The load separation criterion in elastic-plastic fracture mechanics: Rate and temperature dependence of the material plastic deformation function in an ABS resin

2012 ◽  
Author(s):  
Silvia Agnelli ◽  
Francesco Baldi ◽  
Theonis Riccò
2021 ◽  
pp. 1-10
Author(s):  
Waseem Ur Rahman ◽  
Rafiullah khan ◽  
Noor Rahman ◽  
Ziyad Awadh Alrowaili ◽  
Baseerat Bibi ◽  
...  

BACKGROUND: Understanding the fracture mechanics of bone is very important in both the medical and bioengineering field. Bone is a hierarchical natural composite material of nanoscale collagen fibers and inorganic material. OBJECTIVE: This study investigates and presents the fracture toughness of bovine cortical bone by using elastic plastic fracture mechanics. METHODS: The J-integral was used as a parameter to calculate the energies utilized in both elastic deformation (Jel) and plastic deformation (Jpl) of the hipbone fracture. Twenty four different types of specimens, i.e. longitudinal compact tension (CT) specimens, transverse CT specimens, and also rectangular unnotched specimens for tension in longitudinal and transverse orientation, were cut from the bovine hip bone of the middle diaphysis. All CT specimens were prepared according to the American Society for Testing and Materials (ASTM) E1820 standard and were tested at room temperature. RESULTS: The results showed that the average total J-integral in transverse CT fracture specimens is 26% greater than that of longitudinal CT fracture specimens. For longitudinal-fractured and transverse-fractured cortical specimens, the energy used in the elastic deformation was found to be 2.8–3 times less than the energy used in the plastic deformation. CONCLUSION: The findings indicate that the overall fracture toughness measured using the J-integral is significantly higher than the toughness calculated by the stress intensity factor. Therefore, J-integral should be employ to compute the fracture toughness of cortical bone.


2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.


2018 ◽  
Vol 148 ◽  
pp. 177-187 ◽  
Author(s):  
Markus Alfreider ◽  
Darjan Kozic ◽  
Otmar Kolednik ◽  
Daniel Kiener

2021 ◽  
Vol 158 ◽  
pp. 103876
Author(s):  
Qi-lin Xiong ◽  
Zhenhuan Li ◽  
Takahiro Shimada ◽  
Takayuki Kitamura

2013 ◽  
Vol 687 ◽  
pp. 118-123 ◽  
Author(s):  
Oliver Weichold ◽  
Udo Antons

The effect of incorporating elastomeric domains in concrete is described from the point of fracture mechanics. Concrete is subject to brittle failure, since cracks propagate at an enormous speed in the crystalline matrix. However, micro cracks are attracted to volume elements with lower elastic moduli such as elastomeric domains. Cracks that encounter the concrete-elastomer interface are stopped since energy is dissipated by plastic deformation of and/or crack deflection by the elastomer. The domain size and the distribution of the elastomer as well as, and properties of the elastomer-concrete interface are crucial parameters. Such a combination differs substantially from previously prepared polymer-impregnated concretes, in which only glassy polymers were used.


Author(s):  
Adolfo Arrieta-Ruiz ◽  
Eric Meister ◽  
Stéphane Vidard

Structural integrity of the Reactor Pressure Vessel (RPV) is one of the main concerns regarding safety and lifetime of Nuclear Power Plants (NPP) since this component is considered as not reasonably replaceable. Fast fracture risk is the main potential damage considered in the integrity assessment of RPV. In France, deterministic integrity assessment for RPV vis-à-vis the brittle fracture risk is based on the crack initiation stage. As regards the core area in particular, the stability of an under-clad postulated flaw is currently evaluated under a Pressurized Thermal Shock (PTS) through a dedicated fracture mechanics simplified method called “beta method”. However, flaw stability analyses are also carried-out in several other areas of the RPV. Thence-forward performing uniform simplified inservice analyses of flaw stability is a major concern for EDF. In this context, 3D finite element elastic-plastic calculations with flaw modelling in the nozzle have been carried out recently and the corresponding results have been compared to those provided by the beta method, codified in the French RSE-M code for under-clad defects in the core area, in the most severe events. The purpose of this work is to validate the employment of the core area fracture mechanics simplified method as a conservative approach for the under-clad postulated flaw stability assessment in the complex geometry of the nozzle. This paper presents both simplified and 3D modelling flaw stability evaluation methods and the corresponding results obtained by running a PTS event. It shows that the employment of the “beta method” provides conservative results in comparison to those produced by elastic-plastic calculations for the cases here studied.


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