By Dr. Sisira Ranatunga

The Finite Element Analysis (FEA) plays a major role in developing new tyre designs to meet various performance demands

Dr Sisira Ranatunga, Fellow of the Plastics and Rubber Institute of Sri Lanka and the Secretary of The Sri Lanka Association of Manufacturers and Exporters of Rubber Products (SLAMERP).

Continuous study on “polymer composites” is a very attractive area for researchers due to increasing demand to significantly alter the base polymer properties resulting in a low-cost composite material with potentially useful properties.
Incorporation of filler into a virgin polymer will affect the melt rheological behaviour of filled composite systems and it is noted that this behaviour will be critically important in defining the processability of the composite in the manufacturing processes. Furthermore, this behaviour is important to study the mechanism by which the addition of filler influences the original polymer and to determine the combinations in which such effect occur.
Publications on composites of different polymer as the main matrix, coupled with various types of modified or unmodified fillers and reinforcements, could be found in abundance in many polymer composite journals. However, scientific studies and finite element modelling on the effect of temperature increase due to heat build-up when polymer composites are subjected to dynamic load application on stress and strainbehaviour are not substantial.
The main objective of our recent research was to develop a “ model ” to predict vulnerable failure area and stress–strain behavior of polymer composites products at different temperatures using Finite Element Analysis for dynamic load applications.

Significance of FEA

The Finite Element Analysis (FEA) is a numerical method for solving problems of engineering and mathematical physics. FEA started in the period 1940-1950 and gradually evolved as a very advanced tool with the development of computers and solving algorithms. These FEA methods are widely used in all kinds of industries to analyse the performance of various behavioural parameters in products such as materials, physical, thermal, flow behaviours coupled with metaphysical behaviours. Polymer composites exhibit a wide range of physical parameters according to their composition and manufacturing process.
When products are designed using these composites it is vital to know the final product behaviour in advance, in order to develop optimized product which will perform effectively in the intended application and also is economical to commercially produce and market.
In the application of FEA to a composite product, first we have to extract the Stress-Strain behaviour of the composite material at different temperatures. Also other parameters such as poison ratio of the composite, thermal conductivity and thermal expansion need to be measured according to the analysis type which is intended to carry out.
Accurate measurements of material parameters are very important for composite analysing in order to achieve realistic and reliable results. Proper model creation, finite element mesh, boundary conditions and appropriate material model selection to represent the real world problem correctly, also influences the results of the study. Finally proper interpretation of the results must be done to extract valuable inputs from FEA to the product design.
It is vital to validate the results obtained by FEA by comparing with actual results in a more simple simulation. After the correct validation more advanced and complicated simulations can be carried out with confidence. Optimized designs of composite products inside the simulation environment itself can be created through simulations coupled with optimization algorithms. Also advanced multi physics simulations such as product interactions with fluid materials, and product interactions with gravel like materials are carried out.

Development of tyre designs

FEA plays a major role in developing new tyre designs to meet various performance demands. Tyreside wall shape optimization methods, tyre tread pattern design and evaluation methods based on various criteria through simulations, tyrebehaviour in a moving vehicle and its effect on the vehicle dynamics are a few research areas in which FEA contributes significantly. When tyres are rotated under load, heat is generated by the rubber resulting in complex physical behaviour. This heat generation under cyclic loading can be accurately simulated by state-of-the-art FEA technology available considering strain energy density details.
Novel FEA model suggested for polymer composites in the present study can be applied to predict the most vulnerable failure area and the stress and displacement of polymer composites materials at different temperature applications.