MESII - 2022

Permanent URI for this collectionhttp://192.248.9.226/handle/123/19529

Browse

Now showing 1 - 20 of 22

item: Conference-Abstract
Materials Engineering Symposium on Innovations for Industry 2022 - Pre Text
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Abeygunawardana, AAGA
item: Conference-Abstract
A monitoring method for the degree of curing in epoxy adhesives using direct current resistivity
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Janith, GI; Herath, WHS; Weragoda, VSC; Abeygunawardana, AAGA
Adhesive bonding is a widely used technique in material joining. Research focused on enhancing the properties of resin-based adhesive systems is critically important in manufacturing quality control. One specifically important aspect is the monitoring of cure progression of the adhesive. Commonly practiced cure monitoring methods such as Differential Scanning Calorimetry (DSC), Dielectric Analysis (DEA) and Dynamic Mechanical Analysis (DMA) are ideal for laboratory evaluations but not conducive for in-situ cure monitoring. In-situ cure monitoring techniques are vital as they provide better control over processing parameters. This study introduces a Direct Current Resistivity (DCR) based cure monitoring method. It is simple, cost-effective, reliable, and more importantly, industry friendly. The fast response of direct current measurements combined with the simplicity of the analysis makes this method suitable for real-time cure monitoring.
item: Conference-Abstract
Numerical simulation of lead-free bismuth perovskite by using scaps (solar cell capacitance simulator)
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Akmal, UKDM; Fernando, WMTV; Galhenage, AS; Abeygunawardana, AAGA
A perovskite solar cells were studied using the Solar cell capacitance simulator (SCAPS). The effect of the cation on the performance of perovskite solar cells with MA3Bi2I9 as the light-absorbing material and perovskite solar cells with Cs3Bi2I9 as the light-absorbing material were simulated and compared. MA3Bi2I9 and Cs3Bi2I9 achieved efficiencies of about 8.6% and 13.6%, respectively. The fluctuation in light absorption caused by the cations significantly affects the performance of perovskite solar cells. This research also investigated the effects of band-to-band recombination, absorber layer defect density, perovskite-electron transport layer interface defect density, perovskite-hole transportation layer defect density, series resistance, shunt resistance, and operating temperature on the solar cell performances.
item: Conference-Abstract
Mathematical modelling of mechanical behavior in randomly oriented micro crystalline cellulose-based polymer composite
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Arthanayake, SAMASB; Pallewela, RSJ; Amarasinghe, DAS; Samarasekara, AMPB; Abeygunawardana, AAGA
There are many theoretical models to predict the mechanical properties of Continuous long-fiber composites. But there is no proper mathematical model for randomly oriented short fiber composites (ROFC). This research aims to develop a useful mathematical model from fundamentals for a randomly oriented short fiber reinforced composite. The developed theoretical model was validated using a computational Analysis.
item: Conference-Abstract
Mechanical characterization of biological soft tissues under tensile loading - experimentation and numerical aspect
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Edirisinghe, AD; Weerasuriya, MACS; Abeygunawardane, AAGA; Abeygunawardana, AAGA
For the first time in Sri Lanka, rectus femoris muscle has been used to characterize the mechanical properties of human soft tissues. These properties can be used to synthesis artificial tissue for bio engineering applications; if these biological soft tissues are to be replaced with polymer based biomaterial. Initially, uniaxial tensile test was performed on cadaveric samples obtained from national hospitals with the relevant ethical clearances. The obtained stress vs. strain graphs elucidates hyperelastic behaviour within non damage domain with initial J shape portion. It was also noticed that mechanical properties are highly non homogeneous as stress vs strain curves are different at different locations on the same cadaver. Variation of the “Damage” variable was also calculated to understand the degradation tendency of these biological materials under uniaxial tensile loading. ‘Snudden’ formula was used to obtain shear modulus of these cadaver samples through curve fitting technique. A numerical model was developed using commercially available FEA software ‘ABAQUS’; Based on the best fit analysis for the obtained stress vs stretch ratio graphs; ‘Polynomial Strain Energy Density Function with N=2” was used to simulate the muscle samples. This numerical model also includes damage parameter through the introduction of “Ductile Damage” of FEA and the parameters of the numerical model were all calibrated well with the experimental observation.
item: Conference-Abstract
Development of cellulose-based precursor solution for electrospinning technique
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Basnayaka, BMCGK; Udeshini, AA; Samarasekara, AMPB; Amarasinghe, DAS; Abeygunawardana, AAGA
To electro-spin a polymer solution, certain specific conditions need to be met, for example, acetyl content (A) (38- 40%), degree of substitution (DS) (2.3-2.5), molecular weight(M) (30,000 100,000 gmol-1) solution system of CA 15w%, acetone 80w% and water 5w%. This study aimed to produce an electro-spinnable cellulose acetate precursor solution from raw cotton. This paper discusses the cellulose extraction process as well as the characterization process. The electro-spun cellulose acetate fibers are significantly crucial to high-tech product designs.
