Tensile Pull-Out Behaviour and Global Sensitivity Analysis of Fastening Screws in Photovoltaic Aluminium Support...

Fastening screw connections in aluminium alloy photovoltaic (PV) support structures are highly susceptible to premature failure under wind-induced uplift suctions. This paper presents a systematic experimental, numerical, and probabilistic investigation into the tensile pull-out performance and interactive parameters of these joints. Static pull-out tests were performed to classify two typical failure mechanisms: thread stripping combined with base metal tearing (Failure Mode I) and screw shank tensile fracture (Failure Mode II). High-fidelity 3D finite element models incorporating explicit thread geometries were established, matching experimental curves with an error within 5% and accurately replicating micro-stress peeling contours. Furthermore, a multi-stage simulation loop integrating Latin Hypercube Sampling (LHS) and Response Surface Methodology (RSM) was implemented within a large-scale Monte Carlo framework to efficiently quantify parameter sensitivities under the elastic limit state. The global stochastic assessment reveals that the aluminium elastic modulus and RHS wall thickness are the primary positive controlling parameters, exhibiting high sensitivity coefficients of 0.44 and 0.40, respectively. Conversely, the profile width renders a significant negative sensitivity due to local out-of-plane flexing. These quantified indicators provide crucial structural optimisation directives for ensuring the safety of solar tracking and racking systems.