Elastic-plastic fracture toughness of PC/ABS blend based on CTOD and J-integral methods

Polymer ◽  
1996 ◽  
Vol 37 (19) ◽  
pp. 4289-4297 ◽  
Author(s):  
Ming-Luen Lu ◽  
Kuo-Chan Chiou ◽  
Feng-Chih Chang
Keyword(s):  
Fracture Toughness ◽  
J Integral ◽  
Elastic Plastic ◽  
Integral Methods

Fracture Toughness of PVC/NBR Blends Evaluated by the J-Integral

1993 ◽  
Vol 66 (4) ◽  
pp. 634-645
Author(s):  
N. Nakajima ◽  
J. L. Liu
Keyword(s):  
Fracture Toughness ◽  
Energy Dissipation ◽  
Crack Initiation ◽  
Crack Tip ◽  
J Integral ◽  
Integral Methods ◽  
Locus Method ◽  
Two Phases ◽  
Fracture Processes

Abstract The effect of gel on the fracture toughness of four PVC/NBR (50/50) blends was characterized by two different J- integral methods. Three of these blends are compatible blends with 33% acrylonitrile in NBRs, and the fourth with 21% acrylonitrile content, is an incompatible blend. Two types of gel are involved in this study microgels and macrogels. The J-integral methods are (1) conventional method proposed by Bagley and Landes and (2) crack initiation locus method proposed by Kim and Joe. The same load-displacement curves are used in both methods. However, the latter eliminates the energy dissipation away from the crack tip in the determination of Jc, while the former does not. Both methods produced almost the same results indicating that the energy dissipation away from the crack tip is negligible in these samples. The fracture toughness of a macrogel-containing blend is much greater than that of a microgel-containing blend, which, in turn, is only slightly greater than that of a gel-free blend. This implies that the two gel-containing blends have different fracture processes. The incompatible blend has the lowest fracture toughness due to weak interaction at the boundaries of the two phases.

Experimental evaluation of fracture properties of bovine hip cortical bone using elastic–plastic fracture mechanics

2021 ◽  
pp. 1-10
Author(s):  
Waseem Ur Rahman ◽  
Rafiullah khan ◽  
Noor Rahman ◽  
Ziyad Awadh Alrowaili ◽  
Baseerat Bibi ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Plastic Deformation ◽  
Fracture Mechanics ◽  
Cortical Bone ◽  
Elastic Deformation ◽  
Compact Tension ◽  
J Integral ◽  
Elastic Plastic ◽  
American Society ◽  
Fracture Specimens

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.

An Experimental-Numerical Hybrid Method to Determine Dynamic Elastic-Plastic Fracture Toughness

2013 ◽  
Vol 577-578 ◽  
pp. 517-520 ◽  
Author(s):  
Shi Fan Zhu ◽  
Yang Cao ◽  
Chun Huan Guo ◽  
Feng Chun Jiang
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Dynamic Fracture ◽  
Dynamic Fracture Toughness ◽  
J Integral ◽  
Hopkinson Pressure Bar ◽  
Element Analysis ◽  
Three Point Bending ◽  
Elastic Plastic ◽  
Load Displacement

The dynamic fracture behavior of 7075-T6 aluminum alloy was studied by finite element method to simulate a cracked three-point bending specimen loaded by stress wave loading. In order to determine the elastic-plastic dynamic fracture toughness using quasi-static fracture mechanics theory, the nominal load measured by Hopkinson pressure bar loaded fracture testing system was input into a finite element program to calculate the loading point displacement, and then this displacement was employed to obtain the load-displacement field in the vicinity of the crack tip without the inertia effect, the variation of J-integral as a function of time was established using the load-displacement parameters determined by finite element analysis. The critical J-integral corresponding to crack initiation time detected by a small strain gauge mounted on the three-point bending fracture specimen is determined as an elastic-plastic dynamic fracture toughness (JId). The comparison between the equivalent dynamic fracture toughness(KId) given by the aforementioned procedures and the value measured in previous studies was made to verify the validation of the proposed procedure.

Fracture toughness of high-impact polystyrene based on three j-integral methods

1993 ◽  
Vol 47 (10) ◽  
pp. 1867-1880 ◽  
Author(s):  
Chang-Bing Lee ◽  
Ming-Luen Lu ◽  
Feng-Chih Chang
Keyword(s):  
Fracture Toughness ◽  
High Impact ◽  
J Integral ◽  
High Impact Polystyrene ◽  
Integral Methods

Influence of Weld Mismatch on the Structural Integrity of Pipes for Reeling

2008 ◽  
Author(s):  
Gustavo M. Castelluccio ◽  
Sebastian Cravero ◽  
Hugo A. Ernst
Keyword(s):  
Fracture Toughness ◽  
Structural Integrity ◽  
J Integral ◽  
Finite Element Analyses ◽  
Single Edge ◽  
Inhomogeneous Materials ◽  
Elastic Plastic ◽  
Edge Notch ◽  
Integrity Analysis ◽  
Crack Position

Structural integrity analysis of tough materials based on Elastic-Plastic Fracture Mechanics (EPFM) has been successfully employed in the assessment of components. EPFM has originally been developed for homogeneous materials and its applicability to inhomogeneous materials has some peculiarities. In particular, Fitness for Service design of welded pipes requires to know the weld fracture toughness and to estimate accurately the J-integral applied on the actual structural member. In this work, finite element analyses of simulated welds have been carried out in order to qualify and quantify the lack of accuracy of experimental methodologies for measuring fracture toughness of welds and the influence of welds on the applied J-integral in a pipe under bending. Different weld widths and cracks positions are characterized for single edge notch specimens in tension (SE(T)) and pipes. It has been found that inhomogeneity affects elastic-plastic fracture parameters for cracks centered in welds of certain widths. Moreover, the applied J-integral on pipes with circumferential cracks depends significantly on the weld width and crack position.

Comparison of J-Integral Values and J-R Curves Between Carbon Steel Compact Tension Specimen and Pipe Specimen

2004 ◽  
Author(s):  
Masahiro Takanashi ◽  
Satoshi Izumi ◽  
Shinsuke Sakai ◽  
Naoki Miura
Keyword(s):  
Fracture Toughness ◽  
Carbon Steel ◽  
Crack Initiation ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Small Scale ◽  
Outer Diameter ◽  
J Integral ◽  
Tension Specimen ◽  
Elastic Plastic

In the present study, the transferability of elastic-plastic fracture toughness from a small-scale to a large-scale specimen was experimentally confirmed for carbon steel pipe with mild toughness. Fracture toughness tests were carried out on a pipe specimen 318.5 mm in outer diameter, 10.3 mm in thickness and having a through-wall crack, and also on a compact tension specimen 9.7mm in thickness, 25.4 mm in width, that had been cut out from the pipe specimen. Test results indicated the J-integral value of the pipe specimen at the crack initiation to be nearly twice that of the CT specimen. Finite element analysis conducted on the two specimens indicated this difference to arise primarily from the constraint near the crack front. Discussion was also made of the effects of crack orientation on elastic-plastic fracture toughness of CT specimens. The J-integral value at crack initiation in the specimen whose crack direction coincided with the pipe axial was found to be almost 54 % more than for specimens whose crack direction was circumferential.

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