item: Conference-Abstract
Design and optimization of linear actuator for biomedical applications
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Chandrasiri, WAD; Rashmika, WAD; Adikary, SU; Abeygunawardana, AAGA
Microelectromechanical system (MEMS) actuators are a promising innovation that is essential to the development of a wide variety of biomedical devices. The invention of smaller fluid pumps has been valued with increasing interest, these miniaturized micro pumps are designed to handle a very small, precise, and controllable amount of fluid normally in the range of μl/min to ml/min. Thyroid hormone imbalance is a highly increasing, common, genetically or non-genetically disease, which is conducted to Hypothyroidism (an underactive thyroid gland) and Myxedema Coma. So, levothyroxine should be injected frequently into the human body to maintain the metabolic system. This research was carried out to design a linear actuator for a micro pump that injects a certain dose of levothyroxine hormone into the human body accurately. Lead Zirconate Titanate (PZT) gives a high piezoelectric charge coefficient value with high frequency and stiffness that is required for the micro pump. Theoretical mathematical calculations of the piezoelectric stack configuration were carried out to get the displacement of the actuator and maximum displacement. Considering water as the fluid, an equation for flow rate was derived theoretically with supposing fluid behave as a laminar flow. Finite Element Analysis (FEA) was performed to identify the suitable dimensions of the micro pump which is compatible with the flow rate of the fluid.
item: Conference-Abstract
Characterization of creep behaviour of viscoelastic materials by ultrasound pulse- echo technique
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) HEWESSAGE, HDDN; KOTHALAWALA, SSW; Sivahar, V; Abeygunawardana, AAGA
For any viscoelastic material, creep is a phenomenon which tends to change microstructure and the mechanical properties of material. Therefore, it is important to quantify and predict the creep and creep rate of a component. In this investigation, several samples of LDPE were used to measure the creep and both ultrasonic attenuation and velocity measurements using a 5 MHz transducer were employed for characterizing the samples. Our findings indicate that velocity and attenuation measurements can be used to characterize and quantify creep and creep rate of viscoelastic materials.
item: Conference-Abstract
Development of cellulose fiber reinforced soil-based composite wall panels using selected lignocellulosis materials
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Jayaweera, WMIS; Malshan, MMH; De Silva, GIP; Fernando, TN; Abeygunawardana, AAGA
The present study focuses on preparation of composite wall panels, reinforcing with three different pre-treated lignocellulosic material fibers - bagasse (B), paddy straw (PS), and banana stem (BS). Soil-based composite wall panels were prepared by mixing cement, laterite soil, and lignocellulosic materials in the weight ratios of 1: 1: 0.025. Morphological characteristics, water absorption, flexural strength, and thermal conductivity were tested in prepared wall panels after keeping at curing period of 28 days. The characterization results of molded wall panels indicate the variation of flexural strength as 1.85 - 4.05 MPa, percentage of water absorption as 14.7-20.2% and thermal conductivity as 0.131 -0.252 W/mk. The characteristics of some molded wall panels prepared in the present study were at a satisfactory level compared to the market available wall panels.
item: Conference-Abstract
Development of cement, waste paper, and natural fiber based composite for ceiling sheet
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Kumarasinghe, PDRS; Sachintha, KKN; Udayakumara, SV; Abeygunawardana, AAGA
This study was focused on developing material for ceiling sheets using waste paper and cement. Every day, a large amount of paper waste is discarded into the environment. The new ceiling composite is produced, which is low-cost, lightweight, and non-hazardous while contributing to waste management. Coir fiber is used as reinforcement in the composite. Samples were prepared by adding 0.5%, 1%, 1.5%, and 2% of coir fibers to the total weight of the samples. The ratio between waste paper pulp and cement was kept at 1:1. Flexural strength, water absorption, thermal conductivity, and density of the samples were measured after 28 days of hardening. The optimum fiber percentage was identified by analyzing the results. After identifying the optimum fiber percentage, the percentage variation of flexural strength was studied with the fiber length. Variation was studied for the 1, 1.5, 2, 2.25, 3, and 3.5-inch fiber lengths. A cost analysis and comparison of the properties with the commercially available ceiling sheets were done.
