Experimental and Finite Element Analysis for Multi-lead Rubber Bearings:A Comparative Study

The mechanical properties of multi-lead rubber bearings （MLRBs） were investigated by experiment and finite element analysis. First, the vertical stiffness, horizontal stiffness and yielded shear force were tested for four MLRB specimens and two specimens of the single-lead rubber bearings （ SLRBs）. Then, the MLRBs were modeled by the explicit finite element analysis software ANSYS/ LS-DYNA, in order to evaluate the horizontal force-displacement hysteretic curves under static vertical and dynamical horizontal loadings. The disagreement between the tested and theoretical values was less than 11.4%, and MLRBs and SLRBs were similar in vertical stiffness, pre-yield stiffness and yield stiffness.

Some aspects affecting the response of RC compartment structures subjected to internal blast loads

Protective compartments are typically used to protect some specific structures from internal explosions,such as industrial buildings that contain devices that may explode in certain circumstances.This research investigates how the response of reinforced concrete(RC)compartment structures subjected to internal blast loads are affected by the following aspects:introduction of material nonlinearity in the analysis,reinforcement ratio,and aspect ratio of the compartment.To achieve this goal,a calibrated and sophisticated FE numerical model is introduced,and a parametric study for the intended aspects is carried out.A discussion of the results and conclusions are offered,which show the role of each aspect in the dynamic performance of the compartment structures.The main conclusions are as follows:introduction of material nonlinearity in this type of analysis and for these structures is very important and significant in obtaining accurate outputs that are similar to actual behavior;the reinforcement ratio has a significant effect on the response and its effect varies depending on the thickness of the compartment;in general,increasing the reinforcement ratio enhances the behavior and reduces the stresses in the compartment;and the aspect ratio of the compartment does not show a clear pattern on the response of such structures under internal blast loads.

Numerical damage evaluation of perforated steel columns subjected to blast loading

The structural performance of perforated steel columns(PSCs)is significantly more complex than the one of solid web I-shaped elements under the diversity of blast loading scenarios.The damage criterion of PSCs is not only related to initial deformation response during the blast but also the residual axial load capacity and it can be considered as a reliable index after the blast effects.Therefore,the PSCs damages will be studied in two stages;direct and post blast effects.In the present study,the dynamic response of PSCs was numerically evaluated under different levels of blast threats using LS-DYNA software.Extensive explicit finite element(FE)analyses are carried out to investigate the effect of various parameters,such as web opening shapes,boundary conditions and strengthening details on the damage index and toughness of the PSCs compared to the parent steel sections.The results of the comparative study show that the damage and toughness decrease when the support condition changes from pinned to fixed ends through the two stages of loadings.PSCs give high toughness compared to its parent sections during blast shock stage while,a remarkable decrease in toughness is observed during the application of axial gravity after blast shock.Furthermore,the web opening shapes have slight effects on the global dynamic behavior of PSCs,particularly in terms of residual capacity.On the contrary,the retrofitting strategy using both closed holes at end and vertical stiffeners have an effective enhancement to get higher toughness in case of the extreme blasts.

A new computational approach for modeling diffusion tractography in the brain

Computational models provide additional tools for studying the brain,however,many techniques are currently disconnected from each other.There is a need for new computational approaches that span the range of physics operating in the brain.In this review paper,we offer some new perspectives on how the embedded element method can fill this gap and has the potential to connect a myriad of modeling genre.The embedded element method is a mesh superposition technique used within finite element analysis.This method allows for the incorporation of axonal fiber tracts to be explicitly represented.Here,we explore the use of the approach beyond its original goal of predicting axonal strain in brain injury.We explore the potential application of the embedded element method in areas of electrophysiology,neurodegeneration,neuropharmacology and mechanobiology.We conclude that this method has the potential to provide us with an integrated computational framework that can assist in developing improved diagnostic tools and regeneration technologies.