Computational simulation of steel moment frame to resist progressive collapse in fire

2016 ◽  
Vol 7 (4) ◽  
pp. 286-305 ◽  
Author(s):  
Ha Nguyen ◽  
Ann E. Jeffers ◽  
Venkatesh Kodur
Keyword(s):  
Experimental Data ◽  
Large Scale ◽  
Progressive Collapse ◽  
Computational Simulation ◽  
Three Dimensional ◽  
Fe Model ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Fixed Temperature ◽  
Content Type

Purpose This paper aims to address a need for improving the structural resilience to multi-hazard threats including fire and progressive collapse caused by the loss of a column. Design/methodology/approach The focus is on a steel moment frame that uses welded-unreinforced flange-bolted web connections between the beams and columns. A three-dimensional finite element (FE) model was created in ABAQUS with temperature-dependent properties for steel based on the Eurocode. The model was validated against experimental data at ambient and elevated temperature. Findings The failure mechanisms in the FE model were consistent with experimental observations. Two scenarios were considered: fixed load with increasing temperature (i.e. simulating column failure prior to fire) and fixed temperature with increasing load (i.e. simulating column failure during fire). Originality/value A macro element (or component-based) model was also introduced and validated against the FE model and the experimental data, offering the possibility of analyzing large-scale structural systems with reasonable accuracy and improved computational efficiency.

scholarly journals MACRO-ELEMENT MODEL OF A STEEL MOMENT FRAME SUBJECTED TO FIRE-INDUCED COLUMN LOSS

2016 ◽  
Author(s):  
Ha Nguyen ◽  
Ann E. Jeffers ◽  
Venkatesh Kodur
Keyword(s):  
Progressive Collapse ◽  
Experimental Tests ◽  
Element Model ◽  
Fe Model ◽  
Structural System ◽  
Moment Frame ◽  
Moment Connections ◽  
Steel Moment Frame ◽  
Collapse Mechanisms ◽  
Macro Element

A progressive collapse mitigation strategy is to ensure load redistribution when a column fails due to fire. The study seeks to understand whether welded unreinforced flange-bolted web (WUF-B) moment connections can effectively redistribute loads in a structural system subjected to fire when a critical column is lost. A component (or macro-element) model was derived to simulate the WUF-B connection and validated against experimental tests and high-resolution finite element (FE) models of subassemblies at room temperature and at elevated temperature. The component model was then utilized in a 2D macro FE model of a ten-story steel-framed building subjected to the loss of a column during long fire exposure. This paper presents the collapse mechanisms and quantifies structural performance based on acceptance criteria. A parametric study on location of column loss and fire occurrence is also included.

Thermo-mechanical coupling particle simulation of three-dimensional large-scale non-isothermal problems

2017 ◽  
Vol 34 (5) ◽  
pp. 1551-1571 ◽  
Author(s):  
Ming Xia
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Simulation Method ◽  
Particle Simulation ◽  
Similarity Criteria ◽  
Particle Model ◽  
Length Scale ◽  
Content Type ◽  
Mechanical Coupling ◽  
Particle Simulation Method

Purpose The main purpose of this paper is to present a comprehensive upscale theory of the thermo-mechanical coupling particle simulation for three-dimensional (3D) large-scale non-isothermal problems, so that a small 3D length-scale particle model can exactly reproduce the same mechanical and thermal results with that of a large 3D length-scale one. Design/methodology/approach The objective is achieved by following the scaling methodology proposed by Feng and Owen (2014). Findings After four basic physical quantities and their similarity-ratios are chosen, the derived quantities and its similarity-ratios can be derived from its dimensions. As the proposed comprehensive 3D upscale theory contains five similarity criteria, it reveals the intrinsic relationship between the particle-simulation solution obtained from a small 3D length-scale (e.g. a laboratory length-scale) model and that obtained from a large 3D length-scale (e.g. a geological length-scale) one. The scale invariance of the 3D interaction law in the thermo-mechanical coupled particle model is examined. The proposed 3D upscale theory is tested through two typical examples. Finally, a practical application example of 3D transient heat flow in a solid with constant heat flux is given to illustrate the performance of the proposed 3D upscale theory in the thermo-mechanical coupling particle simulation of 3D large-scale non-isothermal problems. Both the benchmark tests and application example are provided to demonstrate the correctness and usefulness of the proposed 3D upscale theory for simulating 3D non-isothermal problems using the particle simulation method. Originality/value The paper provides some important theoretical guidance to modeling 3D large-scale non-isothermal problems at both the engineering length-scale (i.e. the meter-scale) and the geological length-scale (i.e. the kilometer-scale) using the particle simulation method directly.

scholarly journals 300-Fold Increase in Production of the Zn2+-Dependent Dechlorinase TrzN in Soluble Form via Apoenzyme Stabilization

