scholarly journals Characteristic Tearing Energy and Fatigue Crack Propagation of Filled Natural Rubber

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3891
Author(s):  
Jigang Rong ◽  
Jun Yang ◽  
Youjian Huang ◽  
Wenbo Luo ◽  
Xiaoling Hu
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Pure Shear ◽  
Fatigue Loading ◽  
Propagation Length ◽  
Cutting Method ◽  
Tearing Energy ◽  
Propagation Experiment ◽  
Crack Propagation Experiment

Below the incipient characteristic tearing energy (T0), cracks will not grow in rubber under fatigue loading. Hence, determination of the characteristic tearing energy T0 is very important in the rubber industry. A rubber cutting experiment was conducted to determine the T0, using the cutting method proposed originally by Lake and Yeoh. Then, a fatigue crack propagation experiment on a edge-notched pure shear specimen under variable amplitude loading was studied. A method to obtain the crack propagation rate da/dN from the relationship of the crack propagation length (Δa) with the number of cycles (N) is proposed. Finally, the T0 obtained from the cutting method is compared with the value decided by the fatigue crack propagation experiment. The values of T0 obtained from the two different methods are a little different.

Fatigue Crack Modeling and Simulation Based on Continuum Damage Mechanics

2006 ◽  
Vol 129 (1) ◽  
pp. 96-102 ◽  
Author(s):  
Masakazu Takagaki ◽  
Toshiya Nakamura
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Continuum Damage Mechanics ◽  
Fatigue Loading ◽  
Present Theory ◽  
Continuum Damage ◽  
Cycle Fatigue

Numerical simulation of fatigue crack propagation based on fracture mechanics and the conventional finite element method requires a huge amount of computational resources when the cracked structure shows a complicated condition such as the multiple site damage or thermal fatigue. The objective of the present study is to develop a simulation technique for fatigue crack propagation that can be applied to complex situations by employing the continuum damage mechanics (CDM). An anisotropic damage tensor is defined to model a macroscopic fatigue crack. The validity of the present theory is examined by comparing the elastic stress distributions around the crack tip with those obtained by a conventional method. Combined with a nonlinear elasto-plastic constitutive equation, numerical simulations are conducted for low cycle fatigue crack propagation in a plate with one or two cracks. The results show good agreement with the experiments. Finally, propagations of multiply distributed cracks under low cycle fatigue loading are simulated to demonstrate the potential application of the present method.

Adhesion Failure in Bonded Rubber Cylinders Part 2: Fatigue Life Prediction of External Ring-Shaped Cracks Using Tearing Energy Approach

2003 ◽  
Vol 76 (2) ◽  
pp. 365-385 ◽  
Author(s):  
Douglas C. Leicht ◽  
C. Rimnac ◽  
R. Mullen
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Propagation ◽  
Crack Length ◽  
Fatigue Crack Propagation ◽  
Shape Factors ◽  
External Ring ◽  
Adhesion Failure ◽  
Shaped Crack ◽  
Tearing Energy

Abstract Rubber disks bonded between flat parallel metal plates are often used as adhesion test specimens; for example, ASTM D 429 1999, Method A. However, the mechanics of adhesion failure (debonding) for this geometry have not previously been fully analyzed. Therefore, a study was conducted to determine the strain energy release rate (tearing energy) for bonded rubber disks having external ring cracks at the rubber-to-metal bond and to develop a method for predicting the fatigue life. Finite element analysis was used to determine the tearing energy as a function of crack length for disks of various dimensions (shape factors). The crack configurations considered were an external-ring-shaped crack located at the outside circumference of either one or both rubber-to-metal bonds. The fatigue crack propagation (FCP) behavior was characterized for a generic filled natural rubber material. The tearing energy was found to be a non-linear function of crack length. For small cracks, the tearing energy was small and approached zero as the crack length decreased. The tearing energy then increased as the crack grew, indicating accelerating growth, until it passed through a maximum value. The peak tearing energy was found to depend on the height of the disk. Finally at large cracks, the tearing energy decreased or was essentially constant as the crack grew. The fatigue life of the rubber cylinders at different shape factors was determined experimentally. An empirical model coupled with the fatigue crack propagation behavior (FCP) for the material at different tearing energies was used to predict the fatigue life. The experimental and predicted fatigue life showed excellent agreement at low and moderate shape factors. However at high shape factors, fatigue life was not well predicted. From the experimental results, it was found that, at high shape factors, cavitation occurs causing a series of “dimples” to form, which leads to the development of an internal penny-crack, thereby violating the assumed model of an external ring-shaped crack.

Transient Fatigue Crack-Growth Behavior and Damage Zones in Zr-Based Bulk Metallic Glass

2003 ◽  
Vol 806 ◽  
Author(s):  
Peter A. Hess ◽  
Reinhold H. Dauskardt
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Crack Closure ◽  
Growth Rates ◽  
Fatigue Loading ◽  
Structural Applications ◽  
Crack Growth Rates

ABSTRACTFatigue crack propagation mechanisms of bulk metallic glasses (BMGs) are not well understood, limiting their use in safety-critical structural applications particularly where complex fatigue loading may occur. Accordingly, the present study examines the effects of variable amplitude fatigue loading associated with block loading and tensile overloads on fatigue crack-growth rates in a Zr-based BMG. Crack growth studies were conducted on compact tension specimens using computer control of the applied stress intensity range, ΔK. Fatigue crack closure loads, which represent the initial contact of mating crack surfaces during the unloading cycle, were continuously monitored during testing. Abrupt drops in ΔK were found to significantly decrease fatigue crack-growth rates far below equilibrium values, arresting growth completely at a ΔK twice the nominal fatigue threshold ΔKTH. Conversely, an abrupt increase in ΔK was found to accelerate fatigue crack-growth rates. The effects of roughness-induced crack closure were assessed and found to be consistent with the suppression or acceleration of growth rates. However, in order to fully explain the observed transient growth rate response, other mechanisms that may be related to the fatigue mechanism itself were also considered. Specifically, the nature of the fatigue crack tip damage zone was also investigated. As BMGs lack distributed plasticity at low temperatures, the plastic zone differs greatly from that seen in ductile crystalline materials, and its role in fatigue crack propagation mechanisms is examined.

