Generalized Linear Elastic Fracture Mechanics: An Application to a Crack Touching the Bimaterial Interface

2010 ◽  
Vol 452-453 ◽  
pp. 445-448 ◽  
Author(s):  
Luboš Náhlík ◽  
Lucie Šestáková ◽  
Pavel Hutař ◽  
Zdeněk Knésl

In the contribution the limits of the validity of classical linear elastic fracture mechanics are extended to problems connected with failure of composite structures. The work is focused mainly on the case of a crack touching the interface between two different materials, two different constituents. The approach suggested in the paper facilitates the answer to the question what is the influence of particle (in particulate composite) or layer (in laminates) on crack propagation through bimaterial interface. Different composite (bimaterial) structures are considered: layered composites and composites reinforced by particles. The presented approach follows the basic idea of linear elastic fracture mechanics, i.e. the validity of small scale yielding conditions is assumed, and has a phenomenological character.

Author(s):  
Lallit Anand ◽  
Sanjay Govindjee

This chapter introduces the basics of linear elastic fracture mechanics. It starts by recalling the asymptotic elastic crack tip solutions and the concept of stress intensity factors for Mode-I, Mode-II, and Mode-III loading. The concept of critical stress intensity factor is next introduced as a model for fracture under small scale yielding conditions. In this context the limits of linear elastic facture mechanics are discussed. Further, methods and requirements for fracture toughness testing are discussed.


2021 ◽  
Author(s):  
Xiaoliang Jia ◽  
Zhiwei Chen ◽  
Fang Ji

Abstract High strength steel is usually used in fabrication of hydrogen storage vessel. The fracture toughness of high strength steel will be decreased and the crack sensitivity of the structures will be increased when high strength steels are applied in hydrogen environment with high pressure. Hence, the small cracks on the surface of pressure vessel may grow rapidly then lead to rupture. Therefore, this paper makes a series of research on how to evaluate the 4130X steel hydrogen storage vessel with fracture mechanics. This study is based on the assumption that there is a semi-elliptic crack on internal surface of hydrogen storage vessel. First of all, based on linear elastic fracture mechanics, the stress intensity factors and crack tolerance of 4130X steel hydrogen storage vessel have been calculated by means of finite element method based on interaction integral theory and polynomial-approximated approach from GB/T 34019 Ultra-high pressure vessels. Then, a comparative study has been made from the results of above methods to find out the difference between them. At last, the fatigue life of a 4130X steel hydrogen storage vessel has been predicted based on linear elastic fracture mechanics and Paris formula. The calculation methods and analysis conclusion can be used to direct the design and manufacture of hydrogen storage vessel.


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