Static and fatigue crack growth of epoxy adhesives and fractal dimensions

The characteristics of mechanical behavior are investigated for Ti-6Al-4V alloy. Four kinds of specimens are prepared under different heat treatments in order to produce different microstructures. In the present investigations, impact, tensile and fatigue crack growth tests are performed for each test specimen. The results obtained through the investigations are compared. Additionally, fractal dimensions of crack path are obtained using the box counting method. The results are: 1) the microstructures show as equiaxed, bimodal and lamellar microstructures respectively, 2) the impact energy and elongation are superior for the bimodal microstructure, and the hardness and tensile strength are superior for the lamellar microstructure, 3) the fatigue crack growth rate is similar for all microstructures in the low ΔK region while that of equiaxed microstructure is the largest, and that of lamellar microstructure is the lowest in the high ΔK region respectively, 4) the fractal dimension, D of lamellar microstructure shows higher value than that of the equiaxed and bimodal microstructures under 200 magnification view of the SEM micrographs.

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A discrete dislocation analysis of fatigue crack growth

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:2001509 ◽

2001 ◽

Vol 11 (PR5) ◽

pp. Pr5-69-Pr5-75

Author(s):

V. S. Deshpande ◽

H. H.M. Cleveringa ◽

E. Van der Giessen ◽

A. Needleman

Keyword(s):

Fatigue Crack ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Discrete Dislocation

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Fatigue Investigation of Elastomeric Structures

Tire Science and Technology ◽

10.2346/1.3481658 ◽

2010 ◽

Vol 38 (3) ◽

pp. 194-212 ◽

Cited By ~ 11

Author(s):

Bastian Näser ◽

Michael Kaliske ◽

Will V. Mars

Keyword(s):

Fatigue Crack ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Material Behavior ◽

Period Effect ◽

Numerical Representation ◽

Material Force ◽

Strain Behavior ◽

Dissipative Effects ◽

Elastomeric Materials

Abstract Fatigue crack growth can occur in elastomeric structures whenever cyclic loading is applied. In order to design robust products, sensitivity to fatigue crack growth must be investigated and minimized. The task has two basic components: (1) to define the material behavior through measurements showing how the crack growth rate depends on conditions that drive the crack, and (2) to compute the conditions experienced by the crack. Important features relevant to the analysis of structures include time-dependent aspects of rubber’s stress-strain behavior (as recently demonstrated via the dwell period effect observed by Harbour et al.), and strain induced crystallization. For the numerical representation, classical fracture mechanical concepts are reviewed and the novel material force approach is introduced. With the material force approach at hand, even dissipative effects of elastomeric materials can be investigated. These complex properties of fatigue crack behavior are illustrated in the context of tire durability simulations as an important field of application.

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