2014 ◽  
Vol 80 (13) ◽  
pp. 4003-4011 ◽  
Author(s):  
Colin J. Jackson ◽  
Christopher W. Coppin ◽  
Paul D. Carr ◽  
Alexey Aleksandrov ◽  
Matthew Wilding ◽  
...  
Keyword(s):  
Soluble Protein ◽  
Metal Ion ◽  
Large Scale ◽  
Computational Simulation ◽  
Active Form ◽  
Fold Increase ◽  
Soluble Form ◽  
Scale Production ◽  
Content Type ◽  
The Stability

ABSTRACTMicrobial metalloenzymes constitute a large library of biocatalysts, a number of which have already been shown to catalyze the breakdown of toxic chemicals or industrially relevant chemical transformations. However, while there is considerable interest in harnessing these catalysts for biotechnology, for many of the enzymes, their large-scale production in active, soluble form in recombinant systems is a significant barrier to their use. In this work, we demonstrate that as few as three mutations can result in a 300-fold increase in the expression of soluble TrzN, an enzyme fromArthrobacter aurescenswith environmental applications that catalyzes the hydrolysis of triazine herbicides, inEscherichia coli. Using a combination of X-ray crystallography, kinetic analysis, and computational simulation, we show that the majority of the improvement in expression is due to stabilization of the apoenzyme rather than the metal ion-bound holoenzyme. This provides a structural and mechanistic explanation for the observation that many compensatory mutations can increase levels of soluble-protein production without increasing the stability of the final, active form of the enzyme. This study provides a molecular understanding of the importance of the stability of metal ion free states to the accumulation of soluble protein and shows that differences between apoenzyme and holoenzyme structures can result in mutations affecting the stability of either state differently.

The Sliding Hinge Joint: Final Steps towards an Optimum Low Damage Seismic-Resistant Steel System

2018 ◽  
Vol 763 ◽  
pp. 751-760 ◽  
Author(s):  
Shahab Ramhormozian ◽  
George Charles Clifton ◽  
Gregory A. MacRae ◽  
Hsen Han Khoo
Keyword(s):  
Large Scale ◽  
Limit State ◽  
Model Development ◽  
Research Work ◽  
Research Programme ◽  
Service Condition ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Hinge Joint ◽  
Moment Resisting

The Sliding Hinge Joint with Asymmetric Friction Connectors (SHJ), to give its full name, is a semi-rigid moment resisting joint used between the beams and columns of a moment-resisting steel frame and also at the column base between the column and the ground. It’s performance is intended to be as follows: 1) On completion of construction, rigid under serviceability limit state conditions, 2) During a severe earthquake, allowing controlled rotation between the column and the beam or foundation on designated friction sliding planes within the connection, then 3) Returning to its rigid in-service condition at the end of the severe shaking with the building returning to its pre-earthquake position (self-centering). During its development and proof of concept through large scale testing, the initial results showed that the SHJ as originally designed and detailed performs 1) and 2) very well, but the bolts in the friction sliding planes loose much of their original installed bolt tension during significant sliding, lowering the level at which rotation within the joint will occur post severe earthquake. A concerted research programme of component testing, analytical model development and numerical modelling in recent years has developed solutions to the bolt tension loss issue as well as enhanced the joint’s performance to deliver dependable self-centering capability for the building. This work marks the final steps towards developing an optimum low damage seismic-resisting steel moment frame system. This paper presents key findings from the research work and general recommendations for the optimum performing sliding hinge joint.

scholarly journals Hope for the Best, Prepare for the Worst: Response of Tall Steel Buildings to the ShakeOut Scenario Earthquake

2011 ◽  
Vol 27 (2) ◽  
pp. 375-398 ◽  
Author(s):  
Matthew Muto ◽  
Swaminathan Krishnan
Keyword(s):  
Los Angeles ◽  
Three Dimensional ◽  
Steel Buildings ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Damage Scenario ◽  
San Gabriel Valley ◽  
San Fernando ◽  
Simulated Ground Motions ◽  
Available Information

This work represents an effort to develop one plausible realization of the effects of the scenario event on tall steel moment-frame buildings. We have used the simulated ground motions with three-dimensional nonlinear finite element models of three buildings in the 20-story class to simulate structural responses at 784 analysis sites spaced at approximately 4 km throughout the San Fernando Valley, the San Gabriel Valley, and the Los Angeles Basin. Based on the simulation results and available information on the number and distribution of steel buildings, the recommended damage scenario for the ShakeOut drill was 5% of the estimated 150 steel moment-frame structures in the 10–30 story range collapsing, 10% red-tagged, 15% with damage serious enough to cause loss of life, and 20% with visible damage requiring building closure.

