In this research, the effects of notch shape on the FATIGUE strength of 2024-T3 aluminum alloy notched specimens have been studied using experimental and MULTIAXIAL FATIGUE analysis. For this purpose, four set of specimens with different notch shape were prepared and then FATIGUE tests were carried out at various cyclic longitudinal load levels. Load controlled FATIGUE tests of mentioned specimens have been conducted on a 250kN servo-hydraulic Amsler H250 FATIGUE testing machine with the frequency of 10Hz. A nonlinear finite element ANSYS code was used to obtain stress and strain distribution in the specimens due to the longitudinal applied loads for all kinds of specimens. Estimation FATIGUE lives of the specimens were carried out with several different MULTIAXIAL FATIGUE criteria by means of local stress and strain distribution obtained from finite element analysis, i.e. KBM, FS, Crossland, VF and WY, by means of local stress and strain values obtained from finite element simulations. Results obtained from the MULTIAXIAL analysis revealed that among the applied criteria, the Crossland’s criterion has the best accuracy for all types of the specimens.

The present research has investigated the FATIGUE life of in-service steel patch welded joints by experimental/numerical approaches. To this end, three types of welded panels with similar Welding Procedure Specification but different cooling conditions were constructed. Subsequently, test samples cut from the main panels were subjected to FATIGUE tests. A novel approach involving continuous hardness measurement at the welding section was employed to predict the mechanical and FATIGUE properties of different zones in welded specimens. Firstly, the mechanical properties and FATIGUE parameters of various weld regions and heat affected zone were calculated using microhardness measurement and metallography images. Then, stress analysis was conducted in the Abaqus. The FATIGUE life was predicted using the stress and strain values obtained from the finite element analysis, the UVARM subroutine, and MULTIAXIAL FATIGUE modeling codes. The life estimations obtained from the numerical models were ultimately compared by experimental FATIGUE test results. The experimental tests showed that the samples cooled with water at a speed of 0.5 m/s had an increase in life, and the samples cooled with water at a speed of 1.5 m/s had a decrease in life compared to the samples cooled in air. Moreover, to predict the FATIGUE life, Brown-Miller-Marrow and Glinka criteria were used, respectively, and the results showed that these two criteria are able to predict the FATIGUE life with the maximum average error of 20.16% and 34.68%, respectively.

Engineering structures are usually exposed to cyclic MULTIAXIAL loading and subsequently to MULTIAXIAL FATIGUE. Different models and criteria with various capabilities have been proposed for predicting of MULTIAXIAL FATIGUE life. Selection of proper model by considering material, type of loading and operation condition of each engineering structure is a challenging issue of the life prediction process.In this paper, capability of some critical strain-based models for predicting the FATIGUE life are evaluated and compared. Then, based on the advantages and disadvantages of the investigated models, a new model is presented. In this study, experimental FATIGUE data for SNCM630 samples under axial torsional loading are used which is available in the literature. Results are compared to experimental data in order to validate the accuracy and capability of the new model in prediction of the FATIGUE life.

One of the main advantages for the increasing engineering application of composites in weight-critical structural applications is their high specific stiffness and strength. Composite materials behavior is complicated more than metallic material because of different mechanisms, damage growth rate and effect of them in each other. In this paper, a continuum damage mechanics based model is developed to simulate stiffness degradation and FATIGUE life prediction of laminated composites under FATIGUE loading conditions.Damage parameters are used to estimate the degradation of elastic properties in matrix, fiber and shear direction. The material properties of the damage evolution equations are derived by testing on 0o and 90o unidirectional plies and [0/90]s cross-ply laminate. To evaluate the model under MULTIAXIAL FATIGUE loading, arbitrary states of stress and stress ratio available results of experiments on unidirectional 90, 0 and 30 plies under FATIGUE loading conditions are used. Also, to evaluate the model for composite laminates with stress concentration results of experiments of pin-loaded cross-ply [04/904]s laminate are used. The obtained results show the capability of proposed model in FATIGUE life prediction of unidirectional and crossply laminates under uniaxial and MULTIAXIAL FATIGUE loading with different states of stress.

FATIGUE failure occurring in most engineering components, generally is related to MULTIAXIAL loadings. Variation in principal axes of stresses and strains in MULTIAXIAL loading causes additional hardening and this is assumed as the main reason of FATIGUE life decrease. The origin of MULTIAXIALity may have diverse reasons and may arise from MULTIAXIAL loading, complicated geometry or residual stresses. In the present study various MULTIAXIAL FATIGUE criteria were applied for predicting FATIGUE life of an alloy and by using the finite element method a hollow cylindrical specimen made of alloy GH4169 was simulated under strain controlled multi-axial loading at high temperature. Hysteresis loops derived from simulation results and estimated life have been validated and compared with reference sample experimental results. The results shows that approaches considering simultaneous effect of stress, strain and additional hardening, especially at high temperature loading condition, could better predict the life. Among the presented criteria, Fatemi-Kurath, Fatemi-Socie and energy criteria have closest predictions to experimental results.

The present paper studies the effect of creating a fillet on fretting FATIGUE strength of an axle, using different MULTIAXIAL FATIGUE criteria and fretting FATIGUE damage parameter. Finite element method is applied to obtain stress and strain in the axle and the results obtained from modeling are compared with the experimental test data available in literature. The results show that fretting FATIGUE strength of the axle and fracture area depends on the ratio of diameter to fillet radius. MULTIAXIAL FATIGUE criteria is almost capable of estimating the FATIGUE strength of the axle. However; the results obtained from investigating fretting FATIGUE damage parameter are almost in accordance with the results of experimental data and consequently fretting FATIGUE damage parameter can be appropriatelyused as a criterion for estimating fretting FATIGUE strength of the axles.

The objective of this paper is to evaluate the validity of commonly used multi axial FATIGUE criteria for different MULTIAXIAL loading conditions. The best criterion is identified through comparative analysis. The assessment is based on the experimental research findings of the SAE notched shaft, which is used as a benchmark. The relative performance of the three existing MULTIAXIAL FATIGUE theories based on the strain criteria and the critical plane approaches are investigated. There is no fixed strain life criterion that can predict the FATIGUE life best for different loading cases. Among all the critical plane models considered, Fatemi and Socie model gives best FATIGUE life prediction for both MULTIAXIAL in phase and 90° out of phase loading cases.

The aim of this study was to determine the psychometric characteristics of Millon Clinical MULTIAXIAL Inventory. The research method was descriptive in which 774 participants (311 patients, 463 normals) were selected through purposeful and simple random sampling, respectively. For gathering data, Millon clinical MULTIAXIAL inventory was utilized. Analysis of data revealed that reliability of this inventory via test-retest were 0.611-0.793 in patients and 0.795-0.972 in normals. Reliability using chronbach's alpha were 0.64-0.89. Positive prediction power for personality scales (0.13-0.47), for clinical scales (0.33-0.78), and negative prediction power for inventory (0.91-0.99), and total discrimination power (0.77-0.97) were found. In factor analyzing through principal factors and varimax rotation, 9 factors with eigenvalue more than 1 were found. They included: emotional distress, self-referring thoughts/paranoid projection, drug abuse, alcoholism, lack of emotional control/inhibition problems, rumination, sociability, trauma, passivity. On the basis of findings, it can be said that Millon clinical MULTIAXIAL Inventory-III gas sufficient reliability and validity to be used among people with psychological disorders.