Structural integrity of bolted joints for pultruded GRP profiles
The first part includes the evaluation of the 10 single-bolted and the 5 multi-bolted double lap-joint test series that appeared before 2001. This identifies that the 15 test series, from 10 centres, are often different because the researchers chose different parameters to study. Of the 800 concentric strength tests 640 were single-bolted and 160 were multi-bolted. It is noteworthy that few of these previous tests include environmental conditioning of the joints. A review of design methods is given in this part of the thesis. This shows that significant joint test data is required to appraise SI design methods for PFRP bolted joints, such as presented in the EUROCOMP Design Code and Handbook of 1996 and in 1981 by Hart-Smith. The EUROCOMP simplified and rigorous methods are expected to be generic and involve damage tolerance to increase the strength of the joint design. It is further found that application of these methods requires Finite Element (FE) stress calculations for the target analysis due to bolt bearing, and for the source analysis, for multi-bolted joints, to determine the bolt load distribution and by-pass loads. Parts two and three of the contribution from the author are combinations of experimental and FE analysis work that focuses on the target and the source problems, respectively.
Presented in part four is a preliminary appraisal of the EUROCOMP simplified design method and the Hart-Smith design method. The EUROCOMP method is shown to possess deficiencies, via a critique by Lancaster University, which indicates that it cannot be used in practice. By taking information from the multi-bolted joint test series in part three the author constructs semi-universal design charts using the Hart-Smith method, which can be used to design joints with changing geometry. An important finding from this preliminary appraisal is that the SI design methods are difficult to apply since they require lots of physical test data and relevant and reliable stress results from FEA.