混凝土四点弯曲检测 - 新拓三维技术（深圳）有限公司

Concrete four-points bending inspection

Inspection purpose

Four-points bending experiment of large concrete specimen were carried out to measure the surface displacement field, strain field crack growth trend.

Inspection scheme overview

The measurement area of system is 2000mmX1500mm, two industrial cameras (9 million pixels, 9 frames) are used to capture speckle patterns on the surface of specimen in real time during the compression process, through camera calibration, stereo matching and 3D reconstruction, the 3D coordinates, displacement field and strain field of the object surface are finally obtained.

Inspection process

（1）Preparing speckle pattern on the surface of specimen.

（2）Setting up camera position and calibrating camera internal and external parameters.

（3）Concrete four-points bending, cameras collect data synchronously.

（4）Data analysis.

Data analysis

（1）Displacement field: the displacement field increases gradually from left to right.The observation area is located at the upper and lower left chucks. The displacement near the inner of specimen is larger and the displacement near the outer side of specimen is

smaller, which is consistent with the theoretical expectation of the four-point bending experiment.

（2）Strain field: the regional strain field of cracks is larger than that non-cracks, and the wider the cracks are, the larger the strain value is.

DIC measure the displacement value

DIC measure the strain field

（3）Crack width calculation: through the function of point to point distance, the crack width of the two areas can be measured to be 0.36mm and 0.17mm, respectively. The bigger the strain is, the wider the crack is.