Deflection (engineering)

About: Deflection (engineering) is a research topic. Over the lifetime, 30862 publications have been published within this topic receiving 298849 citations.

Finite-Element Analyses of Flexible Pavements

Abstract: This study illustrates the usefulness of the finite-element method in the analysis of three-layer pavement systems subjected to different types of loading. The method is capable of simulating the observed responses of pavements subjected to axle loads with different tire pressures, axle loads with different configurations, and axle loads traveling at different speeds. A variety of material constitutive models such as linear elastic, nonlinear elastic, and viscoelastic are employed in the analyses to describe the behavior of the pavement materials. Finite-element modeling of pavements, if validated, can be extremely useful, because it can be used directly to estimate primary response parameters without resorting to potentially costly field experiments. If accurate correlations between the calculated and the measured primary response parameters can be obtained, then the analytical model can be used to calculate primary response load equivalency factors, utilizing deflection-based or strain-based equivalency factor methods.

Analysis of FG-CNT reinforced composite conical panel subjected to moving load using Ritz method

Abstract: Forced vibration response of a conical panel subjected to the action of a moving load is investigated in the current research Panel is made from a carbon nanotube (CNT) reinforced composite where the CNTs as reinforcements are distributed either uniformly or functionally graded across the panel thickness Panel is formulated using the first order shear deformation shell theory and the Donnell kinematic assumptions It is subjected to a moving load whose path and velocity are both arbitrary The properties of the composite media are estimated according to a refined rule of mixtures approach The governing equations of motion of the shell are obtained according to the Ritz method where the shape functions are obtained according to the Gram-Schmidt process The developed equations with the aid of Ritz method are transformed into time-dependent ordinary differential equations whose solution is traced in time by means of the Newmark time marching scheme Numerical results are provided to explore the influences of semi-vertex and opening angles of the cone, geometrical parameters and also CNT characteristics of the shell It is shown that, dynamic deflection of the shell decreases significantly with the introduction of FG-X pattern of CNTs Furthermore, enrichment of the matrix with more CNTs alleviates the dynamic deflection of the conical shell

Shrinkage Restraint and Loading History Effects on Deflections of Flexural Members

Abstract: This paper examines the effects of shrinkage restraint cracking and loading history on deflection of reinforced concrete flexural members. Findings show that deflections of lightly reinforced members are highly sensitive to both shrinkage restraint cracking and loading history, while deflections of more heavily reinforced members are insensitive to these effects at full service load. Results of a deflection example are presented along with recommendations for changes to ACI 318. One recommended change is the adoption of a lower cracking moment than the one currently specified in the code to account for shrinkage restraint stresses. It is also recommended that the code evaluate deflection using an effective moment of inertia based on the full dead plus live service load to account for preloading from construction loads prior to installation of nonstructural elements. An evaluation of these changes show that the recommendations will have a significant influence on deflection of lightly reinforced concrete members.