Influence of Manufacturing Processes on the Structural behavior of Truck Frame Rail Sections
2022-01-0914
03/29/2022
- Event
- Content
- The sequence of manufacturing processes involved in the making of ladder shaped truck frame rail assembly leave certain amount of manufacturing and assembly imperfections in the form of plastic deformation and residual stresses in some areas of frame rail ‘C’ sections. The plastic deformation and the resulting residual stress should not be allowed to cross the safer limit as it would affect the structural behaviour of the frame rail while interacting with the externally induced loading stresses from extreme road operating conditions. If the combined stress level crosses the yield limit of the frame material, it may lead to premature failure of frame rail much before it gives the expected life. One such manufacturing induced premature failure in a truck frame rail assembly during proving ground trials was studied in detail using experimental analyses and presented in this paper. As part of this study, the local material crowding due to plastic deformation occurring at certain sections of frame rail and the loss of uniform surface contact with the nearby part that gets assembled with the frame were studied in detail. Kink bending process is normally used to get wider opening in the frame front end for bigger engine and its cooling system packaging. The kink bending process employed on already formed and bolt hole punched C section frame rail leads to further plastic deformation and material crowding around the bolt hole located near the kink bend area of the frame flange. Due to this plastic deformation, the bolt hole loses its shape and its surface is imbibed with unfavourable residual stresses. 3D Scanning techniques and XRD techniques were employed to assess the extent of frame bolt hole surface deformation and the residual stresses around the bolt hole surface respectively. It was observed from the study that there is significant loss of frame surface contact around the bolt joint located in the kink bend area and the presence of tensile residual stresses - crossing the yield limit of the material on the bolt hole surface. All these imperfections lead to early initiation of frame crack on the bolt hole surface during proving ground trials. The above failure analysis clearly indicates that the manufacturing imperfections in the form of plastic deformation and unfavourable residual stresses alter the structural behaviour of frame rail assembly even during vehicle normal operating conditions. From this study, it is inferred that any automotive designer should look for critical areas where certain manufacturing processes tend to introduce manufacturing imperfections and eliminate those processes or at least avoid the bolt holes/bolted joints located in those critical areas of frame rail assembly to avoid premature failure of truck load bearing structures. Key Words: Plastic deformation, Residual stress, 3D scanning technique and XRD technique
- Citation
- K, C., KR, B., and Gopal, G., "Influence of Manufacturing Processes on the Structural behavior of Truck Frame Rail Sections," SAE Technical Paper 2022-01-0914, 2022, .