On the Variation of Clamping Force in Bolted Double Lap Joints Subjected to Longitudinal Loading: A Numerical and Experimental Investigation

Abstract

This study investigates the variation of clamping force and its concomitant effects on the performance of bolted double lap joints subjected to longitudinal loading. Two different amounts of clamping force were applied to bolted double lap joints made of Aluminium 2024‐T3, and variations of clamping force were measured under the application of longitudinal loading. Finite element modelling was also performed to compare with experiments. The results unanimously revealed a gradual initial reduction of clamping force followed by a significant increase as the longitudinal load was increased. Also affected, was the load transfer mechanism in the joint resulting in variation of friction force between the plates, but in a different trend compared to clamping force. Finally, the key parameters have been discussed and highlighted pertaining to the performance of the joint.

Fe-Modelling of a Contact Layer Between Elements Joined in Preloaded Bolted Connections for the Operational Condition

“…Assuming the division of the model into three subsystems (B -the bolt, F -the flange element, C -the contact layer), the equation (2) can be rewritten as follows: At the assembly stage, the system is composed of only two subsystems (F and C), preloaded by the force F n (Figure 1b). Then the equation (3) is reduced to the form: (4) At the operational stage, the preloaded system is loaded by a normal external force F e . Then the loads vector p can be written as: Both in the assembly and the operational condition, by solving the system of equations one obtains the displacements vector q C :…”

“…Currently, in modelling of the contact joint in bolted connections the finite element systems are often used [3][4][5]. However, using standard contact elements available in these systems, only constant stiffness coefficients for each contact element at the contact surface can be taken into account.…”

Finite Element Modelling of a Pair of Flexible Elements Contact Preloaded and Externally Loaded with an Arbitrary Force

“…− models of the joint, in which the contact layer between the joined elements is not taken into consideration [1], − linear contact models with constant values of the contact stiffness coefficients over the entire nominal contact surface, commonly available in commercial finite element analysis systems [9,10,12,20,21,24,31,33,38,42], − non-linear contact models [5,7,13,51]. In the above-mentioned models, the possibility of taking into account the variable contact stiffness coefficients for each of the contact elements on the contact surface is not considered, which would be useful in the case of the contact analysis of the elements joined in a connection model with the experimentally defined stiffness characteristics of the contact layer between them [16].…”

Comparison between bolt clamping force and composite patches for repairing aircraft structures of aluminum alloy 2024-T3

“…Many parameters affect life time or failure strength of bolted members. Previous research [9][10][11][12] shows that the clamping force from bolt pre-tension is the most important factor affecting the behavior exhibited by bolted joints. Numerous research have been conducted on bolted repair and parameters affecting them and their mechanical behavior.…”