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An insight into mode II fracture toughness testing using SCB specimen
Author(s) -
Bahrami Bahador,
Ayatollahi Majid R.,
Sedighi Iman,
Yazid Yahya Mohd
Publication year - 2019
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/ffe.13069
Subject(s) - materials science , fracture toughness , composite material , finite element method , fracture (geology) , stress intensity factor , polymethyl methacrylate , stress (linguistics) , toughness , mode (computer interface) , stress field , compact tension specimen , structural engineering , fracture mechanics , polymer , crack growth resistance curve , crack closure , engineering , linguistics , philosophy , computer science , operating system
The effect of friction forces between the test specimen and its bottom supports on the mode II fracture toughness values obtained using the semicircular bend (SCB) specimen is investigated. First, a number of experiments were conducted on SCB specimen in order to determine the mode II fracture toughness of polymethyl methacrylate (PMMA) according to the conventional approaches available in the literature. Three different types of supports that have been frequently employed by researchers in recent years were used to evaluate the effect of support type on the fracture loads. It was found that the friction forces between the supports and the SCB specimen have a significant effect on the value of mode II fracture toughness measured using the SCB samples. Then, the specimen was simulated using finite element method for more detailed investigation on the near crack tip stress field evolution when friction forces increase between the supports and the SCB specimen. The finite element results confirmed that the type of support affects not only the stress intensity factors K I and K II but also the T‐stress. The experimental and numerical results showed that the use of the crack tip parameters available in literature for frictionless contact between the supports and the SCB specimen can result in significant errors when the mode II experiments are performed by using the fixed or roller‐in‐grove types of supports.