scholarly journals Fatigue Damage of Al/SiC Composites - Macroscopic and Microscopic Analysis

2015 ◽  
Vol 60 (1) ◽  
pp. 101-105 ◽  
Author(s):  
A. Rutecka ◽  
Z.L. Kowalewski ◽  
K. Makowska ◽  
K. Pietrzak ◽  
L. Dietrich
Keyword(s):  
Fatigue Damage ◽  
Microscopic Analysis ◽  
Inelastic Strain ◽  
Damage Parameter ◽  
Fatigue Tests ◽  
Cyclic Plasticity ◽  
Damage Mechanisms ◽  
Before And After ◽  
Fatigue Damage Parameter ◽  
Sic Composites

Abstract The results of comparative examinations of mechanical behaviour during fatigue loads and microstructure assessment before and after fatigue tests were presented. Composites of aluminium matrix and SiC reinforcement manufactured using the KoBo method were investigated. The combinations of two kinds of fatigue damage mechanisms were observed. The first one governed by cyclic plasticity and related to inelastic strain amplitude changes and the second one expressed in a form of ratcheting based on changes in mean inelastic strain. The higher SiC content the less influence of the fatigue damage mechanisms on material behaviour was observed. Attempts have been made to evaluate an appropriate fatigue damage parameter. However, it still needs further improvements.

Application of Advanced Fatigue Damage Parameters in Comparison With Fatigue Analysis Included in Codes and Standards

2014 ◽  
Author(s):  
Philipp Rettenmeier ◽  
Karl-Heinz Herter ◽  
Xaver Schuler ◽  
Thomas Markus Fesich
Keyword(s):  
Cyclic Loading ◽  
Fatigue Damage ◽  
Fatigue Loading ◽  
Fatigue Analysis ◽  
Damage Parameter ◽  
Fatigue Tests ◽  
Loading Conditions ◽  
Critical Plane ◽  
Fatigue Assessment ◽  
Fatigue Damage Parameter

Technical components are subjected to cyclic loading conditions that can be arbitrarily complex in the most general case. For analytical fatigue strength verifications in the finite life regime both the uniaxial material characteristics by means of Wöhler curves as well as a representative equivalent fatigue damage parameter (FDP) for multiaxial cyclic loadings have to be determined. For simple loading conditions, the fatigue assessment can be performed using well-known and verified strength hypotheses for quasi-static loading conditions. However, for complex non-proportional cyclic loading conditions with rotating principle stress directions the application of these hypotheses is not sufficiently verified. Hence, advanced stress, strain or energy based strength hypotheses in critical plane formulation are used. These hypotheses require considerable numerical efforts. The fatigue concept (MPA AIM-Life) enables an assessment of complex fatigue loading conditions with different advanced strength hypotheses. An interface to the finite element code ABAQUS allows the fatigue assessment of complex component geometries. Based on fatigue tests of specimens made from ferritic and austenitic materials under uniaxial and multiaxial loading conditions (tension/torsion) the accuracy of different strength hypotheses is demonstrated. Therefore the fatigue analysis assessment included in codes and standards is compared to different advanced fatigue damage parameters.

Thermomechanical Model and Experimental Analysis of Progressive Fatigue Damage in Steel Specimens

2006 ◽  
Author(s):  
Francesca Cura` ◽  
Graziano Curti ◽  
Raffaella Sesana
Keyword(s):  
Differential Equation ◽  
Fatigue Damage ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Steel Specimen ◽  
Damage Parameter ◽  
Fatigue Tests ◽  
Temperature Evolution ◽  
Thermomechanical Model ◽  
Temperature Growth

This paper presents a thermomechanical model to predict the surface temperature evolution of a specimen during a fatigue test. In particular, the aim of this theoretical approach is to evaluate the amount of accumulated fatigue damage in the material, on the basis of its temperature growth indicated as damage parameter. To do that, a thermomechanical model has been developed and applied to a unidimensional steel specimen, with rectangular cross-section, fatigued by alternate axial stresses. Temperature variation along the thickness of the specimen has been disregarded. Thermomechanical differential equation has been integrated by applying both initial and boundary conditions. Temperature evolution of steel specimens measured during fatigue tests by means of thermographic techniques has been compared to the corresponding predicted by the theoretical model.

scholarly journals The influence of a quay crane sea transportation on its further exploitation

