A three dimensional implicit finite element damage model and its application to single-lap multi-bolt composite joints with variable clearance

Numerical failure assessment of multi-bolt FRP composite joints with varying sizes and preloads of bolts

Vibro-acoustic modulation (VAM)-inspired structural integrity monitoring and its applications to bolted composite joints

A detailed interpretation of load distribution in composite single-lap bolted joints is presented based on theoretical, experimental and numerical investigations. Modified instrumented bolts (MIBs) were used to measure bolt shear loads consisting of the bolt bearing load and the friction force between the laminate and nut. The bolt-load carrying mechanism in single-bolt joints and the load transfer mechanism in multi-bolt joints with various tightening torques and bolt-hole clearances were revealed based on theoretical and numerical analyses and validated against experimental results. The load transferred by each bolt in a multi-bolt joint was determined with greater fidelity, and the load distributions obtained using a three-dimensional finite element (FE) model and a spring-based method were compared. The load distributions obtained from the established 3D FE model were found to be identical to those obtained using the spring-based method; the bolt-hole clearances significantly impacted the load distributions, but the effects of the bolt tightening torques on the load distributions could be ignored.

An interpretation of the load distributions in highly torqued single-lap composite bolted joints with bolt-hole clearances

Modeling on bearing behavior and damage evolution of single-lap bolted composite interference-fit joints

A study of intra-laminar damage in double-lap, multi-bolt, composite joints with variable clearance using continuum damage mechanics

The nonlinearity of fibre-reinforced polymer (FRP) composites have significant effects on the analysis of composite structures. This article proposes a phenomenological intralaminar plasticity model to represent the nonlinearity of FRP composite materials. Based on the model presented by Ladeveze et al., the plastic potential and hardening functions are improved to give a more rational description of phenomenological nonlinearity behavior. A four-parameter hardening model is built to capture important features of the hardening curve and consequently gives the good matching of the experiments. Within the frame of plasticity theory, the detailed constitutive model, the numerical algorithm and the derivation of the tangent stiffness matrix are presented in this study to improve model robustness. This phenomenological model achieved excellent agreement between the experimental and simulation results in element scale respectively for glass fibre-reinforced polymer (GFRP) and carbon fibre-reinforced polymer (CFRP). Moreover, the model is capable of simulating the nonlinear phenomenon of laminates, and good agreement is achieved in nearly all cases.

https://iopscience.iop.org/article/10.1088/1757-899X/87/1/012071/pdf

A phenomenological intra-laminar plasticity model for FRP composite materials

This paper investigated the fatigue damage coupling of composite laminate and metallic plate in multi-bolt joint. A progressive fatigue damage model for composite laminates and a modified Lemaitre damage model for metal material were developed. A phenomenological elastoplastic constitutive model was used to describe the in-plane shear nonlinearity of composite lamina. A formula for calculating the energy release rate of the low cycle fatigue was derived based on spherical tensor and shear tensor decomposition of the stress. The developed models were validated by the experimental results of a double-lap single-bolt metal-composite joint and were employed to simulate the fatigue damage of a double-lap, multi-bolt metal-composite joint. The result indicates that fatigue damage will harden the materials nearby the bolt region of the metallic plate for a multi-bolt joint structure when suffering to cyclic loads. This hardening behavior results to a transfer of bolt loads towards the harden region, which intensifies bearing damage and reduces tensile stress in the composite laminate, and improves the fatigue life of composite laminates fail in tensile mode.

/pdf/the-effect-of-metal-on-composites-fatigue-damage-in-mixed-5azp55u32p.pdf

Yinhua Zhou

Papers

A three dimensional implicit finite element damage model and its application to single-lap multi-bolt composite joints with variable clearance

A study of intra-laminar damage in double-lap, multi-bolt, composite joints with variable clearance using continuum damage mechanics

A phenomenological intra-laminar plasticity model for FRP composite materials

The Effect of Metal on Composites Fatigue Damage in Mixed Structure