Browsing by Author "Somaweera, D"

Now showing 1 - 3 of 3

item: Thesis-Abstract
Characterization and modeling of thermo-mechanical behavior of solid tires with graphite as a heat transfer enhancer
(2023) Somaweera, D; Abeygunawardane AAGA; Weragoda VSC; Ranathunga S
The solid resilient tire construction consists of three layers namely tread, cushion and base. The cushion or the middle layer provides a comfortable ride but also needs to reduce the heat buildup when the tire is subjected to heavy loads. Repeated loading on the cushion compound causes heat generation due to hysteresis and combined with the heat due to friction from tread needs to be relived promptly to reduce the risk of tire damage. The aim of the study is to enhance the thermal properties of the cushion compound of the solid tire using Sri Lankan vein graphite powder as a filler. This study reports mechanical, chemical and thermal properties of vein graphite powder sourced from Bogala mines, Sri Lanka. Five varieties of graphite powder samples were chosen to investigate their potential for application and each were characterized through Thermal Constant Analyzer, Differential Scanning Calorimetry, and Ultrasonic pulse-echo method. The ultrasonic method was adopted to obtain measurements of the Poisson's ratio (ϑ), Young's modulus (E), and Shear modulus (G) of the graphite powder samples. Highest value of thermal conductivity, volumetric heat capacity, and thermal diffusivity was reported from the grade of graphite powder possessing larger particle size. The study also focused on the improvement of the mechanical, curing, and thermal properties of vein graphite filled cushion compounds. The results showed a decrease in tensile strength with the graphite powder content. Maximum torque and the cure time were not significantly changed with the graphite particle content. Furthermore, results revealed a 66% of increase in thermal conductivity at the 10% of graphite particle addition to the compound relative to the unfilled cushion compound. It was observed that tensile strength decreased (with increased hardness) due to low interfacial adhesion and air gaps present between graphite particles and the compound. Furthermore, Dynamic mechanical analysis was performed on the vein graphite filled solid tire compounds to investigate the interaction between graphite and the polymer matrix. Next, an empirical equation, derived from the relationship between theoretical and experimental thermal conductivity values, was established to model the for graphite-iii filled solid tire compound. This equation is a valuable tool for estimating thermal conductivity within the 0-10% graphite filler loading range. Then, a comprehensive tensile test and thermal conductivity test simulations were carried out using Abaqus software and compared the obtained results with experimental data, which was observed to have reasonable correlation.
item: Conference-Abstract
Effect of vein graphite powder on dynamical properties of solid tire vulcanizate
(Department of Materials Science and Engineering, University of Moratuwa., 2023-12-14) Somaweera, D; Abeygunawardane, GA; Weragoda, SC; Ranatunga, S; Buddhima, P; Indeewari, A; Gurusinghe, Y; Konalingam, K
In the construction of solid resilient tires, three layers named tread, cushion, and base are integrated. The cushion, situated in the middle, not only contributes to a comfortable ride but also plays a crucial role in mitigating heat buildup under heavy loads. This study aims to optimize the properties of the cushion compound in solid tires by incorporating Sri Lankan vein graphite powder as a filler. This study investigates the dynamic properties of graphite-filled solid tire compounds under frequency sweep and strain sweep. Frequency sweep was given at 100°C and 10% strain. Complex viscosity of both unfilled and graphite-filled compounds exhibits shear-thinning behavior at lower frequencies, transitioning to Newtonian behavior at higher frequencies. Graphite loading influences these properties, with the 2% graphite-filled compound demonstrating the highest shear-thinning behavior and viscosity. The complex shear modulus (G*), inversely proportional to viscosity, decreases with graphite loading, with the 2% graphite-filled compound exhibiting the highest modulus. Storage (G') and loss (G'') moduli, representing elastic and viscous behavior, are influenced by graphite loading, mirroring the complex shear modulus trends. The damping factor, indicating energy dissipation, decreases with frequency and increases with graphite loading. Strain sweep analysis reveals linear behavior at low strains, transitioning to non-linear behavior beyond a critical strain, influenced by graphite content. The 10% graphite-filled compound shows distinctive behavior, exhibiting the highest damping factor at both low strains and in the entire frequency range. Overall, the study provides comprehensive insights into the viscoelastic characteristics of graphite-filled solid tire compounds, crucial for optimizing tire performance.
item: Conference-Full-text
Mechanical and Thermal Characterization of Sri Lankan Vein Graphite Powder
(IEEE, 2021-07) Somaweera, D; Abeygunawardane, GA; Weragoda, S; Vigneswaran, S; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
Graphite is being highly used nowadays in synthesizing graphene; largely exploited in synthesis of nano-composites in different forms. Crushed graphite can also be used in its powder form to synthesize beneficial particulate based composite. Besides, properties of vein graphite in its powder form is scarcely found in the literature. This study reports mechanical and thermal properties of vein graphite powder sourced from Bogala mines, Sri Lanka. Five varieties of graphite powder samples were chosen based on the specific industrial requirements and each were characterized through Thermal Constant Analyzer, Differential Scanning Calorimetry, and Ultrasonic pulse-echo method. The later method was adopted to obtain measurements of the Poisson's ratio ( ϑ ), Young's modulus (E), and Shear modulus (G) of the graphite powder samples. Highest value of thermal conductivity, volumetric heat capacity, and thermal diffusivity was reported from the grade of graphite powder possessing larger particle size. The reported properties of the vein graphite powder will be convenient to material scientists in synthesizing graphite particle-based composites and to predict their overall performance numerically as well as experimentally.