Thermal Behavior of a Large-Span Continuous-Welded Stainless Steel Roof System
Abstract
The structure of the large-span metal roof system is complex, and the thermal effect at the key nodes under the thermal load of the operation is significant, leading to fatigue failure risk of load-bearing members and structural safety hazards. Existing studies on metal roof thermal performance mainly rely on laboratory static experiments and idealized numerical simulations, with limited attention paid to long-term field thermal responses of multi-layer continuous-welded stainless steel roof systems under real solar radiation. In this work, the nonlinear thermodynamic response of a large-span continuous-welded stainless steel roof (LCSR) system under a temperature field is revealed by field measurement, theoretical modeling, and finite element analysis. Field measurements show that the roof temperature gradient dominated by solar radiation leads to a maximum interlayer temperature difference of 28.4 °C, and a nonuniform distribution of 5.9 °C along the panel length direction, with thermal stress increasing linearly with ambient temperature. Based on heat conduction theory, a temperature field calculation model for the roof panel is proposed and validated against field measurements and finite element results, with maximum errors of 8.5–12.2%. Finite element parametric analysis further reveals that panel width and purlin spacing govern the thermal deformation of the LCSR system. Increasing panel width from 300 mm to 500 mm increases displacement by 175% while decreasing thermal stress by 14.2%. Increasing purlin spacing from 600 mm to 1500 mm increases displacement by 31.4% and reduces stress by 8.6%, while panel thickness has a negligible effect (<1%) on the mechanical response. This multi-method framework overcomes the limited accuracy of traditional single-parameter models in nonlinear temperature stress prediction and provides theoretical support for establishing thermomechanical coupling design criteria for large-span metal roofs.