Light Truck Frame Joint Stiffness Study

Truck frame structural performance of body on frame vehicles is greatly affected by crossmember and joint design. While the structural characteristics of these joints vary widely, there is no known tool currently in use that quickly predicts joint stiffness early in the design cycle.

This paper will describe a process used to evaluate the structural stiffness of frame joints based on research of existing procedures and implementation of newly developed methods. Results of five different joint tests selected from current production body-on-frame vehicles will be reported. Correlation between finite element analysis and test results will be shown. Three samples of each joint were tested and the sample variation will be shown.

After physical and analytical testing was completed, a Design of Experiments approach was implemented to evaluate the sensitivity of joints with respect to gauge and shape modification. The results of the DOE were fitted to a response surface and brought into an Excel spreadsheet. The result is an easy-to-use Excel spreadsheet based Toolkit for evaluating joint stiffness.