wheels was performed. Simulations were carried out in three steps; at first structural simulation, followed by determination of energy conversion factors and finally thermal simulation. The predicted temperature profiles and test data were closely matching with a R2 of 0.9, which eliminates the requirement for iterative dynamic tests. However, further work is needed to predict the failures of caster wheels based on developed model.
item: Thesis-Full-text
Devolopment of a mechanical dryer for drying coco peat to use growing media
Adikari, AJL; Punchihewa, HKG; Manthilaka, MMID
Coir peat which is a by-product of extracting fibre from coconut husk is considered an excellent growing media in horticulture industry. The basic features of coco peat is having good water holding capacity, ability to control PH and EC (electric conductivity) and good air porosity. Demand for the coco peat is increased continuously due to the above reasons. In addition, use of sphagnum peat moss and rock wool is replaced by coco peat very easily due to scarcity and environment issues ofthose growing media. In the present Sri Lankan context, sun drying is widely using to dry the wet coco peat up to the required moisture level before it is compressed. Since coco peat is having a low density (0.1 kg/L), it is needed to be compress before transportation. However sun drying is totally depending on the weather pattern and it is not advisable to depend on sun shine due to the present demand and reliability' on the industry. Therefore possibility to look at thermal drying is important while retaining the relevant properties of coco peat. Studies were carried out to evaluate the performance of combining both rotary drum dryer and flash dryer which are used in similar industries. Four key factors were taken into the study are moisture level, temperature, feed rate and residence time. A set of combinations of the above factors were tested and studied. More than two hundred samples were taken under different settings and corresponding output moisture percentages were measured. Compressed coco pellets were made out of dried samples and then expansion height of each sample was also measured for verification ofthe expansion quality of dry material. The low moisture levels of feeding material affected the temperature of the system and feed rate. The frequency didn’t play a major role. However feed material with high moisture, temperature and rotating frequency positively affected the output moisture while feeding rate was negatively affected. According to the research and considered input variable, this system shows coco peat can be dried when input material moisture is around 60% and temperature 90 -100° C and feed rate around 15 1/min and output material will be comply the requirement to use as growing media. Coco peat with low moisture contents should be exposed to heat at low temperature with higher feed rates, but, material with high moisture content should be exposed to high temperatures and low feed rates as seen with this research. However, it is advisable to take more measurements with very close steps to fine tune the model parameters before implemented on the field.
item: Thesis-Full-text
Effect of air and chilled emulsion minimum quality lubrication (ACEMQL) in machining hard to cut metals
Senevirathne, SWMAI; Punchihewa, HKG
Effect of Air and Chilled Emulsion Minimum Quantity Lubrication in Machining Hard to Cut Metals A novel approach of cutting fluid application was developed and its performance in machining hard to cut metalswas investigated. The study focused on turning AISI P20 and D2 tool steels using coated carbide cutting tools. For this study, an improved minimum quantity lubrication (MQL) method named, air and chilled emulsion minimum quantity lubrication (ACEMQL) method was developed to evaluate its effect on tool life and surface finish of material being machined. Trials were carried outfor ACEMQL with cutting fluid temperatures from 5°C to 20 °C in steps of 5 °C.In order to obtain a benchmark for comparison ofresults, set oftrials were carried out for dry cutting and flood cooling at 25 °C while all other parameters kept same as in ACEMQL method. Trials for ACEMQL method resulted in better tool life and surface finish for both AISI P20 and AISI D2 tool steels when compared with dry cutting and regular flood cooling methods. Minimum tool wear in machining AISI P20, was observed at 15 °C with ACEMQL, and it has shown a trend of increasing tool wear when temperature was lowered to 10 °C and 5 °C. A tool wear reduction of 97% from dry cutting, and 93% of flood cooling, is observed with ACEMQL at 15 °C. At 10 °C also ACEMQL has shown a reduction in tool wear by 94% compared with dry cutting and 86% compared with flood cooling. However, at 20 °C, it is observed that there is an increase in tool wear compared to flood cooling by 29%. Similarly, in machining AISI D2, minimum tool wear was observed at 15 °C with ACEMQL, and it has shown a trend of increasing tool wear when temperature was further lowered to 10 °C and 5 °C. A tool wear reduction of 96% from dry cutting, and 93% offlood cooling, is observed with ACEMQL at 15 °C. At 10 °C also ACEMQL has shown a reduction in tool wear by 71% compared with diy cutting and 57% compared with flood cooling. Although use of ACEMQL shows an improvement in surface finish in machining both AISI P20 and D2, it has not shown significant difference with reduction oftemperature in the investigated steps oftemperatures. For AISI P20, the least surface roughness obtained is 0.97 pm Ra and it is at 5 °C. It is a 35% reduction with respect to dry cutting condition and 31% reduction in comparison with flood cooling condition. For AISI D2, the minimum surface roughness obtained is 0.82 pm Ra and it is at 5 °C. It is a 49% reduction with respect to dry cutting condition and 40% reduction in comparison with flood cooling condition.Research on the effect of cutting velocity, feed rate and depth of cut, on tool life and surface finish with ACEMQL is suggested as future work. Further, economic feasibility analysis is suggested to find out the suitability of ACEMQL in local die and mould manufacturing industry, and also research on relationship between chip colour and cutting condition, and reasons for the colourisation is suggested as future work.
