Assessment Of Real World Bolted Joints By Combining FEA With VDI Guidelines

Real world bolted connections are subjected to axial, bending and transverse working loads which are mostly difficult to ascertain purely by hand calculations and FBDs. The VDI 2230 document which is largely followed across the industry for bolted joint assessments, assumes that the load data is readily available to the users. However, that is not always the case. This paper tries to address this aspect of bolted joint assessment by providing physics based and validated guidelines to ascertain these loads using Finite Element Tools. Prying effect may be obvious in simple cases, however quantifying this effect in real life problems is quite challenging. Authors have suggested simple, but effective method, to quantify this prying effect using FEA. Related to bending load on bolts, VDI explains that only a fraction of total bending moment observed by a joint is seen by the bolt, which is related to the relative bending resilience of members and bolts. The VDI document assumes that the members have standard shapes and are simple prismatic discs. This is a far cry from the real world bolted joints. Using FEA, bending loads are accurately explained in this study. Similarly, the effect of load introduction planes, though captured in VDI, may be very challenging and subjective to apply on actual bolted joints. The use of FEA to accurately capture this effect is also explained. Finally, the paper also explains how to use this data generated as input into SR1 software which is an industry standard tool based on VDI. The paper intents to enable the readers to make better and informed evaluations of their bolted joints by deploying techniques outlined in this body of work.