Assessment of Beneficial Effects of Interference-fit in Pin-loaded FRP Composites

Abstract

Interference-fit pin connections have wide applications ranging from aerospace structures to electric hardware systems and the telephone industry. In order to derive the maximum benefit by the use of interference-fit pin in all such applications, a complete understanding of their behavior in the regions of joints is essential. This paper deals with the study of various beneficial effects of interference-fit pin-loaded FRP composite laminates. Three-dimensional finite element models have been created to simulate interference-fit pin-loaded joints in various composite laminates. Non-linear contact analyses have been performed to study the effects of interference for different material cases on (a) circumferential edge stresses, (b) stresses across the weakest section (i.e., net-tension plane), and (c) the out-of-plane stresses around the hole periphery. It is observed that interference with specific value for each material case and laminate configuration is beneficial for better load carrying capabilities. Suitable interference for improved performance has been evaluated and recommended for each case. It is also emphasized that by interference-fit fatigue life of the joint can be improved.

An experimental and numerical study on the interference-fit pin installation process for cross-ply glass fiber reinforced plastics (GFRP)

“…The end of specimen has been fixed on the X and Y-direction by considering mechanical clamping on the experimental set-up. In the analysis, the pin drives the hole toward the bottom surface of the GFRP specimen, and contact area between GFRP and the hole has a friction coefficient of 0.1 to simulate the real situation [13,28]. The total driving distance was set at 10 mm which is enough to penetrate the GFRP specimen, and has been divided into 400 sub-steps with same driving distance at each sub-step.…”

“…They reported that FE model required considering frictional contact condition and material nonlinearity to simulate the behavior of the composite joint accurately. Pradhan and Babu [13] performed non-linear contact analysis to study the effects of interference for different material cases. They formulated 3-D FE models to investigate the effects of interference-fits in pin-loaded laminates and considered friction between the pin and the hole surface to simulate the real situation.…”

“…Due to the reduced peak circumferential stress at the edge of the hole, the interference-fit joint reduced the oscillatory stresses and increased the fatigue life of the joints. Pradhan and Babu [13] conducted non-linear contact FE analyses to study the effects of interference-fit ranging from 0.0002% to 0.006% on the stress distributions in the vicinity of the hole for the various composite material cases. It was reported that suitable interference-fit for improved performance was evaluated for specific geometries, loading and material cases.…”

“…The allowance of interference fit has been well developed for many standard applications to specific metallic materials and the diameters of joints. This interference-fit technique has been adapted to the composites and some studies showed the positive results despite of the concerns of potential composite hole damage [6,[11][12][13][14][15][16][17]. The effect of interference-fit of 0.02% and 0.04% to the stress distribution in orthotropic pin-loaded composite laminates has been studied by Di Scalea et al [5] using a two-dimensional (2-D) finite element analysis (FEA) and Digital Speckle Pattern Interferometry (DSPI) on a glass fiber reinforced composite (GFRP) crossply laminate.…”

Effect of interference fit size on local stress in single lap bolted joints

“…Jiang et al 8,9 have developed a two-dimensional axis-symmetric finite element (FE) model to simulate the interference fit bolt insertion process, and then analyzed the deformation and residual stress distribution around the hole. For interference fit fastened structure subjected to an external load, the studies [10][11][12][13][14][15][16] were sufficient, but they only considered the stress analysis in the loading stage and lacked the simulation in the fastener installation stage. Usually, an even-distributed residual compressive stress was directly given at the beginning of loading in those studies.…”