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Structural Performance (structural + performance)

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Engineering	100%

Selected Abstracts

Seismic behaviour of hybrid systems made of PR composite frames coupled with dissipative bracings

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 6 2008
C. Amadio
Abstract The paper investigates the dynamic behaviour of hybrid systems made of partially restrained (PR) steel,concrete composite frames coupled with viscoelastic dissipative bracings. A numerical model that accounts for both the resisting mechanisms of the joint and the viscoelastic contribution of the dissipative bracing is introduced and briefly discussed. The model is first validated against experimental outcomes obtained on a one-storey two-bay composite frame with partial strength semi-rigid joints subjected to free vibrations. A number of time-history analyses under different earthquake ground motions and peak ground accelerations are then carried out on the same type of frame. The purpose is to investigate the influence of the type of beam-to-column connection and property of the viscoelastic bracing on the performance of the hybrid system. The inherent stiffness of the bare PR frame and the plastic hysteresis of the beam-to-column joints, which always lead to only limited damage in the joint, are found to provide a significant contribution to the overall structural performance even under destructive earthquakes. This remark leads to the conclusion that the viscoelastic bracing can be effectively used within the hybrid system. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Near-fault ground motions, and the response of elastic and inelastic single-degree-of-freedom (SDOF) systems

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 9 2004
G. P. Mavroeidis
Abstract In order to investigate the response of structures to near-fault seismic excitations, the ground motion input should be properly characterized and parameterized in terms of simple, yet accurate and reliable, mathematical models whose input parameters have a clear physical interpretation and scale, to the extent possible, with earthquake magnitude. Such a mathematical model for the representation of the coherent (long-period) ground motion components has been proposed by the authors in a previous study and is being exploited in this article for the investigation of the elastic and inelastic response of the single-degree-of-freedom (SDOF) system to near-fault seismic excitations. A parametric analysis of the dynamic response of the SDOF system as a function of the input parameters of the mathematical model is performed to gain insight regarding the near-fault ground motion characteristics that significantly affect the elastic and inelastic structural performance. A parameter of the mathematical representation of near-fault motions, referred to as ,pulse duration' (TP), emerges as a key parameter of the problem under investigation. Specifically, TP is employed to normalize the elastic and inelastic response spectra of actual near-fault strong ground motion records. Such normalization makes feasible the specification of design spectra and reduction factors appropriate for near-fault ground motions. The ,pulse duration' (TP) is related to an important parameter of the rupture process referred to as ,rise time' (,) which is controlled by the dimension of the sub-events that compose the mainshock. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Die shape design optimization of sheet metal stamping process using meshfree method

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2001
Nam Ho Kim
Abstract A die shape design sensitivity analysis (DSA) and optimization for a sheet metal stamping process is proposed based on a Lagrangian formulation. A hyperelasticity-based elastoplastic material model is used for the constitutive relation that includes a large deformation effect. The contact condition between a workpiece and a rigid die is imposed through the penalty method with a modified Coulomb friction model. The domain of the workpiece is discretized by a meshfree method. A continuum-based DSA with respect to the rigid die shape parameter is formulated using a design velocity concept. The die shape perturbation has an effect on structural performance through the contact variational form. The effect of the deformation-dependent pressure load to the design sensitivity is discussed. It is shown that the design sensitivity equation uses the same tangent stiffness matrix as the response analysis. The linear design sensitivity equation is solved at each converged load step without the need of iteration, which is quite efficient in computation. The accuracy of sensitivity information is compared to that of the finite difference method with an excellent agreement. A die shape design optimization problem is solved to obtain the desired shape of the workpiece to minimize spring-back effect and to show the feasibility of the proposed method. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Predictive mechanical performance evaluation of consumer food cans using stereolithography models

PACKAGING TECHNOLOGY AND SCIENCE, Issue 1 2003
D. Karalekas
Abstract The development of new metal food containers can be a technologically challenging and costly process. Understanding the interplay between the major design characteristics and requirements affecting the product's final structural capability is paramount to achieving an optimum design proposition. As a result, computer-based simulation has been employed by industry to assess a container's performance under a variety of load conditions, including axial load and panelling of cans. In this paper, the feasibility of a new approach for addressing the effects of design parameters on the structural performance of containers under development is investigated. The evaluation methodology is based on structural testing of stereolithography-built physical prototypes of a rigid metal container used for coffee packaging. It is shown that the experimentally obtained findings are in accordance to those resulting from computational simulation. This method can be used to support the development of existing and new metal containers. Copyright ©2003 John Wiley & Sons, Ltd. [source]

Thermal properties of lightweight-framed construction components at elevated temperatures

FIRE AND MATERIALS, Issue 3 2005
Noureddine Bénichou
Abstract Fire resistance behaviour of lightweight-framed assemblies is determined by defining the thermal and structural performances of the assembly when exposed to fire. To adequately model thermal behaviour in a lightweight wood-framed assembly, thermal properties of the components of the assembly at elevated temperatures must be well defined. This paper presents results of measurements of thermal properties at elevated temperatures of construction materials commonly used to build lightweight wood-framed assemblies that were conducted at the National Research Council of Canada since 1990. The test results, in graphical form, are given as a function of temperature for thermal conductivity, specific heat, mass loss and thermal expansion/contraction for wood, gypsum and insulation. In addition, the effects of temperature on the thermal conductivity, specific heat, mass loss and thermal expansion/contraction of these materials are discussed. Finally, in addition to providing a resource of information, this paper also identifies the additional thermal property tests required to complete the matrix of information. Copyright © 2005 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]