Buckling Test of Composite Materials

Composite materials are widely used in aerospace, automotive manufacturing, and other fields thanks to their high strength and light weight. In actual service, however, composites may buckle under compressive loads, and such buckling can affect structural stability and safety. Buckling testing of composites to understand their strain distribution during buckling is therefore of great significance.

1. Testing Process

To measure the strain distribution of the composite during buckling, the test team chose the Haytham monocular 3D video extensometer. In the test, the composite specimen was mounted in the compression testing machine and loaded gradually until buckling occurred. The extensometer continuously photographed the specimen surface with a monocular camera and processed the captured images using digital image correlation (DIC) technology to compute the 3D strain distribution on the surface.

Throughout the test, the non-contact measurement of the Haytham monocular 3D video extensometer enabled accurate capture of the deformation changes of the composite during buckling. Unlike conventional contact strain gauges, the device covers the entire specimen surface and provides comprehensive strain data without disturbing the natural buckling behavior of the specimen. Through real-time monitoring, the device recorded the strain changes of the composite under different loads, capturing the strain concentration regions especially at the instant buckling occurred.

2. Test Results

The test results show that the Haytham monocular 3D video extensometer successfully captured the evolution of the strain distribution of the composite during buckling. The data show that strain was evenly distributed over the specimen surface in the early stage of buckling, but as the load increased, strain concentration began to appear in local regions, eventually leading to buckling. The post-buckling strain data further show that the strain concentration regions of the specimen coincided closely with the buckled locations, verifying the high-precision measurement capability of the device in capturing complex deformation. These data provide important support for analyzing the buckling behavior of composites and their performance in practical applications.