scholarly journals A Sensitivity Analysis Approach for Assessing the Effect of Design Parameters in Reducing Seismic Demand of Base-Isolated Storage Racks

2021 ◽  
Vol 11 (23) ◽  
pp. 11553
Author(s):  
Oscar Álvarez ◽  
Enrique Muñoz ◽  
Nelson Maureira-Carsalade ◽  
Ángel Roco-Videla
Keyword(s):  
Sensitivity Analysis ◽  
Structural Engineering ◽  
Structural Parameters ◽  
Response Spectrum ◽  
Shaking Table ◽  
Design Parameters ◽  
Seismic Demand ◽  
Base Shear ◽  
Isolation System ◽  
Storage Racks

The most used global sensitivity analysis (GSA) method is based on variance. This is performed using Monte Carlo Sampling (MCS) or Latin Hypercube Sampling (LHS). It requires a large sample to obtain accurate estimates. Density-based methods, such as the GSA PAWN, have been developed to reduce the sample size without compromising the result. PAWN is simpler than other methods because it uses cumulative density functions (CDF) instead of probability density. This method has been widely used in areas such as environmental engineering with very good results, reducing computation time. However, its use in structural engineering is incipient. The PAWN method was used to classify the design variables of the isolation system in relation to their sensitivity, and in relation to the seismic response of industrial storage racks. The above was analyzed in terms of the effectiveness of each variable to reduce the seismic demand using a novel base isolation kinematic device (BIKD). Racks with different combinations of their structural parameters such as the number of storage levels, the height between them, and isolation period, among others, were studied. The dimensions of the racks were chosen to match those that would later be experimentally tested on shaking table. An earthquake whose response spectrum matched the design spectrum of current Chilean regulations, was considered as seismic forcing. The maximum base shear load, the displacement of the top level of storage and the floor drift were considered as target responses to be studied. Fixed base racks (FBR), as reference, and base-isolated racks (BIR) were analyzed. The results showed the effectiveness of using the BIKD system in reducing all three-target responses up to one order of magnitude. Additionally, it was determined that the parameters that have the greatest influence on the response correspond to the number of storage levels and the height between them, both for FBR and BIR.

Development of a Seismic Isolation System for Commercial Storage Racks

2012 ◽  
Author(s):  
David H. Johnson ◽  
Robert J. Michael ◽  
Michael C. Pollino ◽  
Joseph D. Redovan ◽  
Eric E. Moser ◽  
...  
Keyword(s):  
Structural Damage ◽  
Seismic Isolation ◽  
Structural Engineering ◽  
Base Isolation ◽  
Earthquake Simulation ◽  
Element Analysis ◽  
Isolation System ◽  
Finite Element Analysis Simulation ◽  
Base Isolation System ◽  
Storage Racks

This paper provides an overview of an analysis performed on a new base isolation system developed for seismic isolation of steel pallet storage racks. Pallet storage racks are often found in warehousing for material storage and are designed to store materials on pallets in horizontal rows with multiple levels which are accessed by forklift trucks. The new isolation system provides seismic isolation in the cross-aisle direction by incorporating heavily damped elastomeric bearings (referred to here as seismic mounts) and low-friction bearing plates. The objective of the base isolation system is to reduce horizontal accelerations of the rack to eliminate product shedding and structural damage during a major earthquake without interfering with normal, day-to-day material handling operations. The paper presents a summary of numerical results (transient structural, finite element analysis simulation) comparing storage rack response against actual tests performed on a triaxial shake table in the Structural Engineering and Earthquake Simulation Laboratory (SEESL) at the University at Buffalo (see Filiatrault[1] et al. 2008 for comprehensive test details). The simulation model was then used to determine a set of optimal seismic isolation parameters that satisfy the practical range of rack shelf loads and configurations that can be expected in typical warehouse and store installations.

scholarly journals Potential Design of Seismic Vulnerable Buildings Incorporating Lead Rubber Bearing

Buildings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 37 ◽  
Author(s):  
Walid Al-Kutti ◽  
A. Islam
Keyword(s):  
Structural Damage ◽  
New Technologies ◽  
Structural Parameters ◽  
Response Spectrum ◽  
Base Shear ◽  
Characteristic Strength ◽  
Base Level ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Fixed Base

