Study on Determining Dynamic Fracture Initiation Time for Concrete by Strain Gauge Method
FAN Hong1,3;ZHANG Sheng2;WANG Qizhi1
1. Department of Civil Engineering and Applied Mechanics, Sichuan University, Chengdu 610065, China; 2. Department of Mining Engineering, Henan Polytechnic University, Jiaozhuo 454001, China
Abstract：In testing dynamic fracture initiation toughness KId of quasi-brittle materials, such as concrete, it is crucial to determine fracture initiation time of crack tip accurately. Dynamic experiment was performed using a holed-cracked flattened Brazilian disc of concrete, which was diametrically impacted by Split Hopkinson Pressure Bar, the fracture initiation time was determined by the strain gauge method. Different sticking location of the strain gauge, different direction of the strain gauge and other factors to affect determining fracture initiation time were discussed. Based on the experiment results, the best approach is advised, the strain gauge should be stuck along the crack extension line or the vertical line to the crack at crack tip, the distance is about 3 mm from the crack tip to the center of strain gauge, and the sticking direction of the strain gauge is vertical to the crack. A formula to determine the fracture initiation time is given, which considers the sticking location of the strain gauge and thickness of the specimen.
樊鸿;张盛;王启智. 用应变片法确定混凝土动态起裂时间的研究[J]. , 2010, 29(1): 153-156.
FAN Hong;ZHANG Sheng;WANG Qizhi. Study on Determining Dynamic Fracture Initiation Time for Concrete by Strain Gauge Method. , 2010, 29(1): 153-156.
2010, Vol. 29 
