Investigation of stress distributions of chrome coated polyamide materials under thermal loads using finite element method

Competition has come to the forefront in many different fields and engineering studies with the development of the technology, which is still continuing today. This competition is not only between the product-service providers but also between the material and the properties of the products being produced. Starting from this point of view, we can assume that better processes and better materials can always be used to create the same product. However, there are no infinite options to choose better materials and better processes. Because of this assumption, most of the time it is being possible to gain more output with less input by the help of the changes made on existing material; hence, coating techniques are examples of this. With the coatings to be made on the materials, surfaces with different characteristics and/or dimensions can be obtained different from the main material. With such applications, the product with the desired properties of both materials, including the coating material and the coated material can be produced. In this thesis, metallic coatings on plastic materials were examined. Stress distributions due to thermal expansion under thermal load in relation to layer thickness in metallic coatings were investigated. In the study, models were created with the names of roll bar, beam, circle and handle. The models were obtained by adding layers of copper, nickel and chromium, respectively, on the base material polyamide. Polyamide main material is modeled with solid elements while shell elements are used for coatings. The contact of each layer with the lower surface is assumed to be ideally adherent. 3D models has been created with SolidWorks software and the finite element analysis models has been created within ANSYS Workbench software where thermal loads has been applied. In all models, different geometry and analyzes were made with different thickness variations of each layer and the effect of change in layer thickness on the stresses on all layers was investigated. Using the results obtained, Von Mises stress graphics are given for each model despite of the increase in temperature. In addition, the shape changes due to temperature increase are presented graphically. As a result, the layer having the greatest impact on varying stress distribution due to layer thickness is determined for each model. According to the results obtained, as the thickness of the coating increases, the stresses are generally reduced. However, if there are discontinuities in the shape like corners or curves in geometry, it is observed that the stress distributions are bigger in these regions.