Finite element based fatigue analysis of 6082 Aluminum alloy under random loading

Mechanical and structural components are subject in the most cases during their services to random loading. For this reason, it is necessary to reduce the complex history of these kinds of loading in a series of constant amplitude cycles. There are several counting methods that lead to different results. Among all these methods, it is recognized that the Rainflow Cycle Counting method provides the most conservative results. In this paper, a finite elements analysis technique is presented to predict the fatigue life using this method associate with the S-N method which is used for high cycle fatigue applications that makes no distinction between initiation or growing a crack, but rather, predicts the total life to failure. Comparison between numerical and experimental results is considering in this paper.

Finite element based fatigue analysis of 6082 Aluminum alloy under random loading

Mechanical and structural components are subject in the most cases during their services to random loading. For this reason, it is necessary to reduce the complex history of these kinds of loading in a series of constant amplitude cycles. There are several counting methods that lead to different results. Among all these methods, it is recognized that the Rainflow Cycle Counting method provides the most conservative results. In this paper, a finite elements analysis technique is presented to predict the fatigue life using this method associate with the S-N method which is used for high cycle fatigue applications that makes no distinction between initiation or growing a crack, but rather, predicts the total life to failure. Comparison between numerical and experimental results is considering in this paper.

Numerical Analysis and Optimization of the Residual Stresses Distribution Induced by Cold Expansion Technique

Abstract. This paper presents a numerical investigation about the influence of mandrel shape on residual stresses induced by the cold expansion procedure. Thus, ball and tapered pin are used for cold expanding the plate. As, the entrance face presents the lowest residual stresses throughout the hole thickness, we propose to solve this problem by varying the mandrel taper degree, instead of applying a double expansion.  The obtained results show that the tapered pin is more suitable for the cold expansion. More, low taper increases the residual stresses at the entrance, reaching the values generated at the exit face

A 3D analysis of crack-front shape of asymmetric repaired aluminum panels with composite patches

Through this study, a numerical simulation based on 3D in order to investigate the effect of Crack-front shape on the stress intensity factor and fatigue crack growth behavior of center cracked aluminum plate repaired asymmetrically with a bonded composite patch. Consequently, Skew degree is a significant effect on stress intensity factor (SIF) distribution along the crack front in thick panels more than thin panels. Moreover, Fatigue life was calculated using different averages stress intensity factor of patched panel determined from the uniform crack front model and skew crack front model obtained from FEM and when comparing fatigue life values obtained from the finite element model with experimental values were shown a good agreement

Finite element modeling and analytical solution of a semi-elliptic crack's Jintegral

In this work, we first evaluate the J-integral rupture parameter as a function of various crack parameters (crack size, rod dimensions, intensity and nature of loads) for various crack form. In a second step, and in the base of the results obtained by the finite element method, we propose formulas of the factor shape, whose implementation remains rather simple and inexpensive in terms of time, effort and means to the engineer in order to predict evolution of the rupture behavior of a cylindrical component with a semielliptical crack emerging from the surface. The comparison of the proposed analytical solution showed a good performance relatively with results of the literature

Finite Elements Analysis of a Butterfly-Shaped Composite patch Repair and its Comparison to the Usual Shapes

A 3-D finite element analysis was conducted on a thin aluminum plate with a 45 ° inclined central crack.  A modeling of the bonding repair with composite patch of different shapes was carried out. In addition to the patch shapes studied in the literature, a new butterfly shape was proposed. The latter is defined by a length H, a width B and a neck C in the middle. The main objective is to analyze the effect of patch geometry on the rate of decrease of stress intensity factors. This rate is characterized by a coefficient R which combines between the mode I and the mode II of the rupture (KI and KII). Thus, an optimization of the patch shape is made with respect to the effectiveness in decreasing the stress intensity factor. The comparison between the results obtained with the different patch shapes has shown that the butterfly-shaped patch is more effective for relatively small surfaces. On the other hand, the extended octagon shape has been shown to be more effective for higher patch surfaces

Finite Elements Analysis of a Butterfly-Shaped Composite patch Repair and its Comparison to the Usual Shapes

A 3-D finite element analysis was conducted on a thin aluminum plate with a 45 ° inclined central crack.  A modeling of the bonding repair with composite patch of different shapes was carried out. In addition to the patch shapes studied in the literature, a new butterfly shape was proposed. The latter is defined by a length H, a width B and a neck C in the middle. The main objective is to analyze the effect of patch geometry on the rate of decrease of stress intensity factors. This rate is characterized by a coefficient R which combines between the mode I and the mode II of the rupture (KI and KII). Thus, an optimization of the patch shape is made with respect to the effectiveness in decreasing the stress intensity factor. The comparison between the results obtained with the different patch shapes has shown that the butterfly-shaped patch is more effective for relatively small surfaces. On the other hand, the extended octagon shape has been shown to be more effective for higher patch surfaces

Finite Elements Analysis of a Butterfly-Shaped Composite patch Repair and its Comparison to the Usual Shapes

A 3-D finite element analysis was conducted on a thin aluminum plate with a 45 ° inclined central crack.  A modeling of the bonding repair with composite patch of different shapes was carried out. In addition to the patch shapes studied in the literature, a new butterfly shape was proposed. The latter is defined by a length H, a width B and a neck C in the middle. The main objective is to analyze the effect of patch geometry on the rate of decrease of stress intensity factors. This rate is characterized by a coefficient R which combines between the mode I and the mode II of the rupture (KI and KII). Thus, an optimization of the patch shape is made with respect to the effectiveness in decreasing the stress intensity factor. The comparison between the results obtained with the different patch shapes has shown that the butterfly-shaped patch is more effective for relatively small surfaces. On the other hand, the extended octagon shape has been shown to be more effective for higher patch surfaces

Removal of 4-(2-pyridylazo)-Resorcinol from Aqueous Solution Using Natural and Activated Algerian Kaolin

International audienc

Fatigue life estimation of components with use a non-linear energy model coupled a finite element method

The work presents a non-linear fatigue computation method together with finite element method, in which energy parameter has been used. The Proposed model has been used for simulation computations, based on experimental testing of Al-2024 aluminum alloy specimens subjected to two types of loads, i.e. variable blocs loading and random loading. Computations of energy parameter value have been donebased on the results of FEM elastic–plastic analysis of cyclic properties of a material. A computing Matlab-based algorithm of the fatigue life prediction methodology was developed. The proposed damage indicator is connected cycle by cycle to the Wöhler curve. Cycles were counted with the rain-flow algorithm, and damage was accumulated with this model and with the Palmgren–Miner rule. On the grounds of which fatigue life has been read off from only characteristics of specimens. An experimental verification shows a satisfactory agreement between the fatigue life calculation results by the proposed methodology and test results. Estimated and experimental lives are found to exhibit good agreement