The optimized design parameter of the car support jack bar is crucial in ensuring the safety of maintenance activity. Improper design of the bar and pinhole could induce the jack bar's failure when enduring the high loading of the car. This paper presents the response surface optimization on the design parameter of the car jack bar using finite element analysis. Three factors: outer diameter (A), pinhole diameter (B), and bar thickness (C), and two responses which are Von Mises stress (Y1) and displacement (Y2) of the jack bar, were considered in the optimization study. The design of the numerical experiment was constructed using the central composite design (CCD). The results revealed that outer and pinhole diameters are the two most significant factors in the responses. The changes in outer and pinhole diameters crucially affected the Von Mises stress and displacement of the jack bar. The optimized factors suggested in the optimization software are 49.79 mm outer diameter, 21.70 mm pinhole diameter, and 5.85 mm bar thickness. The application of optimized factors yielded the minimum responses that are 45.23 MPa Von Mises stress and 0.022 mm of displacement for the car jack bar. The optimization findings are expected to be useful for the engineer in designing the high-reliability car jack bar.
