scholarly journals The J-integral fracture toughness of PP/CaCO3 composites

1994 ◽  
Vol 29 (14) ◽  
pp. 3754-3758 ◽  
Author(s):  
Li Dongming ◽  
Zheng Wenge ◽  
Qi Zongneng
Keyword(s):  
Fracture Toughness ◽  
J Integral

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.

J-integral Fracture Toughness of High-Mn Steels at Room and Cryogenic Temperatures

2019 ◽  
Vol 50 (6) ◽  
pp. 2678-2689 ◽  
Author(s):  
Junhyeok Park ◽  
Kwanho Lee ◽  
Hyokyung Sung ◽  
Yong Jin Kim ◽  
Sung Kyu Kim ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
J Integral ◽  
Cryogenic Temperatures

Experimental and numerical determination of mode II fracture toughness of woven composites verified through unidirectional composite test data

2019 ◽  
Vol 27 (9) ◽  
pp. 557-566
Author(s):  
Rowan Healey ◽  
Nabil M Chowdhury ◽  
Wing Kong Chiu ◽  
John Wang
Keyword(s):  
Fracture Toughness ◽  
Displacement Field ◽  
Experimental Testing ◽  
Three Dimensional ◽  
Experimental Results ◽  
Woven Composites ◽  
Mode Ii ◽  
Numerical Comparison ◽  
J Integral ◽  
Mode Ii Fracture Toughness

Due to the increase in prevalence of fibre-reinforced polymer matrix composites (FRPMC) in aircraft structures, the need for adaption of failure prediction tools such as fatigue spectra has become more pertinent. Fracture toughness is an important measure with regard to fatigue, while adequate techniques and an ASTM standard for unidirectional FRPMC exist, there are mixed opinions when investigating woven FRPMC. This study describes a three-dimensional finite element model developed to assist in determining the mode II interlaminar fracture toughness ( GIIc) of fibre-reinforced woven composites, validated by an experimental and numerical comparison of GIIc determination for unidirectional FRPMC. Experimental testing mirroring the ASTM D7905 resulted in a measure of 1176 J m−2for the unidirectional specimen, while comparisons made with the literature achieved an average value of 1459.24 J m−2or the woven specimen. Three numerical methods were employed due to their prominence in the literature: displacement field, virtual crack closure techniques and the J integral. Both the J integral and the displacement field three-dimensional models produced satisfactory unidirectional GIIc estimates of 1284 and 1116.8 J m−2, respectively. Displacement field had a 5% uncertainty in GIIc when compared with experimental results, while J integral had an approximately 8.5% uncertainty. Extending the analysis to the woven specimens, values of 1302.8 and 1465.3 J m−2were obtained from J integral and displacement field methods, respectively, both within 10% of the experimental values. Hence, numerically determined unidirectional GIIc values were verified with experimental results, leading to the successful employment and extension to woven composites which displayed similar agreement.

Fracture Mechanism and Fracture Toughness at the Interface Between Cortical and Cancellous Bone

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Pankaj Shitole ◽  
Arpan Gupta ◽  
Rajesh Ghosh
Keyword(s):  
Fracture Toughness ◽  
Cortical Bone ◽  
Cancellous Bone ◽  
Fracture Mechanism ◽  
Fracture Mechanisms ◽  
J Integral ◽  
Single Edge ◽  
Plastic Part ◽  
Edge Notch ◽  
Sample Width

The microstructure at the interface of cortical and cancellous bone is quite complicated. The fracture mechanisms at this location are necessary for understanding the comprehensive fracture of the whole bone. The goal of this study is to identify fracture toughness in terms of J integral and fracture mechanism at the interface between cortical and cancellous bone. For this purpose, single edge notch bend (SENB) specimens were prepared from bovine proximal femur according to ASTM-E399 standard. Bone samples were prepared such that half of the sample width consists of cortical bone and other half of the width was cancellous bone; this interfacial bone is referred as a corticellous bone. Elastic–plastic fracture mechanics was used to measure fracture toughness. The J integral (both elastic and plastic) was used to quantify the fracture toughness. The plastic part of J integral value (Jpl) of corticellous specimen was 9310 J m−2, and shown to be 27 times of the J integral of the elastic part (Jel), 341 J m−2. The total J integral of the corticellous bone was found to be 9651 J m−2, which is close to two times of the cortical bone, 4731 J m−2. This study observed that J integral of corticellous bone is higher than the cortical bone since more energy is required for plastic deformation of corticellous bone due to crack branches and slowdown at the interface between cortical and cancellous bone.

Determination of Material Fracture Toughness by Circular Pre-Cracked Small Punch Test Specimens

2019 ◽  
Vol 795 ◽  
pp. 165-171
Author(s):  
Wu Lin Wang ◽  
Du Wei Wang ◽  
Kai Shu Guan
Keyword(s):  
Fracture Toughness ◽  
Empirical Correlation ◽  
Fracture Toughness Test ◽  
J Integral ◽  
Small Punch Test ◽  
Small Punch ◽  
Punch Test ◽  
Determination Procedure ◽  
Material Fracture

Fracture toughness empirical correlation between SPT(Small Punch Test) with non-crack sample and standard fracture toughness test has been established in recent years. In order to compensate the imperfection of empirical correlation, such as absence theoretical basis, poor repeatability and universality, in this paper, an O-type pre-cracked sample was adopted to evaluate fracture toughness. The mechanical model of the sample is in compliance with plane strain condition in the direction of crack propagation. In this paper a determination procedure was studied and established, and the J-integral of steel Q345R was calculated using the procedure.

The J integral fracture toughness and damage zone morphology in polyethylenes

Polymer ◽  
1991 ◽  
Vol 32 (8) ◽  
pp. 1440-1446 ◽  
Author(s):  
H. Swei ◽  
B. Crist ◽  
S.H. Carr
Keyword(s):  
Fracture Toughness ◽  
Damage Zone ◽  
J Integral

Preparation and Properties of Nano-Calcium Carbonate Modified PVC Using Ultrasonic Irradiation

2007 ◽  
Author(s):  
Shengfei Hu ◽  
Wen Chen ◽  
Huaxing Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Polymer Nanocomposites ◽  
Ultrasonic Irradiation ◽  
Integral Method ◽  
J Integral ◽  
Optimum Time ◽  
Mechanical Performances ◽  
Dispersion Of Nanoparticles ◽  
Better Than

PVC/nano-CaCO3 composites were prepared through ultrasonic irradiation. The optimum time of ultrasonic irradiation is 30 min. The fracture toughness of the nanocomposites was investigated by J-integral method based on the mechanical properties and morphology. Compared with corresponding nanocomposites and unfilled PVC, the prepared nanocomposites exhibit outstanding mechanical performances. The mechanical properties of spindly shaped CaCO3 filled PVC are better than these of the cubic nano-CaCO3, which are likely attributed to high aspect ratio of spindly shaped nano-CaCO3. In addition, the mechanical properties of PVC/nano-CaCO3 composites can be improved considerably when the content of nano-CaCO3 is 5–15 phr. Ultrasonic irradiation realizes the excellent dispersion of nanoparticles in the PVC, and offers a new way to deal with the challenges encountered in preparing polymer/nanocomposites materials.

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