item: Conference-Abstract
Preapartion and characterization of porous graphene from Sri Lankan vein graphite
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Manikanth, P; Rasandran, S; Sitinamaluwa, HS; Abeygunawardana, AAGA
GO (Graphene Oxide) is one of the most promising candidates for application of energy storage devices such as batteries and supercapacitors. For energy storage applications, surface area of the material is very important. In this study, graphene oxide was subjected to KOH activation process to enhance its surface area via creating nano and micro pores in the structure. The effect of the activation time on the porous structure and surface area was studied. KOH activation was carried out for 0.5h, 1h, 1.5h and 2h, and the resulted Activated Graphene Oxide (AGO) was characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. Also, the specific surface area of the resulting materials was compared using methylene blue adsorption method. The results indicate that the activation at a temperature of 800oC and a time of 2 hours gives the hierarchical pore structure with best surface area.
item: Conference-Abstract
Quantitative estimation of residual stresses in quenched steelthrough ultrasonic parameters
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Rangana, HGS; Ishara, WKG; Sivahar, V; Abeygunawardana, AAGA
After manufacturing and heat treatment processes, residual stresses are present in the specimen. Quenching is the heat treatment process that forms residual stress in metals. Two methods are used to find residual stresses in the industry, which are Destructive and Non-Destructive. This research is focused on estimating residual stresses in quenched steel using the Ultrasonic non-destructive method. Medium carbon steel is the material which is used in the research, and ultrasonic attenuation coefficients uses to correlate the variation of stresses with it. ABAQUS modelling software is used to simulate residual stresses.
item: Conference-Abstract
Development of soil based composite wall panel using locally available laterite soils
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Samarasinghe, MMA; Gunathunga, WPS; De Silva, GIP; Fernando, TN; Abeygunawardana, AAGA
This research focus on developing laterite soil-based composite wall panels by using soil cement mixture, reinforced with cellulose fibers from pretreated cornhusk. In this, effect of various laterite soils and cement proportions of the mixture on the properties of wall panels like flexural strength, water absorption and thermal conductivity were determined. It has been observed high Al2O3+Fe2O3 content, good particle size distribution, lower clay content of soil shows good performance of wall panel properties. Further, lowering the cement content of the mixture reduces the wall panel performance.
item: Conference-Abstract
Molecular dynamics simulation of electric double layer capacitance of graphene electrodes
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Sandaranga, KAM; Kumara, NAHWS; Sitinamaluwa, HS; Abeygunawardana, AAGA
Graphene has been identified as a promising material for electric double layer capacitors (EDLCs) owing to its large surface area and high conductivity. This study aims to develop a computation model to study the double layer formation of graphene electrodes when it is in contact with an electrolyte. Classical molecular dynamic simulation method was selected as a promising method to study the electrode-electrolyte interactions of electric double layer capacitors. This simulation study was performed to understand the electric double layer capacitance of graphene electrodes and acetonitrile electrolyte. The computational analysis has been performed using the molecular dynamics tool (LAMMPS). In this study, to understand the EDL performance on capacitance, number density profile, and charge density profile, data was obtained. The simulations show that electrolyte (acetonitrile) is formed into a highly ordered structure near the surface in graphene-based systems, which leads to electric double layer formation. According to capacitance values that have been calculated, the presence of defects in graphene reduces the electric double layer capacitance.
item: Conference-Abstract
Design/fabrication of bi-axial tensile testing machine and numerical modeling of polymer composite under bi-axial stress state
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Arachchi, KADDK; Sandanayaka, SMP; Abeygunawardane, AAGA; Weragoda, VSC; Abeygunawardana, AAGA
In real engineering applications, materials are subjected to different types of loads applied in several directions. Characterizing materials using the Uni-axial tensile testing can be only enough for Isotropic materials. But it is not accurate when testing the Anisotropic materials where the properties vary with different crystallographic orientations. The main scope of this research is to Design & Fabricate the Sri Lankan first ever Bi-Axial Tensile Testing Machine to Characterize Polymer Composites. This study enabled to fabricate a full-scale Bi-Axial Tensile Testing machine for the first time in Sri Lanka. The machine uses four linear actuators which allow cruciform specimen subjected to load from two independent directions. A non contact strain measurement technique using digital Image correlation has been used to measure the strain induced in the specimen. MCalibration – an optimization numerical tool was used to calibrate the best fit material model for the particular application under the biaxial stress state, and a commercial FEA software ABAQUS was used to build and analyze the tested material for its anisotropic nature.
