Bending moment

About: Bending moment is a research topic. Over the lifetime, 14577 publications have been published within this topic receiving 158834 citations. The topic is also known as: bending moment.

Method for minimizing warp and die stress in the production of an electronic assembly

Abstract: A method of minimizing warp and die stress in the production of an electronic assembly includes connecting one surface of a die to a package, and connecting an opposite surface of the die to a lid disposed over a constraining ring that is mounted to the package. The lid has a size, shape and coefficient of thermal expansion (CTE) selected to generate a bending moment that opposes bending moments resulting from connecting the die to the package.

Effects of Modeling Soil Nonlinearity and Wall Installation on Back-Analysis of Deep Excavation in Stiff Clay

Abstract: This paper describes the application of two relatively simple models: a linear elastic–perfectly plastic Mohr–Coulomb and a nonlinear “brick” model for simulating the top–down construction of a multipropped excavation in the overconsolidated stiff–fissured Gault clay at Lion Yard, Cambridge, with and without wall installation effects modeled. Numerical results are evaluated through comparisons with the comprehensive case record at Lion Yard, Cambridge. The objectives of the comparisons are to illustrate the effects of modeling wall installation and soil nonlinearity inside the yield surface on geotechnical designs. These comparisons are thus focused on aspects in which the practicing engineers are most interested, including the bending moments and deflections of the diaphragm wall, the strut loads, and the ground movements around the excavation. The results of the comparison demonstrate that the use of a Mohr–Coulomb model with a “wished–in–place” wall can reasonably predict the maximum bending moments and deflections of the wall for design purposes once the input soil parameters are correctly estimated. However, it significantly overestimates strut loads and fails to estimate the general ground deformation pattern.

Evaluation of seismic performance of pile-supported models in liquefiable soils

Abstract: The seismic performance of four pile-supported models is studied for two conditions: (i) transient to full liquefaction condition i.e. the phase when excess pore pressure gradually increases during the shaking; (ii) full liquefaction condition i.e. defined as the state where the seismically-induced excess pore pressure equalises to the overburden stress. The paper describes two complementary analyses consisting of an experimental investigation carried out at normal gravity on a shaking table and a simplified numerical analysis, whereby the soil-structure interaction (SSI) is modelled through non-linear Winkler springs (commonly known as p-y curves). The effects of liquefaction on the SSI are taken into account by reducing strength and stiffness of the non-liquefied p-y curves by a factor widely known as p-multiplier and by using a new set of p-y curves. The seismic performance of each of the four models is evaluated by considering two different criteria: (i) strength criterion expressed in terms of bending moment envelopes along the piles; (ii) damage criterion expressed in terms of maximum global displacement. Comparison between experimental results and numerical predictions shows that the proposed p-y curves have the advantage of better predicting the redistribution of bending moments at deeper elevations as the soil liquefies. Furthermore, the proposed method predicts with reasonable accuracy the displacement demand exhibited by the models at the full liquefaction condition. However, disparities between computed and experimental maximum bending moments (in both transient and full liquefaction conditions) and displacement demands (during transient to liquefaction condition) highlight the need for further studies.