Transverse and longitudinal vibrations of a frame structure due to a moving trolley and the hoisted object using moving finite element

This paper aims at presenting a technique to replace the moving load by an equivalent moving finite element so that both the transverse and the longitudinal inertial effects due to the moving mass may easily be taken into account simultaneously. Where the mass, damping and stiffness matrices of the moving finite element are determined by the transverse () inertia force, Coriolis force and centrifugal force of the moving mass, respectively. From the numerical examples illustrated, it has been found that, in addition to the conventional transverse () responses, the inertial effects of the moving load also affect the longitudinal () responses of the portal-frame structure significantly.     

Report of the Italian inter-laboratories comparison of high dc resistance on the calibration of a and a resistors

A national comparison of high dc resistance at and level was organized by the Electromagnetic Division of National Institute of Metrological Research (INRIM, Italy) and piloted by the high dc resistance Laboratory of the same Division. This comparison took place between January and April 2008 with the participation of 8 Secondary Laboratories accredited by the Italian Service of Accreditation of Calibration Laboratories (SIT). The travelling package included one wire-wound standard and one thick film-type standard in a wooden anti-shock container designed by INRIM. The obtained results indicate that the relative differences at and between each Laboratory’s value and the respective reference value are all within the expanded relative uncertainties of these differences at a 2σ confidence level.     

Prediction of forming limit curves of sheet metals using Hill’s 1993 user-friendly yield criterion of anisotropic materials

A user-friendly yield criterion was proposed by Hill in 1993, which utilizes five independent material parameters in representing the yield locus. In the present investigation, an attempt is made to analyze forming limits in sheet metals based on this yield criterion and the M–K approach. Comparison of the predicted results with experimental data indicates that Hill’s 1993 yield criterion is able to characterize the localized necking of both aluminum and AK steel. A parametric study is carried out to investigate the influence of material parameters on forming limits, which shows that the shape of the yield locus has a significant influence on limit strains.