Papers by Keyword: Mechanical Fastening

Abstract: For a set of applications, thin metallic sheets are used in fibre composite materials to reach higher load introduction capacities. The paper deals with a simplified generic problem of this kind. The main subject is the comparison of results of three types of models, namely, a 1D-, 2D- and a 3D version. What can be shown is the fact that results are quite similar with respect to behaviour along the loading direction, but very different in the actual values.

Abstract: Pure adhesive bond of FRP to concrete is not only weak but also unreliable in a long term. This problem can be effectively overcome by a newly developed bond enhancement system the hybrid bonded FRP system (HB-FRP) in which small mechanical fasteners are used to augment the bond. In this paper, the bond behaviors of EB-FRP and HB-FRP joints were experimentally investigated by employing the single shear pull-off test on three EB-FRP and seven HB-FRP specimens with different bond lengths. Experimental testing is reported for characterization of the interfacial bond of the HB-FRP system.

Abstract: Pure adhesive bond of FRP to concrete is not only weak but also unreliable in a long term. This problem can be effectively overcome by a newly developed bond enhancement system the hybrid bonded FRP system (HB-FRP) in which small mechanical fasteners are used to augment the bond. In this paper, theoretical modeling is reported for characterization of the interfacial bond of the HB-FRP system. Local bond-slip model involving adhesive and mechanical mechanisms is proposed. Based on the basic bond-slip model, load-slip response, ultimate bond strength, and effective bond length of the HB-FRP bond interface are obtained by analytical or numerical solution. Good agreement between the analytical and experimental results indicates that the proposed bond-slip model can well predict bond behaviors of HB-FRP joints.

Abstract: The aluminium alloy and mild steel sheets were joined with mechanical clinching. Deforming behaviour of the two sheets during the clinching was observed from finite element simulation and an experiment to avoid defects. The fracture of the upper sheet, necking and separation are caused by the small upper sheet thickness in the thick total thickness, the small lower sheet thickness in the thick total thickness and the small lower sheet thickness, respectively. The joining range for the combination of the upper aluminium alloy sheet of and the lower steel sheet of is larger than that of the reverse combination. The effect of the difference between the flow stresses of the two sheets on the deformation behaviour was examined.

Abstract: The residual stresses around clearance-fit mechanical fasteners have been found to be similar to those around cold expanded holes where compressive hoop stresses close to the fastener hole are balanced by far-field tensile stresses. This compressive zone has been shown to prolong fatigue lifetimes around fastener holes. Constant amplitude fatigue loading was applied to single plate rivet specimens for varying numbers of cycles to investigate the redistribution of these stresses after fatiguing. Synchrotron diffraction was used to map the evolution of the residual stresses around the rivets. Little change in the hoop stress local to the rivets occurred until visible fatigue cracks were observed suggesting that relaxation of these stresses is due to the cracks rather than their cause.

Abstract: The use of composite materials in many engineering structures has increased recently. The structures are jointed together by single or multiple bolted mechanical fastening to transfer the loads from one member to another. Applications of such joints require adequate knowledge of stress distribution in the vicinity of the boundary of pin hole. In this study, stress analysis is conducted with finite element method to study the stress distributions in the vicinities of both single-pin and multi-pin loaded holes of multi-axial warp knit fabric composite laminates. The perfect fit condition and contact with friction between the pin and hole without lateral constrain are assumed in the analysis. Effects of friction, stacking sequence, ratio of edge distance over hole diameter, ratio of width over hole diameter, number of pins, number of rows, number of column and hole patterns are evaluated. The results show they have a significant influence on joint performance.