88 research outputs found

    Could time detect a faking-good attitude? A study with the MMPI-2-RF

    Get PDF
    Background and Purpose: Research on the relationship between response latency (RL) and faking in self-administered testing scenarios have generated contradictory findings. We explored this relationship further, aiming to add further insight into the reliability of self-report measures. We compared RLs and T-scores on the MMPI-2-RF (validity and restructured clinical [RC] scales) in four experimental groups. Our hypotheses were that: the Fake-Good Speeded group would obtain a different completion time; show higher RLs than the Honesty Speeded Group in the validity scales; show higher T-Scores in the L-r and K-r scales and lower T-scores in the F-r and RC scales; and show higher levels of tension and fatigue. Finally, the impact of the speeded condition in malingering was assessed. Materials and Methods: The sample was comprised of 135 subjects (M = 26.64; SD = 1.88 years old), all of whom were graduates (having completed at least 17 years of instruction), male, and Caucasian. Subjects were randomly assigned to four groups: Honesty Speeded, Fake-Good Speeded, Honesty Un-Speeded, and Fake-Good Un-Speeded. A software version of the MMPI-2-RF and Visual Analog Scale (VAS) were administered. To test the hypotheses, MANOVAs and binomial logistic regressions were run. Results: Significant differences were found between the four groups, and particularly between the Honest and Fake-Good groups in terms of test completion time and the L-r and K-r scales. The speeded condition increased T-scores in the L-r and K-r scales but decreased T-scores in some of the RC scales. The Fake groups also scored higher on the VAS Tension subscale. Completion times for the first and second parts of the MMPI-2-RF and T-scores for the K-r scale seemed to predict malingering. Conclusion: The speeded condition seemed to bring out the malingerers. Limitations include the sample size and gender bias

    Assessment of dynamic parameters of heavy-duty gears

    Get PDF
    The article provides an analysis of use of heavy-duty gear trains in the mining industry. It was revealed that it is necessary to create a dynamic model to calculate the acting stresses and durability in order to assess the dynamic parameters of the gear train. The article provides the results of use of Nastran software shell in terms of stress-strain behavior of the girth gear

    Effect of FORTA-FI Fibers on the Rutting Potential, Dynamic Modulus, Flow Number, and Fatigue of Asphalt Concrete

    Get PDF
    The effect of fiber- reinforcement on asphalt concrete mixes is better explored through laboratory performance testing. Two mixes were evaluated throughout this research. One mix was a standard West Virginia Department of Highways Wearing I, and the other was the Wearing I mix reinforced with FORTA- FIRTM fibers. The testing was done using the Asphalt Pavement Analyzer (APA) and the Asphalt Mixture Performance Tester (AMPT).;First, the rutting potential of the two mixes was determined using the APA. Next, the performance of the two mixes was compared using the AMPT. The tests performed on the AMPT determined the dynamic modulus, flow number, and fatigue characteristics of the two mixes. Dynamic modulus master curves were developed using Bonaquist\u27s MasterSolver Version 2.2 to compare the stiffness of the two mixes. The flow number was evaluated using the Data Smoothing Method and the Francken Model Method to compare the rutting potential of the two mixes. Last, Instrotek\u27s Alpha-Fatigue(TM) software was used to determine the coefficients needed to model the fatigue behavior of the mixes

    Effect of cylic stress range on crack growth of aluminium alloy under axial loading

    Get PDF
    This thesis presented about the fatigue life of the material, which is focus on aluminium alloy. There are some important analysis needs to be done including stress analysis, and also fatigue analysis. People might prefer predict the fatigue life of aluminium alloy using experimental approach. But in this thesis, it comes out with different ways, by using software. The software used is MSC PATRAN with MSC NASTRAN as a solver and MSC Fatigue. The model is developed using the SOLIDWORKS. The results from initial analysis will be proceeding with second analysis which is fatigue simulation. Finally, the crack growth graph will be constructed. The effect of stress ranges of aluminium alloys on fatigue crack growth rate was simulated using the Compact Tension specimen as a model. The Fatigue Crack Growth curve, da/dn as a function of stress intensity factor, ΔK was plotted in order to analyze the crack growth properties of aluminium alloys. It has been done using MSC FATIGUE software. 4 different stress ranges were selected in range (4-10) kN in order to investigate the effect of stress range on crack growth rates. The model were simulated by means of Mode I loading in constant temperature and frequency. The constant value of C and gradient, m according to Modified Paris Law equation, are 1.2E-10 and 4.06 respectively. The life cycle graph (S-N curve) of aluminium alloy under this simulation will be compared to the established life cycle graph. It was show that the aluminium alloys have endurance limit of 95MPa

