Fracture Behavior of Cracked Ring Specimen at Different Crack Positions

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Abdulmohsen M. Alqahtani ◽  
Thamer K. Albulayhid ◽  
Mutlaq N. Alotaibi ◽  
Ibrahim M. Alarifi ◽  
Tarek M. A. A. EL-Bagory
Keyword(s):  
Experimental Study ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Fracture Behavior ◽  
Radial Crack ◽  
Tensile Load ◽  
Plastic Pipe ◽  
Piping Systems ◽  
Crack Position

Abstract The previous research review of piping systems revealed that the plastic pipe companies suffered from many problems in natural gas pipeline systems. One of the most significant problems that appeared in the piping systems are external cracks due to manufacturing processes, welding technique, and installation processes. The principal goal of the present experimental study is to predict the crack growth behavior and energy release rate of cracked ring specimens made from high-density polyethylene (HDPE) under different crack position angles and various crosshead speeds. The effect of loading rate on the external radial crack at different crack position angles plays an important role in the prediction of fracture behavior of plastic pipe materials. For this reason, it is necessary to conduct a study for the fracture analysis of pipe ring specimens under tension loading with double external cracks at constant radial crack length to width ratio equal a/W = 0.5. A precracking machine is designed especially in the present experimental study to simulate the actual radial cracks at outer surface of pipe ring specimens. The effects of crosshead speed and crack position angle revealed a significant effect on the energy release rate and maximum applied load under tensile load.

Fracture Behavior of Cracked Ring Specimen at Different Crack Positions

2019 ◽  
Author(s):  
Abdulmohsen M. Alqahtani ◽  
Thamer K. Albulayhid ◽  
Mutlaq N. Alotaibi ◽  
Ibrahim M. Alarifi ◽  
Tarek M. A. A. El-Bagory
Keyword(s):  
Experimental Study ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Fracture Behavior ◽  
Radial Crack ◽  
Tensile Load ◽  
Ring Specimen ◽  
Piping Systems ◽  
Crack Position

Abstract The previous research review of piping systems revealed that the plastic pipes companies suffered from many problems in natural gas pipeline systems. One of the most significant problems appeared in the piping systems are external cracks due to manufacturing processes, welding technique and installation processes. The principal goal of the present experimental study is to predict the crack growth behavior and energy release rate of cracked ring specimen made from high-density polyethylene (HDPE) under different crack position angles and various crosshead speeds. The effect of loading rate on the external radial crack at different crack position angles plays an important role in the prediction of fracture behavior of plastic pipe materials. For this reasons, it is necessary to conduct a study for the fracture analysis of pipe ring specimen under tension loading with double external cracks at constant radial crack length to width ratio equal a/W = 0.5. Pre-cracking machine is designed especially in the present experimental study to simulate the actual radial cracks at outer surface of pipe ring specimens. The effects of crosshead speed and crack position angle are revealed a significant effect on the energy release rate and maximum applied load under tensile load.

Test Study of Fracture Mechanical Properties of Reactive Powder Concrete with Additives

2014 ◽  
Vol 904 ◽  
pp. 3-6 ◽  
Author(s):  
Zhi Gang Yin
Keyword(s):  
Mechanical Properties ◽  
Energy Release Rate ◽  
Fracture Energy ◽  
Energy Release ◽  
Release Rate ◽  
Fracture Behavior ◽  
Fracture Model ◽  
Reactive Powder Concrete ◽  
Critical Crack Length ◽  
Reactive Powder

The different influencing regular of fly-ash fractiontype of fibre (steel fibre and polypropylene fibre) and fibre fraction on the mechanical property and fracture behavior of Reactive Powder Concrete (PRC) are studied. Fracture mechanical properties of RPC is researched in double-K fracture model and fracture energy release rate G . Test results show that the crack propagation of RPC with steel fibers is limited. Its fracture toughness and pre-critical crack length is largely enhanced. Double-K fracture model and fracture energy release rate G are consistent with describing the fracture behavior of RPC.

scholarly journals Mode II fracture behavior of parallel strand bamboo measured by 3-point end-notched flexure tests

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 3219-3227
Author(s):  
Zhen-wen Zhang ◽  
Jia-liang Zhang ◽  
Yu-shun Li ◽  
Riu Liu
Keyword(s):  
Crack Propagation ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Fracture Process ◽  
Fracture Behavior ◽  
Critical Energy ◽  
Mode Ii ◽  
Critical Energy Release Rate ◽  
Propagation Length

