Adhesion Failure in Bonded Rubber Cylinders Part 1: Internal Penny-Shaped Cracks

2003 ◽  
Vol 76 (1) ◽  
pp. 160-173 ◽  
Author(s):  
D. C. Leicht ◽  
O. H. Yeoh ◽  
A. N. Gent ◽  
J. Padovan ◽  
R. L. Mullen
Keyword(s):  
Crack Length ◽  
Strain Energy Release ◽  
Element Analysis ◽  
Shape Factors ◽  
Metal Plates ◽  
Adhesion Failure ◽  
Penny Shaped Crack ◽  
Shaped Crack ◽  
Small Cracks ◽  
Tearing Energy

Abstract Rubber disks bonded between flat parallel metal plates are often used as adhesion test specimens such as ASTMD 429 1999, Method A. However, the mechanics of adhesion failure (debonding) for this geometry have not been fully analyzed previously. Therefore, a study has been conducted of the strain energy release rate (tearing energy) for bonded rubber disks having cracks at the rubber-to-metal bond. In this paper, we consider internal penny-shaped cracks. A future paper will discuss external ring cracks. 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 internal penny shaped crack located at the center of either one or both rubber-to-metal bonds. The rubber was assumed to be linearly elastic and nearly incompressible. For any bonded disk held in constant tension, the tearing energy was found to be a non-linear function of crack length. For small cracks, the tearing energy was linearly related to the crack length. As the crack grew, the tearing energy increased until it passed through a maximum value. The peak tearing energy was found to depend on the height of the disk. Finally, for large cracks, the tearing energy decreased as the crack grew. Analytical and empirical models were developed and shown to be in good agreement for both small and large cracks in disks of different dimensions.

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.

FATIGUE PROPERTIES OF A T TYPE WELDED JOINT IN A SMALL-SIZED SINGLE PASS BOILER HEADER

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3836-3841
Author(s):  
H. YAMAKAWA ◽  
R. MURAKAMI ◽  
D. YONEKURA ◽  
S. H. LEE ◽  
N. YAN
Keyword(s):  
Crack Length ◽  
Elastic Stress ◽  
Welded Joint ◽  
Fatigue Testing ◽  
Fatigue Properties ◽  
Strain Gauges ◽  
Element Analysis ◽  
Fatigue Specimen ◽  
Single Pass ◽  
Small Cracks

The design of small-sized single pass boilers is usually based on the construction code for small-sized boilers, in Japan. Design methods in this construction code and other country codes have not been clearly defined, although most of small-sized boiler's headers are constructed from two concentric circular shells and cover plates. Therefore, Finite Element Analysis (FEA) with a PC and measurement by strain gauges are mainly used in strength design of these boilers. In this study, a T type welded joint of SS400 was adopted for the header of small-sized single pass boilers. Fatigue testing and FEA was carried out. The fatigue limit was greater for base metal than for weldment. For the weldment, the S - N curve decreased with decreasing ρ value. The stress concentration at the toe was evaluated by the FEA. S - N curves for different toe curvature radii were re-drawn using maximum elastic stress, Ktσmax. Crack initiation occurred in the vicinity of the toe. Several small cracks were observed on the surface of T type welded joint fatigue specimen at N/N f =0.42. These cracks coalesced together at a crack length of 10mm. Fatigue crack growth rate lineally increased with increasing (crack length)1/2.

An Axisymmetric Crack in Bonded Materials With a Nonhomogeneous Interfacial Zone Under Torsion

1995 ◽  
Vol 62 (1) ◽  
pp. 116-125 ◽  
Author(s):  
M. Ozturk ◽  
F. Erdogan
Keyword(s):  
Crack Opening ◽  
Crack Problem ◽  
Strain Energy Release ◽  
Interfacial Region ◽  
Interfacial Zone ◽  
Mode Iii ◽  
Shear Moduli ◽  
Penny Shaped Crack ◽  
Energy Release Rates ◽  
Shaped Crack

In this study the mode III axisymmetric crack problem for two dissimilar homogeneous materials bonded through a thin layer of nonhomogeneous interfacial region is considered. The shear modulus of the interfacial layer is assumed to be μ2(z) = μ1 exp (αz). It is also assumed that μ3 = μ1 exp (αh), h being the thickness of the layer and μ1 and μ3 the shear moduli of the adherents. The main results of the study are the stress intensity factors, the strain energy release rates and, to a limited extent, the crack-opening displacements obtained as functions of the two primary variables h/a and μ3/μ1 under various loading conditions, where a is the radius of the crack. Some results are also presented for a penny-shaped crack in an unbounded nonhomogeneous medium.

Three-dimensional adhesion failure analysis of the single lap joint having pre-embedded circular defects

2019 ◽  
Vol 54 (5-6) ◽  
pp. 293-309 ◽  
Author(s):  
Ranjan K Behera ◽  
SK Parida ◽  
RR Das
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Release ◽  
Strain Energy ◽  
Strain Energy Release ◽  
Lap Joint ◽  
Element Analysis ◽  
Single Lap Joint ◽  
Adhesion Failure ◽  
The Finite Element Analysis

The present research aims to study the growth of the circular adhesion failure pre-existing at the interfaces of the strap adherend and the adhesive in a single lap joint. Three-dimensional nonlinear finite element analysis of adhesively bonded single lap joints made with high strength steel adherends under uniformly applied extension have been carried out. The interfacial stresses and strain energy release rate values, being indicative parameters, in the growth of the adhesion failures are computed in the vicinity of the pre-existing circular adhesion failure fronts when the load on single lap joint increases till failure. The magnitudes of the strain energy release rate are computed using the virtual crack closure technique. The results show that the sizes of the adhesion failure significantly influence the magnitudes of the interfacial stresses, the three modes of strain energy release rates and the load-bearing capacity of the single lap joint. The finite element analysis predicts that pre-embedded circular adhesion failures will not have grown from the pre-embedded circular adhesion failure front, instead the failure will be initiated from the overlap ends upon loading for the adhesive bonded single lap joint made with strong adherends and AV119 adhesive. The finite element analysis also proposes a method to calculate the strength of this type of joint configurations using the global shear strength of the adhesive and the intact bonded area. The finite element analysis predicted failure strength of the single lap joint is in good agreement with the experimentally obtained strength for the single lap joint containing pre-existing circular adhesion failure.

Thermal Misfit and Thermal Fatigue Induced Damage in Brittle Composites

1994 ◽  
Vol 350 ◽  
Author(s):  
N. Sridhar ◽  
J. M. Rickman ◽  
D. J. Srolovitz
Keyword(s):  
Thermal Expansion ◽  
Crack Growth ◽  
Spherical Inclusion ◽  
Strain Energy Release ◽  
Misfit Strain ◽  
Crack Size ◽  
Critical Crack ◽  
Penny Shaped Crack ◽  
The Matrix ◽  
Shaped Crack

AbstractWe examine the conditions under which differences in thermal expansion between a particle and the matrix leads to crack growth within the matrix. Using linear elastic fracture mechanics, we obtain closed-form, analytical results for the case of a penny shaped crack present in the matrix interacting with a spherical inclusion which is misfitting with respect to the matrix. A simple and direct relationship is established between the strain energy release rate, the crack size, the crack orientation with respect to the inclusion, the crack/inclusion separation, the degree of thermal expansion mismatch and the elastic properties of the medium. We also analyze the size to which these cracks can grow and find that for a given misfit strain and material properties, crack growth is inhibited beyond a certain critical crack size. Finally, the preferred orientation of these cracks as a function of misfit strain is predicted. The implication of these results for thermal cycling are analyzed.

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