Study of crack arrest mechanism and dynamic behaviour using arc‐bottom specimen under impacts

• Published in: Fatigue & fracture of engineering materials & structures 2020-09, Vol.43 (9), p.2040-2054
• Main Authors: Lang, Lin, Zhu, Zheming, Deng, Shuai, Niu, Caoyuan, Wan, Duanying
• Format: Article
• Language: English
• Subjects: arc‐bottom; arrest function; Computer simulation; Crack arrest; Crack initiation; Crack propagation; crack propagation speed; drop weight impact; Finite element method; fractal dimension; Fractals; Loading rate; Mathematical analysis; Propagation; Propagation velocity; Stress intensity factors; Stress propagation; Structural damage
• ISSN: 8756-758X; 1460-2695
• DOI: 10.1111/ffe.13282

In this paper, a large size trapezoidal open crack with arc‐bottom (TOCAB) configuration specimen was proposed. Experiments were carried out using 0°, 60°, 90° and 120° TOCAB specimens under drop weight impacts with loading rate from 150 to 350 GPa/s. The crack length and crack speed were calculated by using fractal method. It shows that the crack speed corrected by fractal method is more than 12% the original speed calculated using the straight length. The AUTODYN code was employed to simulate crack propagation path and crack speed. The dynamic stress intensity factors (DSIFs) were calculated using ABAQUS code. The experimental and numerical results show that all the three TOCAB specimens have arresting function on running cracks; crack propagation velocity increases with loading rates; the critical DSIFs at initiation are higher than those at propagation. The study presents how to arrest a running crack and how to protect significant structures from being completely damaged.