Double axis fatigue life prediction based on finite element analysis for aluminum alloy wheels
The basic situation was introduced firstly on the wheel double axis fatigue (abbreviated to WDAF) testing. Then the basic process to carry out the finite element analysis and the fatigue life prediction on the WDAF testing were introduced briefly. Subsequently, a typical wheel was taken as an example to implement the finite element fatigue life prediction for the WDAF testing of the aluminum alloy wheel. Finally, an initial criteria was proposed for the WDAF life prediction based on the analytical results from FEA for several wheels.
Evaluation of fatigue life of aluminium alloy wheels under bending loads
This paper presents the details of S–N curve for aluminium alloy (Al) A356.2-T6 and fatigue life of alloy wheels under bending load of cornering fatigue test (CFT). Development of S–N curve has been carried out by conducting rotary bending fatigue test at different stress levels as per Standards IS 5075. The rotary bending fatigue test has been performed under constant amplitude fatigue loading. The CFT of the wheel in normal driving mode has been carried out as per the procedure given in Japanese Industrial Standard Disc Wheels (JIS D_4103). It has been observed from the test that the cracks are initiated at the spoke and hub joining area closer to spanner hole on the front face of the wheel. Fatigue life of the alloy wheel has been predicted by finite element analysis (FEA), simulating the realistic test conditions. From finite element analysis, it has been observed that the maximum stress occurs at the mounting face of the wheel. Further, it has been observed that there is significant difference between the computed fatigue life and experimental value. Parametric study has been carried out for reliable fatigue life estimation and proposed an appropriate safety factor for fatigue life estimation under rotary bending test.
The role of prolactin in andrology: what is new?
Prolactin (PRL) has been long deemed as a hormone involved only in female reproduction. However, PRL is a surprising hormone and, since its identification in the 1970s, its attributed functions have greatly increased. However, its specific role in male health is still widely unknown. Recently, low PRL has been associated with reduced ejaculate and seminal vesicle volume in infertile subjects. In addition, in men consulting for sexual dysfunction, hypoprolactinemia has been associated with erectile dysfunction and premature ejaculation, findings further confirmed in the general European population and infertile men. Several metabolic derangements, recapitulating metabolic syndrome, have also been associated with low PRL both in men with sexual dysfunction and from the general European population. In men with sexual dysfunction, followed-up for more than 4 years, low PRL was identified as an independent predictor of the incidence of major adverse cardiovascular events. Finally, an association with anxiety or depressive symptoms has been found in men with sexual dysfunction and from the general European population. While a direct role for impaired PRL function in the pathogenesis of these reproductive, sexual, metabolic and psychological disorders is conceivable, the possibility that low PRL is a mirror of an increased dopaminergic or a decreased serotonergic tone cannot be ruled-out. Hyperactivity of the dopaminergic system can explain only a few of the aforementioned findings, whereas a hypo-serotonergic tone fits well with the clinical features associated with low PRL, and there is significant evidence supporting the hypothesis that PRL could be a mirror of serotonin in the brain.