On the optimization of Kereta Kapsul's base frame structure

A local company in Bandung, PT TREKKA, is currently developing a new public transportation system named Kapsul System. The ultimate goal of the development is to obtain a competitive public transportation system in terms of the cost of construction and operation. Kereta Kapsul is one of the product being developed. Preliminary analysis needs to be done to verify the initial design of the Kereta Kapsul. This paper presents the stress analysis and design optimization of Kereta Kapsul's upper structure consisting of a base frame and a body frame. The analysis was conducted numerically using finite element method. The analysis began with geometry and finite element modeling and was followed by the application of loads and boundary conditions in accordance with the standards used. The meshing process was carried out with first-order quadrilateral elements of 10 mm in size for the base frame structure and of 15 mm in size for the body frame. Convergent and valid finite element models were then used as models in further stress analysis. Initial design of base frame failed under compression loading as required by the standards. Design optimization has been done for five iterations and resulted in the last model with a mass of about 1100 kg with minimum safety factor of 2.7 in the worst case loading and of 2.3 on compression loading.