item: Conference-Abstract
Simulation study on the effect of calcium carbonate and talc volume fractions on the mechanical properties of thermoplastics
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Thilakarathna, TDK; Erathnage, TU; Udayakumara, SV; Abeygunawardana, AAGA
Today, particle reinforced composites are widely used in the manufacturing of thermoplastic products for a variety of applications. Other than the trial-and-error method, numerical methods are used to obtain the properties of composites. However, in numerical methods, defining the geometry of the Representative Volume Element (RVE) and boundary conditions are challenging and time-consuming tasks. To get control of these issues, Ansys Material Designer can be introduced as a modern solution with the defined composite geometries of different types of composites. In this study, the mechanical properties of the CaCO3 and talc-filled composites of HDPE, LDPE, and PP are studied under different particle volume fractions by using Ansys Material Designer. Improved mechanical properties were given by the talc-filled thermoplastic composites.
item: Conference-Abstract
Synthesis of calcium oxide nanoparticles from waste eggshells for seed priming
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Jayaneththi, Y; Nipunika, U; Galhenage, AS; Abeygunawardana, AAGA
Environmental pollution and scarcity of natural sources are two major problems that society faces at the present. Eggshells are a waste that is discarded without any value which contributes to the environmental pollution. In this study, a method is introduced to add value to the eggshells and used it for seed priming. Seed priming is a technique that introduced as a solution for the decrease in plant growth and crop yield due to the environmental pollution. Calcium oxide nanoparticles were synthesized from waste eggshells through a combined process of ball milling and calcination. The eggshells and the calcined eggshell powder were characterized by Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), Fourier-Transform Infrared Spectroscopy (FTIR), and X-Ray Diffraction (XRD) CaO was synthesized at different temperatures and different time periods from eggshells. Green gram seeds were chosen for the study on seed priming as quick results can be obtained. The green gram seeds were treated with CaO suspension. The effect of CaO nanoparticles on seed priming and germination were also investigated.
item: Conference-Abstract
Modelling and simulation of piezoelectric nanogenerator using zinc oxide for wearable electronics
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Vithusan, T; Nashira, MNF; Adikary, SU; Abeygunawardana, AAGA
A vertically integrated Zinc Oxide nanowire (NW) based piezoelectric nanogenerator (NG) was modelled for energy harvesting applications. Nanogenerators were modelled on unit element based and arrays based and were simulated using COMSOL Multiphysics 5.3 and the mathematical equations were derived considering the coupled piezoelectric and mechanical behaviour. Moreover, the voltage output of the single NW under a constant lateral force was analysed varying with the NW dimensions in terms of aspect ratio. The results showed that the compression of ZnO NW gives more output voltage compared to the bending of the NW for the same NG. The stress variation was analysed for the range of nanowire dimensions (aspect ratio) using the software. The influence of aspect ratio, length, and diameter on the output electrical potential of the ZnO nano wire-based NG was investigated using simulated results. It was observed that when the diameter is increasing along with the aspect ratio decreasing for constant length, electrical potentials at the output decrease. The aspect ratio was analysed by maintaining a constant dimeter and with variable length. When the length is increasing along with the aspect ratio, the voltage output shows lesser deviation. The theoretical and simulation results also proved that the length of the NW does not influence the piezoelectric potential in a lateral bent NW. The unit element and then the integrated array design with PMMA filler and insulator were modelled by assembling such 9x9 (81) unit elements with the inter wire distance of 40nm and the results were analysed.
item: Conference-Abstract
Designing an elastomer for reinforced elastomeric cushion bridge expansion joints
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Welivita, WKCS; Wijayasiri, ISWC; Weragoda, VSC; Abeygunawardana, AAGA
This project is focused to improve the properties and to avoid the premature failures of the Reinforced Elastomeric Cushion Bridge Expansion Joint which is used by the industrial organization of Expressway Operation, Maintenance and Management Division of Road Development Authority in Sri Lanka. During the project, COMSOL Multiphysics software was used to analyze the stresses of the expansion joint. Rubber compounds were mixed in a two-roll mill according to a predetermined formulation and were vulcanized using a compression molding machine. Tensile strength, hardness, abrasion resistance, aging resistance (ozone aging and hot air oven aging) were measured according to the standards.
item: Conference-Abstract
Development of a theoretical model to predict filtration efficiency of electret based masks
(Department of Materials Science and Engineering, University of Moratuwa., 2022-11) Wimalasinghe, BP; Siriwardhana, BM; Attygalle, D; Abeygunawardana, AAGA
In this study, a 2-Dimensional computational model to predict the filtration efficiency of the electret layer of N95 facemask was developed. The fiber packing density, fiber diameter and fiber layer thickness were included as the parameters defining the fiber structure for the model. Random 2-Dimensional fiber structure were designed using MATLAB and AUTOCAD software while COMSOL Multiphysics was used to simulate filtration mechanisms. The developed model was used to study the filtration mechanisms behavior with various surface charge densities and fiber packing densities. Also, the effect of sticking probabilities with the electrostatic and mechanical filtration were observed.

Browse

Recent Submissions