Method of Construction for High Cycle Fatigue Resistant Pressure Vessels in Hydrogen Service

2018 ◽  
Author(s):  
Pooya Mahmoudian
Keyword(s):  
Fatigue Crack ◽  
Fracture Mechanics ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Applied Pressure ◽  
Design Procedure ◽  
Fatigue Loading ◽  
Crack Size ◽  
Initial Crack ◽  
Pressure Vessels

Currently, pressure vessels that operate in hydrogen service and subjected to fatigue must be designed using a defect tolerant design procedure. This means that first the fracture mechanics properties of the material being considered must be measured in hydrogen at the maximum service pressure. The properties are fatigue crack propagation properties and threshold stress intensity factor for hydrogen embrittlement (KIHE). With these properties, a fatigue crack propagation life can be estimated assuming an initial crack size and geometry and growing this defect to failure. The property measurements are costly and can only be performed at a few laboratories. Furthermore, the resulting lives are usually very short because of the assumed initial crack size. These things limit the application of this design method to lower cycle or static loading applications. This work introduces a cost-effective method of design and construction of pressure vessels for high cycle use in hydrogen service at pressures below 40,000 psi that eliminates the need for determining fracture mechanics properties in hydrogen environment. The method uses shrink fit construction of a liner inside a jacket. The method requires that when the pressure is applied, the magnitude of the resultant stress at the pressure boundary of the liner is more compressive than the magnitude of the applied pressure and the maximum allowed size of defect in the jacket at the interface between the jacket and the liner is such that when the cyclic stress is applied the resultant fatigue loading of that defect at that location to be less than the threshold value for growth of that defect.

Fatigue Crack Growth Life Prediction of an Extruded Thick-Walled Cylinder With Internal Axial Crack

2009 ◽  
Author(s):  
M. A. Malik ◽  
I. Salam ◽  
W. Muhammad
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Experimental Work ◽  
Fatigue Loading ◽  
Axial Crack ◽  
Fatigue Crack Growth Life ◽  
Walled Cylinder

The integrity of nearly all engineering structures is threatened by the presence of cracks. Structural failure occurs if a crack larger than a critical size exists. Although most well designed structures initially contain no critical cracks, subcritical cracks can grow to failure under fatigue loading, called fatigue crack propagation. Fatigue failure, that is, failure under repeated or cyclic loading, is a serious concern of engineering design. Under fatigue loading, the component may fail at a stress level that is far below its yield strength. The extruded materials are extensively used in chemical, food and nuclear industry and generally offer a unique combination of strength and freedom with regard to design solutions. During extrusion, material flow occurs in the direction of applied force and as a result microstructure changes. The process ultimately induces variation in the mechanical properties when tested along or across the extrusion direction. In present study, the fatigue crack propagation in a thick-walled cylinder is analyzed through detailed experimental work and finite element analysis and the fatigue crack growth life of the cylinder, with internal axial crack, has been predicted. Fatigue crack growth tests were conducted on middle tension, M(T), samples. The fatigue crack growth data of the cylinder is obtained in the transverse direction which experiences the maximum tensile stress (hoop stress). The tests were conducted at ambient temperature in air atmosphere. The data thus obtained include the fatigue crack growth and the SN curves. The fatigue crack growth life of the thick-walled cylinder has been predicted with ANSYS structural software. An ANSYS Parametric Design Language (APDL) code has been written to simulate the crack growth process. The actual data obtained from the experimental work has been used for the simulation work.

Fatigue crack propagation under biaxial fatigue loading with single overloads

2018 ◽  
Vol 109 ◽  
pp. 103-113 ◽  
Author(s):  
Siddhant Datta ◽  
Aditi Chattopadhyay ◽  
Nagaraja Iyyer ◽  
Nam Phan
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Fatigue Loading ◽  
Biaxial Fatigue

scholarly journals Analysis of biaxial proportional low-cycle fatigue crack propagation for hull inclined-crack plate based on accumulative plasticity

2022 ◽  
Vol 4 (2) ◽  
Author(s):  
Junlin Deng ◽  
Wenling Tu ◽  
Qin Dong ◽  
Dawei Dong ◽  
Shenglin Qiu
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Low Cycle Fatigue ◽  
Strong Dependence ◽  
Fatigue Loading ◽  
Cycle Fatigue ◽  
Inclined Crack ◽  
Hull Structure ◽  
Stress Ratios

AbstractFracture failures of ship plates subjected to in-plane biaxial low-cycle fatigue loading are generally the coupling result of accumulative plasticity and biaxial low-cycle fatigue damage. A biaxial low-cycle fatigue crack growth analysis of hull structure that accounts for the accumulative plasticity effect can be more suitable for the actual evaluation of the overall fracture performance of the hull structure in severe sea conditions. An analytical model of biaxial low-cycle fatigue crack propagation with a control parameter for ∆CTOD is presented for hull inclined-crack plate. A test was conducted for cruciform specimens made of Q235 steel with an inclined crack to validate the presented analysis. The biaxial accumulative plasticity behavior and the effects of biaxiality and stress ratios were investigated. The results of this study reveal a strong dependence of biaxial low-cycle fatigue crack propagation on biaxial accumulated plasticity.

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