Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links wer...Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links were designed using steel grades with yield points ranging from high to low strengths. The objectives of the numerical analyses were to further investigate the non-linear behavior and to correlate the numerical results with experimental observations. Elasto-plastic as well as cyclic stress-strain material properties were incorporated to study the influence of material behavior on the overall shear link response. Non-linear monotonie analyses of the shear links incorporating the cyclic stress-strain steel properties resulted in similar trends in the response as the backbone curves recorded from the physical experiments. The numerical models of built-up shear links utilizing structural grade steels closely correlated to the experimentally recorded shear strength. Models utilizing low yield point steels overestimated the shear strength, which was caused by the characteristics of cyclic behavior of those steels. The detailed numerical models also allowed for investigation of the plastic strain demands on the different components of the link. It was shown that finite element models combined with appropriate stress-strain relationship may be used with confidence to check the design of shear links of different steel grades and sectional geometries.展开更多
Latent heat energy storage through phase-change materials(PCMs)is one possible strategy to control interior temperatures in buildings,improve thermal comfort,and passively reduce building energy use associated with he...Latent heat energy storage through phase-change materials(PCMs)is one possible strategy to control interior temperatures in buildings,improve thermal comfort,and passively reduce building energy use associated with heating and cooling.While PCMs integrated into building structure elements have been studied since the 1970s,challenges of integrating PCMs into building materials while maintaining their heat storage benefits have limited their application in practice.The recent introduction of microencapsulated phase-change materials provides the energy storage capability of PCMs in micron-scale,chemically-inert capsules that can be easily integrated into composite materials such as gypsum wallboard and concrete.The size and physical properties of microencapsulated PCMs suggest that they will behave similarly to filler materials in concrete.Such filler materials are generally less than 125μm in diameter and can increase concrete strength when added to a mix.This study uses the compressive strength of hardened concrete mixes with varying amounts of PCM to evaluate the effect of PCM addition on concrete structural integrity.展开更多
基金the Federal Highway Administration through the Highway Project at the Multidisciplinary Center for Earthquake Engineering Researchthe toll bridge retrofit program of the California Department of Transportation through the University of California,San Diego
文摘Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links were designed using steel grades with yield points ranging from high to low strengths. The objectives of the numerical analyses were to further investigate the non-linear behavior and to correlate the numerical results with experimental observations. Elasto-plastic as well as cyclic stress-strain material properties were incorporated to study the influence of material behavior on the overall shear link response. Non-linear monotonie analyses of the shear links incorporating the cyclic stress-strain steel properties resulted in similar trends in the response as the backbone curves recorded from the physical experiments. The numerical models of built-up shear links utilizing structural grade steels closely correlated to the experimentally recorded shear strength. Models utilizing low yield point steels overestimated the shear strength, which was caused by the characteristics of cyclic behavior of those steels. The detailed numerical models also allowed for investigation of the plastic strain demands on the different components of the link. It was shown that finite element models combined with appropriate stress-strain relationship may be used with confidence to check the design of shear links of different steel grades and sectional geometries.
基金supported by the Department of Energy under Award Number#DE-EE0003870.
文摘Latent heat energy storage through phase-change materials(PCMs)is one possible strategy to control interior temperatures in buildings,improve thermal comfort,and passively reduce building energy use associated with heating and cooling.While PCMs integrated into building structure elements have been studied since the 1970s,challenges of integrating PCMs into building materials while maintaining their heat storage benefits have limited their application in practice.The recent introduction of microencapsulated phase-change materials provides the energy storage capability of PCMs in micron-scale,chemically-inert capsules that can be easily integrated into composite materials such as gypsum wallboard and concrete.The size and physical properties of microencapsulated PCMs suggest that they will behave similarly to filler materials in concrete.Such filler materials are generally less than 125μm in diameter and can increase concrete strength when added to a mix.This study uses the compressive strength of hardened concrete mixes with varying amounts of PCM to evaluate the effect of PCM addition on concrete structural integrity.