Parallel strand bamboo (PSB) is a new type of bio-composite. In the present study, three-point bend end-notched flexure (3ENF) tests of PSB were conducted to analyze the fracture behavior including fracture process, resistant curves, and critical energy release rate in the longitudinal (L) system. The results show that transverse-longitudinal (TL) and thickness-longitudinal (ZL) specimens had the same fracture process including the stages of fracture process zone (FPZ) development and opening crack propagation but different mode II critical energy release rate (GIIc), and they indicate that the fiber bridging had a significant influence. The fracture processes suggest the PSB specimens of which the initial crack length was 0.5 times the half span had a stable crack propagating process, and the crack propagation length was wide enough to evaluate GIIc, which was 5.02 N∙mm-1 of TL specimens and 2.71 N∙mm-1 of ZL specimens. Besides, there was no obvious influence of span/depth ratio on the fracture resistance of both ZL and TL specimens when the ratio was larger than 15.

scholarly journals Analyses of delaminations in non-linear elastic multilayered inhomogeneous beam configurations

2020 ◽  
Vol 40 (3) ◽  
pp. 65-77
Author(s):  
Victor Rizov
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Cross Section ◽  
Release Rate ◽  
Strain Energy ◽  
Fracture Behavior ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Linear Elastic ◽  
Delamination Fracture

This paper presents investigation of delamination fracture behavior of multilayered non-linear elastic beam configurations by using the Ramberg-Osgood stress-strain relation. It is assumed that each layer exhibits continuous material inhomogeneity along the width as well as along thickness of the layer. An approach for determination of the strain energy release rate is developed for a delamination crack located arbitrary along the multilayered beam height. The approach can be applied for multilayered beams of arbitrary cross-section under combination of axial force and bending moments. The layers may have different thickness and material properties. The number of layers is arbitrary. The approach is applied for analyzing the delamination fracture behavior of a multilayered beam configuration subjected to four-point bending. The beam has a rectangular cross-section. The delamination crack is located symmetrically with respect to the beam midspan. The strain energy release rate is derived assuming that the modulus of elasticity varies continuously in the cross-section of each layer according to a hyperbolic law. In order to verify the solution to the strain energy release rate, the delamination fracture behavior of the multilayered non-linear elastic four-point bending beam configuration is studied also by applying the method of the J-integral. The solution to the strain energy release rate derived in the present paper is used in order to perform a parametric study of delamination.

An Experimental Study of Upper Hot Layer Stratification in Full-Scale Multiroom Fire Scenarios

1982 ◽  
Vol 104 (4) ◽  
pp. 741-749 ◽  
Author(s):  
L. Y. Cooper ◽  
M. Harkleroad ◽  
J. Quintiere ◽  
W. Rinkinen
Keyword(s):  
Experimental Study ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Simulation Models ◽  
Full Scale ◽  
Major Objective ◽  
Vertical Arrays ◽  
Fire Scenarios ◽  
Smoke Filling

This paper describes an experimental study of the dynamics of smoke filling in realistic, full-scale, multiroom fire scenarios. A major objective of the study was to generate an experimental data base for use in the verification of mathematical fire simulation models. The test space involved 2 or 3 rooms, connected by open doorways. During the course of the study the areas were partitioned to yield four different configurations. One of the rooms was a burn room containing a methane burner which produced either a constant energy release rate of 25, 100, or 225 kW or a time-varying energy release rate which increased linearly with time from zero at ignition to 300 kW in 10 min. An artificial smoke source near the ceiling of the burn room provided a means for visualizing the descent of the hot layer and the dynamics of the smoke filling process in the various spaces. The development of the hot stratified layers in the various spaces was monitored by vertical arrays of thermocouples and photometers. A layer interface was identified and its position as a function of time was determined. An analysis and discussion of these results are presented.

Calculating Energy Release Rate as a Function of Crack Length Using a Multiple-Step Crack Closure Technique in Tire Finite Element Models

2018 ◽  
Vol 46 (3) ◽  
pp. 130-152
Author(s):  
Dennis S. Kelliher
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Crack Length ◽  
Energy Release ◽  
Crack Closure ◽  
Release Rate ◽  
Fatigue Behavior ◽  
Three Dimensions ◽  
Quantitative Prediction ◽  
Closure Technique

ABSTRACT When performing predictive durability analyses on tires using finite element methods, it is generally recognized that energy release rate (ERR) is the best measure by which to characterize the fatigue behavior of rubber. By addressing actual cracks in a simulation geometry, ERR provides a more appropriate durability criterion than the strain energy density (SED) of geometries without cracks. If determined as a function of crack length and loading history, and augmented with material crack growth properties, ERR allows for a quantitative prediction of fatigue life. Complications arise, however, from extra steps required to implement the calculation of ERR within the analysis process. This article presents an overview and some details of a method to perform such analyses. The method involves a preprocessing step that automates the creation of a ribbon crack within an axisymmetric-geometry finite element model at a predetermined location. After inflating and expanding to three dimensions to fully load the tire against a surface, full ribbon sections of the crack are then incrementally closed through multiple solution steps, finally achieving complete closure. A postprocessing step is developed to determine ERR as a function of crack length from this enforced crack closure technique. This includes an innovative approach to calculating ERR as the crack length approaches zero.

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