Bolted joints are the most used joints in automotive suspension assemblies. They are expected to retain the strength over the course of useful life of the vehicle and contribute to durability in a big way through reduction of stress amplitudes. Any sort of loosening or slip or breakage in these joints can lead to noise or catastrophic failures.
In the past, such issues were addressed through thumb rules and design guidelines. However, with the focus on first-time right tests with reduced validation time it has become important to upfront predict the suspension joint integrity through simulation.
Toward this objective, a novel approach was developed to simulate the suspension joint integrity for bolted joints. This approach considers various parameters like bolt preload, tolerance stackup of the parts in the joint, coefficients of friction of various interfaces, quality of contact and effect of deformation at the thread interface on joint integrity. Also, key parameters like percentage of bolt preload utilized in compression of bolted joint and contact opening values were monitored in joint integrity analysis. With the help of this method, it was possible to correlate prediction of joint slip for bolted suspension joint in vehicle durability test. Understanding of variation of joint performance w.r.t. above parameters enabled quick solutions to make the joints more robust. Thereafter this method was applied to other suspension joints in the vehicle to evaluate joint integrity in a reliable manner which was also corroborated in the test. This paper will outline and discuss in detail on above points. It will propose the method and criteria for judging bolted joint integrity.