item: Conference-Full-text
Effect of envelope energy performance enhancement strategies on building energy loads: case study for a tropical institutional building
(IEEE, 2022-07) Ariyaratne, RGRNK; Karunathilake, HP; Punchihewa, HKG; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Building energy simulation tools are used during the design process of a building to improve its energy performance. In this study, envelope thermal performance enhancement strategies were evaluated using eQUEST building energy simulation software considering the energy saving achieved related to cooling and ventilation energy consumption, for a tropical institutional building, in order to compare their performance. Fixed and building shading strategies have resulted for about 3.9% energy saving and other envelope thermal performance enhancement strategies have resulted up to 4.7% energy saving. Further energy consumption variation with envelope and roof thermal transfer values (ETTV, RTTV) were also evaluated. The results have shown that ETTV has statistically significant correlation with averaged building cooling and ventilation energy consumption. The findings allow building designers to identify the best upgrade options for achieving code compliance in Sri Lankan institutional buildings.
item: Conference-Full-text
Effect of minimum quantity lubrication aerosol temperature on tool life in machining aisi p20 and d2 steels using coated tungsten carbide tool inserts
(IEEE, 2016-04) Senevirathne, SWMAI; Punchihewa, HKG; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
This study focused on turning AISI P20 and D2 tool steels using coated-carbide cutting tools. In this experimental investigation, an emulsion cutting fluid (CF) aerosol temperature with minimum quantity lubrication (MQL) was varied from 5 oC to 20 oC and its effect on the tool life was evaluated. Trials were done for dry cutting and flood cooling at 25 oC also in same conditions. MQL revealed better tool life for both steels than dry cutting and flood cooling. The tool wear for P20 showed a quadratic behaviour against aerosol temperature, with minimum occurred at 15 oC. At 15 oC, 97% and 93% tool wear reductions were observed from dry cutting and flood cooling respectively. However at 20 oC, tool wear increased by 29% from flood cooling. For D2 steel, similar characteristics were observed with minimum wear at 15 oC. A wear reduction of 96% from dry cutting, and 93% from flood cooling was observed with at 15 oC. MQL at 15 oC leads to a potential means of reducing machining costs. However, trials need to be repeated with different tool material, work-piece material and aerosols to ascertain the generalizability of the findings.
item: Conference-Full-text
Efficiency improvement of solar photovoltaic thermal systems by experimental and numerical analysis
(IEEE, 2020-07) Karunasena, UTRK; Karunarathna, MAP; Kumara, DGAS; Manthilake, MMID; Punchihewa, HKG; Edussooriya, C; Weeraddana, CUS; Abeysooriya, RP
The power output of solar panels shows an invene relation with increasing its operating temperature and that affects largely for countries tike Sri Lanka, wbich are situated near the equator. Possible cooling techniques, which are aligned with the Sri Lankan context, were studied by referring to past research and available systems. Rear side forced water-cooling with a thermal coUector wbich is known as the hybrid system was identified as the most feasible technique by considering economic and environmental facton. The theoretical model was developed to estimate the design parameters of the thermal collector and cooling performance. The number of ten thermal collector design configurations were modeled and analyzed the cooting performance using ANSYS fluent simulations. The best design configuration was identified based on heat transfer and manofacturiog capability. A prototype of the selected design was manufactured to investigate the cooling performance experimentally. The experimental setup was developed using two 100 Watts solar panels and a smaU scale cooUng tower.Both power and panel temperature variation were analyzed both numerically and experimentally. The numerical model was vatidated using experimental results and design parameters were optimized as it gives a better cooling performance. Both numerical and experimental analysis shows that integrating a rear side cooling system would increase both electrical and thermal efficiency by 65%. The electrical efficiency improvement is 2.5 % and electrical power generation is increased by 28% compared to the panel without cooling. Considering the cost benefits and the environmental conditions of Sri Lanka, using a solar PV hybrid system is a feasible option to enhance both electrical and thermal gains.
item: Thesis-Full-text
Fea-based method to predict dynamic test failures of industrial rubber castor wheels
Wijayasundara, AV; Punchihewa, HKG; Ranaweera, RKPS
Castor wheels are used in various applications including industries, hospitals, offices, shopping trollies, air ports and other material handling applications. These applications demand different properties from castor wheels, such as dynamic load capacity, high speed capability, and capability to operate in hot and cold environments. Design of a castor wheel plays a major role to fulfill those various demands while being competitive in the market. Dynamic test of castor wheel is one of the main tests done on new castor wheel designs to evaluate its performance for an application. Due to manual trial and error practice used to test new designs in dynamic test, wheel development cost and lead time for deliver new castor wheel designs for new customer requirements is high. In order to evaluate wheel designs in early stages of development in dynamic test performance, Finite element model was developed to check castor wheel dynamic performance using combination of finite element analysis (FEA) techniques and raw material testing. Initially six samples of castor wheels were selected and dynamic test was carried out on them at various loads to evaluate temperature development inside the wheel and failure modes. Two sets of raw material testing, namely uniaxial tensile test and dynamic mechanical analyze test (DMA), were done on rubber and plastic materials which are used to make castor wheels. One wheel was selected as a case study to develop FEA model. As first step, 3D static loading simulation was done for the selected wheel. Total energy rate was defined for wheel in dynamic motion by data from static test using equations. 2D axisymmetric FEA model was developed as next step to evaluate temperature development of the castor wheel. Calculated energy rate was distributed among rubber elements as heat sources combining with DMA results to predict temperature inside the 2D profile using transient heat. Wheel failure analysis was carried out by combining predicted temperature profile and static loading case with temperature dependent properties of materials used. It was defined as a good design if castor wheel shows higher safety factor in failure simulation. From the case study, step-by-step method was developed to simulated castor wheel designs and evaluated failure. Four castor wheels were simulated according to developed model and predicted temperatures were compared with actual dynamic test temperature to validate the proposed model which showed good match with practical data. As future work, advanced failure analysis of caster wheels can be proposed, which should be carried out considering material chemistry and behavioral changes of materials with heat and fatigue loads.