How Does Strength Testing of Double-Curved GRC Panels Differ from Flat Panels? Curved Surface Mechanics and Qinglong Group's Testing Technology System

The strength testing of double-curved GRC panels differs fundamentally from that of flat panels in three essential aspects—"loading method, failure mode, and evaluation criteria"—requiring specialized testing methods. Based on 28 years of research, Qinglong Group has established a dedicated testing system for curved GRC: profiled loading heads are used to simulate actual loading conditions, full-field strain measurement is performed through Digital Image Correlation (DIC) technology, and finite element inversion is combined to analyze the true strength. In the double-curved roof testing at the Hainan International Convention and Exhibition Center, it was found that the actual load-bearing capacity of curved panels is 1.8 times that of flat panels, but failure is more sudden. Scientific testing is the foundation for the safe application of curved GRC.

The loading method must simulate real conditions. Flat panels commonly use three-point bending, while curved panels require multi-point coordinated loading with a hydraulic servo system. We have developed specialized fixtures for curved surfaces with a load-holding accuracy of ±1%. At the Nanning Testing Center, double-curved panel testing employs 32-point loading to reproduce the wind pressure distribution.

Failure mode analysis is more complex. Curved panels exhibit coupling between membrane stress and bending stress, and failure often begins at the edges. Qinglong Group uses acoustic emission technology to monitor damage evolution and provide early warning of failure precursors. CT scanning is used to analyze the propagation patterns of internal defects.

Evaluation criteria need to be re-established. Safety factors for curved panels should be appropriately increased, with stricter deformation control. We participated in formulating the "Testing Code for Curved GRC," promoting industry standardization. Scientific testing safeguards curved-surface applications.