Fatigue Behavior and Damage Assessment of Stainless Steel/Aluminum Composites

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Volkan Eskizeybek ◽  
Ahmet Avci ◽  
Ahmet Akdemir ◽  
Ömer Sinan Şahin
Keyword(s):  
Stainless Steel ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Fracture Mechanics ◽  
Crack Growth ◽  
Fatigue Behavior ◽  
Laminated Composite ◽  
Strain Energy Release ◽  
Fatigue Loading ◽  
304 Stainless Steel

Fatigue crack growth and related damage mechanisms were investigated experimentally in a stainless steel/aluminum laminated composite with middle through thickness crack, and two different fracture mechanics approaches applied to the composite to reveal their differences under fatigue loading. The laminated composite material, which has a unidirectional continuous AISI 304 stainless steel as fibers and Al 1060 as matrix, was produced by using diffusion bonding. Fatigue tests were conducted in accordance with ASTM E 647. The relationships between fatigue crack growth rate (da/dN), stress intensity factor (ΔK), and strain energy release rate (ΔG) were determined; and damage behavior was discussed. Both linear elastic fracture mechanics (LEFM) and compliance method were used, and the results were compared with each other. It is found that as the crack propagates, the LEFM overestimates the ΔG values. Interlaminar and fiber/matrix interface damage were evaluated by fractographic examination.

Fatigue Behavior of Notched Aluminum Plates Repaired by Smart and Composite Patches

2010 ◽  
Author(s):  
S. Mohammad Reza Khalili ◽  
Reza Eslami Farsani ◽  
Pasha Mojahedi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Behavior ◽  
Laminated Composite ◽  
Fatigue Loading ◽  
Experimental Results ◽  
Crack Growth Behavior ◽  
Mode I ◽  
Aluminum Plates

In this study, mode I fatigue crack growth behavior of single edge notched thin aluminum plates repaired with single side composite patches is investigated experimentally. Three patches are investigated in this analysis, 1- three layers carbon/epoxy laminated composite patch, 2- smart patches contained shape memory alloy (SMA) wires without pre-strain embedded in between the carbon/epoxy layers, and 3- smart patches contained SMA wires with pre-strain embedded in between the carbon/epoxy layers. The results are compared with the results obtained for un-repaired notched plate and the influence of SMA wires is also studied. The experimental results show a significant increase in crack growth life in all repaired plates compared with un-repaired plate. The repaired plates with smart pre-strained SMA patches show greater life as compared to other plates repaired by other patches. The three layers carbon/epoxy patches show better results compared to smart SMA un-strained patches. Also, numerical modeling is done by ANSYS software to obtain the stress intensity factor in mode I fatigue loading and then applied to Paris law for prediction of the fatigue crack growth life. The results are compared with the experimental results and a good agreement is obtained.

Fatigue Life Prediction Based on Probabilistic Fracture Mechanics: Case Study of Automotive Parts

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Mahboubeh Yazdanipour ◽  
Mohammad Pourgol-Mohammad ◽  
Naghd-Ali Choupani ◽  
Mojtaba Yazdani
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Fracture Mechanics ◽  
Crack Growth ◽  
Probabilistic Models ◽  
Fatigue Loading ◽  
Critical Fields ◽  
Propagation Of Uncertainty ◽  
Automotive Parts ◽  
Crack Growth Model

This paper studies the stochastic behavior of fatigue crack growth analytically and empirically by employing basic models in fracture mechanics. The research estimates the crack growth rate probabilistically, quantifies the uncertainty of probabilistic models under fatigue loading in automotive parts, and applies the simulations on W319 aluminum alloy, which has vast applications in automotive components’ products. Walker and Forman correlations are used in the paper. The deterministic simulations of these models are verified with afgrow code and validated experimentally with fatigue data of W319 aluminum. Then, the models are treated probabilistically by considering the models’ parameters stochastic. Monte Carlo (MC) simulation is employed to investigate the models under stochastic conditions. The paper is quantifies the propagation of uncertainty with calculating the standard deviations of crack lengths via cycles. The proposed procedure is useful for selecting a proper probabilistic fatigue crack growth model in specific applications and can be used in future fatigue studies not only in the automotive industry but also in other critical fields, to obtain more reliable conclusions.

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