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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2017, Vol. 38 ›› Issue (10): 221128-221128.doi: 10.7527/S1000-6893.2017.221128

• Solid Mechanics and Vehicle Conceptual Design • Previous Articles     Next Articles

Load separation based direct calibration method for estimating J-resistance curves

WU Yuanjun, BAO Chen, HE Guangwei, CAI Lixun   

  1. School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, China
  • Received:2017-01-13 Revised:2017-05-31 Online:2017-10-15 Published:2017-05-31
  • Supported by:

    National Natural Science Foundation of China (11472228)

Abstract:

The explicit expression of P-V curves for blunt cracked Compact Tension (CT) specimens with different stationary crack lengths is proposed based on the principle of load separation.The load-displacement (P-V) curve of sharp cracked CT specimens is compared with that of blunt cracked CT specimen.The Load Separation based Direct Calibration (LSDC) method is developed to estimate the instantaneous crack length of the sharp cracked CT specimen.Any physical measurement of the crack length on the fracture surface of the broken specimen is unnecessary in this method.A group of CT specimens made of Cr2Ni2MoV steel are used to verify the feasibility and validity of the LSDC method.The results show that the J-resistance curves obtained by the LSDC method are more reasonable and accurate than those obtained by the unloading compliance method and the normalization method.The LSDC method can get critical toughness at the point of the P-V curve of sharp cracked CT specimen separating from that of the blunt cracked CT specimen,where the two specimens have the same initial crack length.The critical toughness can truly reflect the crack initiation.Compared with traditional critical toughness obtained by the intersection of 0.2 mm blunting offset line and J-resistance curves,the critical toughness corresponding to the separation point is more reasonable and has smaller data dispersion.

Key words: load separation based direct calibration method, J-resistance curves, critical toughness, Cr2Ni2MoV steel, CT specimen

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