    Numerical and analytical studies of low cycle fatigue behavior of 316 LN austenitic stainless steel

    Get PDF
    Mechanical components are frequently subjected to severe cyclic pressure and/or temperature loadings. Therefore, numerical and analytical low cycle fatigue methods become widely used in the field of engineering to estimate the design fatigue lives. The primary aim of this work is to evaluate the accuracy of the most commonly used numerical and analytical low cycle fatigue life methods for specimens made of 316 LN austenitic stainless steel and subjected to fully reversed uniaxial tension-compression loading, in the room temperature condition. It was found that both Maximum shear strain and Brown-Miller criterions result in a very conservative estimation for uniaxially loaded specimens, however, Maximum shear strain criteria provides better results compared to the Brown-Miller criteria. The total strain energy density approach was also used, and both the Masing and non-Masing analysis were adopted in this study. It is found that the Masing model provides conservative fatigue lives, and non-Masing model results in a more realistic fatigue life prediction for 316 LN stainless steel for both low and high strain amplitude. The fatigue design curves obtained from the commonly used analytical low cycle fatigue equations were reexamined for 316 LN SS. The obtained design curves from Langer model and its modified versions are non-conservative for this type of material. Consequently, the authors suggest new optimized parameters to fit the given test data. The obtained curve using the currently suggested parameters is in better agreement with the experimental data for 316 LN SS

    DEVELOPMENT OF AN ALERT SOFTWAREOF LAPTOP FOR FATIGUE WARNING AND HEALTH CARE

    Get PDF
    Employee health care is a focusing topic these years. Using the laptop for a long time will damage human’s health seriously, especial to human’s eye, for example, will cause maculopathy. Using the alert software of laptop, we can warn user to take a rest when he detects tired symptom of user

    Evaluating the protocol of the spectrum of hot mix asphalt mixes produced in West Virginia

    Get PDF
    Reviewing asphalt concrete plant-produced mixes in a laboratory setting provides further insight into pavement characteristics. Nine mix designs provided from five hot mix asphalt plant producers were evaluated throughout this research. Five mixes were Wearing I and four mixes were Base II/19 mm each of which contained various aggregate sources. First, the determination of bulk specific gravity was performed using three methods: Saturated Surface-Dry, CoreLok, and Dimensional (volumetric mass density). Moreover, assessing a mix\u27s inherent capability to be uniformly compacted is integral in both laboratory and field evaluations. The nine mix designs were assessed for uniformity following AASHTO PP 60 standard.;Furthermore, the Asphalt Mixture Performance Tester (AMPT) is a new performance testing machine that has dynamic modulus, flow number, and fatigue testing capabilities. This research focused on using the AMPT to determine dynamic modulus, fatigue characterization, and flow number values of the asphalt mixes. Master curves were developed using Mastersolver Version 2.2 to review the stiffness of the mixes. Asphalt Pavement Hierarchical Analysis Toolbox -- Fatigue Program (Alpha-FatigueTM software) was utilized to determine fatigue coefficients used to model the traditional fatigue equation. Yang Huang\u27s KENPAVE was used to develop a range of strain-modulus curves. Next, AMPT dynamic modulus values and fatigue K-value outputs were then compared using the KENPAVE strain outputs at a specified frequency level. Lastly, flow number was evaluated for rutting resistance and compared among mix designs using two methods: data smoothing method and the Francken Model

    Stress Analysis of Multi Leaf Spring by Using Experimental Method

    Get PDF
    Leaf springs are used in vehicles for suspension purpose in all type of vehicles. Ample amount of work has been done on the analysis of leaf spring. Researcher focused on the  analysis of stresses developed in spring by using different FEM tool also several worked on predict fatigue life of leaf spring. After review of available literature on leaf spring it is found that the very few literature is available on analysis of springs used for light commercial vehicle. This paper describes the static analysis of multi leaf spring by using experimental method i.e. strain gauge under various loading conditio

    ProFatigue: a software program for probabilistic assessment of experimental fatigue data sets

    Get PDF
    In this work, the software program ProFatigue is presented as a practical tool for derivation of probabilistic S-N and ε-N fields from experimental fatigue data. The program provides an estimation of the parameters involved in the regression probabilistic Weibull fatigue model developed by the authors, allowing an advantageous application of both fields to the stress or strain based approaches in the fatigue design of structures and mechanical components. An extension to the analysis of more complex and varied lifetime problems as thermomechanical, multiaxial and fretting fatigue is possible by adopting suitable damage parameters proposed in the literature as driving force. Application to probabilistic assessment of cumulative damage and further program enhancement are now envisaged
    • …
    corecore