Transport ◽  
2017 ◽  
Vol 33 (2) ◽  
pp. 536-542 ◽  
Author(s):  
Maksym Starykov ◽  
Frank Van Hoorn
Keyword(s):  
Fatigue Damage ◽  
Damage Parameter ◽  
The Other ◽  
Ship Motions ◽  
The Real ◽  
Container Cranes ◽  
Normal Operating ◽  
Sea Transportation ◽  
Time Savings ◽  
Fatigue Damage Parameter

For the last decades, fully erected container cranes have been delivered to a customer site by ships. On one hand, using this method of transportation is very attractive due to its cost and time savings. However, on the other hand, being exposed to cycling loads from the ship motions during the sea voyage, the crane structure accumulates fatigue damage. Using the accumulated fatigue damage parameter, the crane transportation could be associated with the amount of the working cycles the crane could have worked out during its normal operating at the customer site. In the presenting paper the research for the real case of a new crane voyage from China to Ukraine has been done.

Fatigue Behaviour of Lead-Free Solder Interconnections in Life Prediction of Trilayer Structures Subjected to Thermal Cycling

2015 ◽  
Author(s):  
Alireza Shirazi ◽  
Hua Lu ◽  
Ahmad Varvani-Farahani
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Life Prediction ◽  
Damage Parameter ◽  
Fatigue Life Prediction ◽  
Lead Free Solder ◽  
Critical Plane ◽  
Trilayer Structure ◽  
Fatigue Damage Parameter ◽  
Free Solder

Trilayer structures such as flip chip plastic ball grid array (FC-PBGA) packages are bodies made of a large variety of dissimilar materials. Due to the coefficients of thermal expansion (CTE) mismatches between and temperature gradients within the layers, thermally induced interaction becomes a typical type of the loads for the joint layer made of lead-free solder joint interconnections. Thermal stresses and strains at the interfaces of solder joints and neighboring adhesive layers are the cause for solder joint fatigue failures, which account for the most common package failures. The current study puts forward a fatigue life prediction method for a trilayer structure using the critical plane-energy fatigue damage parameter in combination with the modified Coffin-Manson life model. The proposed method of calculated fatigue damage parameter for the samples of study, along with their experimental life (Nf50%) under two different thermal conditions is presented. The values of life in (0–100°C) condition and (25–125°C) with the same temperature ramp rate and dwell conditions are found to differ by a factor of 1.3 where the structures tested under (0–100°C) condition show lower lives. The present study further correlated the fatigue damage parameters with the Coffin-Manson type equation to calculate/predict the fatigue life of structures under (25–125°C) condition. The results of the Nf50 fatigue life prediction versus the experimental cycles show that the predicted lives of samples with SAC305 solder joints fall apart with a factor ranging from (1.24)∼(−1.45). The advantage of the proposed method in comparison with the existing methods in life prediction of the trilayer structure with solder alloy is that there are no empirical parameters involved in energy-critical plane damage parameter in life prediction of the trilayer structure. Parameters within the proposed approach purely involves mechanical and fatigue properties of the midlayer alloy.

A Study on the Fatigue Life Prediction and Evaluation of the Natural Rubber Components for Automobile Vehicles

2006 ◽  
Vol 326-328 ◽  
pp. 589-592
Author(s):  
Chang Su Woo ◽  
Wan Doo Kim ◽  
Jae Do Kwon
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Natural Rubber ◽  
Fatigue Damage ◽  
Damage Parameter ◽  
Fatigue Tests ◽  
Element Analysis ◽  
Engine Mount ◽  
Lagrange Strain

The fatigue analysis and lifetime evaluation are very important in design procedure to assure the safety and reliability of the rubber components. The interest of the fatigue life of rubber components such as the engine mount is increasing according to the extension of warranty period of the automotive components. In this study, the fatigue lifetime prediction methodology of the vulcanized natural rubber was proposed by incorporating the finite element analysis and fatigue damage parameter determined from fatigue tests. Finite element analysis of 3D dumbbell specimen of natural rubber was performed based on a hyper-elastic material model determined from the tension, compression and shear tests. The Green-Lagrange strain at the critical location determined from the finite element analysis was used for evaluating the fatigue damage parameter of the natural rubber. Fatigue tests were performed using the 3D dumbbell specimens with different levels of maximum strain and various load. The basic mechanical properties test and the fatigue test of rubber specimens under the normal and elevated temperature were conducted. Fatigue life curves can be effectively represented by a following single function using the maximum Green-Lagrange strain. Fatigue lives of the natural rubber are predicted by using the fatigue damage parameters at the critical location. Predicted fatigue lives of the engine mount agreed fairly with the experimental fatigue lives a factor of two.

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