Effects of squeeze force on static behavior of riveted lap joints

Abstract

To study the effects of the squeeze force used in the rivet installing process on structural behavior of the riveted lap joints, three-stage finite element simulation and workshop experiment of single-row countersunk riveted lap joints were implemented. Force-displacement curves and explicit configuration after various processes were obtained from both methods. Additionally, stress/strain fields were obtained from finite element analysis, and strain values at specific positions were measured by micro strain gauge during the experiment. Based on the consistency of the results, stresses on the edge of dangerous holes, load transmission, and secondary bending of joints under tensile load were analyzed. The result shows that increasing squeeze force does not have a significant influence on joint stiffness but results in a slight decrease in joint strength. Greater squeeze force introduces greater residual stress around the hole, and the maximum principal stress around the hole becomes greater tensile stress instead of initial compressive stress introduced by riveting process, thus causes weaker static strength. It is also shown that under static load, breakage occurs in the outer sheet at the end hole due to the largest load transmission and secondary bending, whereas these two aspects not only depend on the rivet installation squeeze force but also depend on the size of the exterior tensile load.

A review on solid riveting techniques in aircraft assembling

“…This linear relationship is effective for predicting the fatigue properties of joints. Zhou et al [35] found that clamping the interference-fitted joint exhibits higher fatigue lives than that of clamping of the cold-expanded and interferencefitted joint at low stress levels, while at high stress levels, the results are opposite, which explains exactly the results obtained by Huan et al [24], who concluded that the influence of interference-fit on fatigue properties of joints is closely related to the stress level. Skorupa et al [38] concluded that the interference-fit between the rivet and the hole can effectively compensate for the notch effect under the axial loadings to improve fatigue properties of riveted joints.…”

“…Most of studies have focused on the influence of squeeze force on residual stress/strain distribution and SB stresses after rivet installation. Huan et al [24] conducted experiments of single-row countersunk riveted lap joints to investigate the squeeze force effect on static behaviour of the riveted lap joints. The joint stiffness became nonlinearly smaller with the gradually increased tensile load, while the effect of squeeze force on joint stiffness was not significant.…”

“…Interference fit is one of the important production variables to improve the fatigue life of riveted joints. The latest research is mainly aimed at the uniformity of interference fit, the mechanism of improving fatigue performance of interference fit and the influencing factors of interferencefit [24,31,35,38]. Skorupa et al [31] found that the coefficients of interference between rivets and holes and friction between joints were linearly correlated with riveting parameters (mainly squeezing force).…”

“…Driven by the requirements of high performance and lightweight, new structures, process and materials have been introduced into the assembly [51]. To enhance the strength of the joint, other connection methods, such as bonding, are integrated with riveting, which is the so-called hybrid joint [24]. In addition, electromagnetic riveting technology has been applied to solve the challenge posed by the introduction of titanium alloys and composite materials [46].…”

Novel Design of a Joint with Translational Freedom for Propellant Tank Anti-Slosh Baffle System

“…It was found that if the rivet length and diameter increase, the amount of squeeze force needed to drive a rivet increases. [7] experimentally evaluated the structural behaviour of riveted lap joints with squeeze force. The study comprised of static strength experiments and FE analysis.…”