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This paper presents experimental and numerical investigations in the single-lap, single-bolt joints of carbon fiber reinforced bismaleimides (CF/BMI) composites. In order to guide the engineering design, an optimum configuration of composite joints is determined. Effects of stacking sequence and geometry dimensions on composite joints under tensile loading are discussed to select an optimum configuration. The optimum configuration is validated by the experimental method. Quasi-static tensile tests are conducted according to ASTM D5961 to evaluate the joint stiffness, joint strength, and bearing behavior. Finite element (FE) models considering progressive failure and delamination failure are established to investigate the joint stiffness, bearing strength, damage mechanisms, and evolution of delamination damage. Results show that bearing failure accompanied with delamination caused by secondary bending is the main failure mode, indicating an expected non-catastrophic failure mode.

Structural loads, especially in-plane compression, may cause local buckling and debonding of the photovoltaic (PV) cells that are mechanically integrated with structural members and this may lead to degradation in their electrical performance. This paper proposes an approach to mitigate the strains transferred from structural members to PV cells through the partial composite action provided by low-modulus adhesives. Specimens were fabricated by bonding amorphous silicon (a-Si) PV cells to glass fibre reinforced polymer (GFRP) structural components by an adhesive layer of 0.5- or 2.0-mm thickness. Two types of adhesives were used including a two-part rigid epoxy adhesive and a low-modulus silicone adhesive. These integrations were then submitted to in-plane compressive loadings. PV cells bonded by the silicone adhesive showed no damages during loading. While for PV cells bonded by epoxy adhesives, obvious electrical performance degradations were observed, when the strain reached 0.62% or 0.23% for specimens bonded by epoxy with a layer thickness of 0.5 mm or 2.0 mm respectively. Debonding and local-buckling of the PV cells were also witnessed. Theoretical analysis was conducted to understand the strain mitigation of the adhesive as a result of the induced partial composite action. Results demonstrate that such strain differences between the GFRP and the bonded PV cell are dominated by the shear modulus and thickness of the adhesive layer as well as elastic modulus, thickness and length of the PV cell. The theoretical analysis was validated by finite element (FE) modelling and design suggestions are provided accordingly.