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Fracture Process in Micro Reinforced Metal Matrix Composites
Published in Suneev Anil Bansal, Virat Khanna, Pallav Gupta, Metal Matrix Composites, 2023
Abhijeet Singh, Pardeep Bishnoi, Jeeva Chithambaram
Fracture mechanics is a branch of mechanics that studies the growth and spread of cracks in a material. It is a crucial tool for improving the mechanical component’s performance. Fracture mechanics has been used to aid in the design of components in a safe and cautious manner by identifying the conditions required to prevent component failure. It enables the design of a component while taking into account the occurrence of defects.
Molecular Origins of Toughness in Polymers
Published in Charles B. Arends, Polymer Toughening, 2020
Jozef Bicerano, Jerry T. Seitz
Within the context of fracture mechanics [2,6], the toughness of a specimen refers to the total amount of energy required to cause failure, that is, the total area under the stress—strain curve. For example, the specimen whose stress-strain behavior is shown in Fig. 1a is “tougher” than the specimen whose behavior is shown in Fig. 1b. Toughness is, in general, highly desirable. It can only be defined precisely for the behavior of a given specimen under a given set of test conditions. When a reference is made to the toughness of a polymer or other type of material rather than the toughness of a specimen, this describes the statistical average of the stress-strain behavior of a set of specimens of the material under a precisely defined set of test conditions.
An Expert System Approach to Applying Fracture Mechanics to Reinforced Concrete
Published in Alberto Carpinteri, Applications of Fracture Mechanics to Reinforced Concrete, 2018
S. E. Swartz, Y.-C. Kan, K. K. Hu
The applications of methods of fracture mechanics to structural engineering are very diverse and include: life assessment of aircraft structural components, inspectability criteria for aircraft, inspectability criteria for bridges, failure evaluation (forensic engineering), design of metal structures, stability of rock masses, stability of dam structures, stability of bore holes, crack propagation in concrete, steel rebar/concrete matrix delamination, and failure mechanisms for cementitious materials.
An influence of nickel with heat treatment on the microstructure and fracture toughness of austempered ductile iron
Published in Canadian Metallurgical Quarterly, 2023
Subramanya Raghavendra, J. V. Raghavendra, Manjunatha Kuntanahalli Narayanappa, Chandra Shekar Anjinappa, K. G. Srinivas, B. Manjunatha
The energy release rate (G), crack opening displacement (COD), stress intensity factor (KI), and the J-Integral are all used in the fracture mechanics method. The overarching goal of fracture mechanics is to focus on the behaviour of materials in the presence of a crack. It laid the path for present engineering design.
Nonlinear dynamic and bilinear fatigue reliability analyses of marine risers in deep offshore fields
Published in Ships and Offshore Structures, 2018
Miner–Palmgren damage model defines the time to fatigue failure as time required for crack initiation in a material. However, for many design applications time of damage initiation is a very small percentage of the total life of the structure. Much of the time is spent in sub critical crack growth. Fracture mechanics deals with the ability of a material to resist crack propagation under a given set of loading and environmental conditions. With the aid of fracture mechanics, components can be designed to ensure that cracks do not reach a critical length during the design life of the structure (Paris & Erdogan 1963). Welds in risers/pipelines are normally made with a symmetric weld groove with welding from the outside only. The fatigue cracks always initiated at the toe of the weld root, in most cases from outer surface and propagated through the pipe wall thickness. The fatigue reliability and updating formulation used is based on a fracture mechanics approach given by the Paris crack propagation law (Madsen et al. 1986; Moan et al. 1993; Lotsberg & Sigurdsson 2005; Shi et al. 2014). In general, the Paris law may be used in a multi segmented crack growth (Figure 1) as follows: where a is the crack depth, N is the number of cycles, Ai is the crack growth rate parameter for segment i and m is its corresponding slope, ΔKth is the threshold of the stress intensity factor range and ΔKi is the point of intersection of two consecutive segments. In the present study bilinear elastic fracture mechanics has been adopted for limit state function as recommended by (BS7910 2005) for the fatigue assessment of welded structures, it is based on the study carried out by King et al. (1996). King performed a comprehensive collection of data from different sources and recommends a two segment crack growth law for steels. The uncertainties reported for both the segments are different, with the largest variability in the near threshold segment due to inherent uncertainty in ΔK, threshold below which no growth is experienced. On the other hand lower uncertainty of the upper segment corresponds to the crack growth rates behaviour well inside the stable region with higher values of ΔK. The two segments of the crack growth law are assumed as uncorrelated.