Fig. 1. Roadmap of warping detection and cracking prediction system

Fig. 2. Software architecture of warping detection and cracking prediction in LDM

Fig. 3. Algorithm flow and detection principle. (a) Coordinate system calibration and point cloud data pre-processing flow; (b) in‐situ detection principle

Fig. 4. Definition of warping angle

Fig. 5. Two warping detection schemes. (a) Rotary slicing planes and intersecting lines; (b) parallel slicing planes and intersecting lines; (c) rotary slicing planes and parallel slicing planes were combined

Fig. 6. Algorithm flow of warping detection

Fig. 7. Schematic of the variation in warping angle

Fig. 8. Cracking prediction algorithm flow

Fig. 9. Cracking affected area determined by rotary slices. (a) Rotary slices; (b) intersecting line with the largest warping angle and four nearby intersecting lines

Fig. 10. Warping detection experiment. (a) Surface warping; (b) point cloud data after pre-processing; (c) reconstructed surface; (d) obtain the intersection lines by rotary slicing planes; (e) obtain the intersection lines by parallel slicing planes

Fig. 11. Experiment result of cracking prediction. (a) Variation trend of Q_n and K; (b) warping angle in cracking affected area at layer 51; (c) variation of warping angle at layer 51; (d) cracking at layer 55