Design of a rotor blade tip for the investigation of dynamic stall in the transonic wind-tunnel Göttingen

2016 ◽  
Vol 120 (1232) ◽  
pp. 1509-1533 ◽  
Author(s):  
B. Lütke ◽  
J. Nuhn ◽  
Y. Govers ◽  
M. Schmidt
Keyword(s):  
Experimental Data ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Numerical Data ◽  
Dynamic Stall ◽  
Navier Stokes ◽  
Fe Model ◽  
Stress Distributions ◽  
Cfd Simulations ◽  
Blade Tip

ABSTRACTThe aerodynamic and structural design of a pitching blade tip with a double-swept planform is presented. The authors demonstrate how high-fidelity finite element (FE) and computational fluid dynamic (CFD) simulations are successfully used in the design phase. Eigenfrequencies, deformation, and stress distributions are evaluated by means of a three-dimensional (3D) FE model. Unsteady Reynolds-averaged Navier-Stokes (RANS) simulations are compared to experimental data for a light dynamic stall case atMa= 0.5,Re= 1.2 × 106. The results show a very good agreement as long as the flow stays attached. Tendencies for the span-wise location of separation are captured. As soon as separation sets in, discrepancies between experimental and numerical data are observed. The experimental data show that for light dynamic stall cases atMa= 0.5, a factor of safety ofFoS= 2.0 is sufficient if the presented simulation methods are used.

Process modeling, joint-property characterization and construction of joint connectors for mechanical fastening by self-piercing riveting

2014 ◽  
Vol 10 (4) ◽  
pp. 631-658 ◽  
Author(s):  
Mica Grujicic ◽  
Jennifer Snipes ◽  
S. Ramaswami ◽  
Fadi Abu-Farha
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Large Scale ◽  
Constitutive Relations ◽  
Computational Cost ◽  
Three Dimensional ◽  
Modeling And Simulations ◽  
Content Type ◽  
Material Parameters ◽  
Computational Analyses

Purpose – The purpose of this paper is to propose a computational approach in order to help establish the effect of various self-piercing rivet (SPR) process and material parameters on the quality and the mechanical performance of the resulting SPR joints. Design/methodology/approach – Toward that end, a sequence of three distinct computational analyses is developed. These analyses include: (a) finite-element modeling and simulations of the SPR process; (b) determination of the mechanical properties of the resulting SPR joints through the use of three-dimensional, continuum finite-element-based numerical simulations of various mechanical tests performed on the SPR joints; and (c) determination, parameterization and validation of the constitutive relations for the simplified SPR connectors, using the results obtained in (b) and the available experimental results. The availability of such connectors is mandatory in large-scale computational analyses of whole-vehicle crash or even in simulations of vehicle component manufacturing, e.g. car-body electro-coat paint-baking process. In such simulations, explicit three-dimensional representation of all SPR joints is associated with a prohibitive computational cost. Findings – It is found that the approach developed in the present work can be used, within an engineering optimization procedure, to adjust the SPR process and material parameters (design variables) in order to obtain a desired combination of the SPR-joint mechanical properties (objective function). Originality/value – To the authors’ knowledge, the present work is the first public-domain report of the comprehensive modeling and simulations including: self-piercing process; virtual mechanical testing of the SPR joints; and derivation of the constitutive relations for the SPR connector elements.

Tourism demonstration system for large-scale museums based on 3D virtual simulation technology

2020 ◽  
Vol 38 (2) ◽  
pp. 367-381
Author(s):  
Yongcai Hu ◽  
Wei Sun ◽  
Xigang Liu ◽  
Quan Gan ◽  
Jie Shi
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Virtual Simulation ◽  
Simulation Technology ◽  
Large Space ◽  
Content Type ◽  
3D Network ◽  
Wide Range ◽  
3D Scene

Purpose The purpose of this study is to enhance audience experience in museum by using three-dimensional (3D) virtual simulation technology. Design/methodology/approach In this study, a large space museum building tourism demonstration system based on 3D virtual simulation technology was proposed. Starting from the concept of virtual reality (VR), the characteristics of VR and the classification of VR systems were introduced, and the research status of VR technology at home and abroad and the application of 3D virtual simulation were discussed. Then the key technologies of 3D modeling, 3D scene optimization and 3D simulation driving of 3D virtual simulation were expounded, and the characteristics and application scope of different technical methods were analyzed. Finally, an example of the Hongzhou Kiln 3D network museum was listed. Findings The research results showed that 3D virtual simulation has a wide range of applications in the field of VR. Different elements need to be considered for different types of applications, and different contents need to be integrated to achieve the corresponding interaction modes. Originality/value Virtual image; multimedia; large space museum; tourism demonstration system; 3D virtual simulation technology.

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