FE simulation and experimental tests of high-strength structural bolts under tension

Abstract

Highlights Bolts mating with nuts of higher class can lead to a higher probability in failure  8.8 structural bolts mating with bright nuts failed by thread stripping  In the numerical simulation, influence of different material laws was small  Some discrepancy in load-displacement relationship can be observed  Numerical simulation was capable of representing the failure mechanisms -1 - FE Simulation and Experimental Tests of High Strength Structural Bolts under Tension-2 - ABSTRACTExperimental tests has been completed for high strength 8.8 bolts for studying their mechanical performance subjected to tensile loading. As observed from these tests, failure of structural bolts has been identified as in one of two ways: threads stripping and necking of the threaded portion of the bolt shank, which is possibly due to the degree of fit between internal and external threads. Following the experimental work, a numerical approach has been developed for demonstration of the tensile performance with proper consideration of tolerance class between bolts and nuts. It has been found that the degree of fit between internal and external threads has been identified as a critical factor affecting failure mechanisms of high strength structural bolts in tension, which is caused by the machining process. In addition, different constitutive material laws have been taken into account in the numerical simulation, demonstrating the entire failure mechanism for structural bolts with different tolerance classes in their threads. It is also observed that the bolt capacities are closely associated with their failure mechanisms.

Behaviour of stainless and high strength steel bolt assemblies at elevated temperatures — A review

“…European and US standards [22,23] employ temperature-dependent strength reduction factors for high strength bolts derived from a curve fitted to experimental data from tests carried out by Kirby [11]. However, there is some debate on the reliability of the codified reduction factors as some publications report that the current reduction values in the codes are not always conservative when used for other bolt types [12,37]. The curve fitting method is therefore only strictly valid for bolts similar to those used to produce the curve and thus, a wide range of tests considering various parameters and failure modes is necessarily required before extrapolating to other bolts.…”

Numerical testing of steel beam-to-column bolted extended end-plate connection with haunches

“…In literature are presented several FE models which may be adopted for the bolt. In [6] and [7] a very detailed FE model has been considered in which the entire geometry is modelled. However, for this application such a model is not appropriate due to the large number of finite elements.…”

Model Order Reduction of Bolting and Feasibility Evaluation

“…For bending analysis a load of 216.1kN [1], is applied on the bolt shank transversely, keeping the head fixed as in figure 4. The deflection is compared between theoretical and numerical deflection.…”

“…In this paper, a high-strength grade 8.8 bolt, made from low carbon steels or alloy steels, with dimensions as shown in the figure [1], in accordance with BS 4190:2001 and BS EN ISO 4014:2001, was taken into consideration. Comparison of theoretical results and numerical results has been made, for both tension and bending analysis.…”