The seismic hazard of vulnerable regions warrants the investigation of new technologies, such as base level isolation by lead rubber bearing (LRB) devices, that can help to mitigate structural damage on seismic prone buildings. The behavior adopting such technologies can be dynamically observed in simulated environments and thus serves as a valuable metric for their feasibility. LRB base isolators were incorporated into the design of 16 model buildings to better understand how they affected a building’s seismic response while also providing information on the structural parameters. A total of 12 different types of bearing systems were tested in base isolated (BI) buildings against conventional fixed-base (FB) isolated buildings. The system of each model high-rise building was represented by the finite element package. Static as well as dynamic analysis were conducted using response spectrum analysis (RSA) based on the seismic excitation to determine the influence of the model type in the aseismic design and the alteration in superstructure behavior. The study reveals that the LRB isolators can potentially diminish respective story accelerations, story inertia, and base shear. Use of LRB isolators in BI buildings resulted in a 10–20% reduction in base shear compared to FB buildings. A notable lateral shift of superstructure is offered by LRB-induced flexibility. The reduction of story acceleration for response spectrum varies 30% on lower stories up to 70% on upper stories. The LRB systems with higher characteristic strength and relatively less isolation periods shows better productivity to minimize displacements in the bearing face for dropping structural shift. However, the LRB with comparatively lower characteristic strength and high isolation periods shows the most efficiency in controlling base shear, offering least story accelerations and consenting lower story inertia forces.

scholarly journals The Effects of Structural Parameter Variation on Cable Force of Fast Cable-Net Structure

2014 ◽  
Vol 6 ◽  
pp. 912158
Author(s):  
Qiming Wang ◽  
Peng Jiang ◽  
Xu Kong
Keyword(s):  
Sensitivity Analysis ◽  
Global Sensitivity Analysis ◽  
Structural Parameters ◽  
Element Model ◽  
Design Parameters ◽  
Structural Parameter ◽  
Global Sensitivity ◽  
Fatigue Stress ◽  
Cutting Length ◽  
Cable Force

Five-hundred-meter aperture spherical radio telescope (FAST) is supported by a cable-net structure, which enables its surface to form a real-time paraboloid by active control. FAST project is currently in the construction and implementation stage. However, there are always a considerable amount of errors that existed in practice which may result in the deviation of the structure from its ideal model or design. Therefore, structural parameter sensitivity analysis was discussed, which is indispensable. However, such deformation operation would lead to about 500 MPa of fatigue stress variation amplitude in the cable-net structure. Optimized deformation strategy is proposed to release the fatigue stress of the cable-net structure, which would be of advantage to improve the reliability of the cable-net structure. In the paper, the variation ranges of structural parameters were rationally determined. Based on local sensitivity analysis and global sensitivity analysis method, finite element model was used to study the effect of different structural parameters on the static behavior. It can be concluded that the effect of several key design parameters such as the cutting length and the elastic modulus of cable on the cable force is significant. The global sensitivity analysis indicates that the cable force range of the cable-net is −19% to 27%.

Sensitivity Analysis of Beam Cross-Section Stiffness Using Adjoint Method

2017 ◽  
Author(s):  
Alfonso Callejo ◽  
Olivier Bauchau ◽  
Boris Diskin ◽  
Li Wang
Keyword(s):  
Sensitivity Analysis ◽  
Objective Function ◽  
Cross Section ◽  
Structural Parameters ◽  
Flexible Multibody Dynamics ◽  
Numerical Differentiation ◽  
Adjoint Equations ◽  
Design Parameters ◽  
Adjoint Sensitivity ◽  
Cross Sectional

The design optimization of rotorcraft through multidisciplinary aeroelastic models with hundreds of thousands of degrees of freedom requires a computationally efficient sensitivity analysis to obtain the objective function gradient. A fundamental part of rotorcraft analysis is the flexible multibody dynamics solver, which in the current work relies on an accurate three-dimensional representation of the beams. This paper presents the theoretical adjoint sensitivity analysis of the first structural analysis step, namely the computation of cross-sectional properties of the beams in the form of six-dimensional stiffness matrices. The adjoint equations are carefully derived, as are the derivatives of the objective function with respect to the design parameters. The method is then validated by comparing certain design sensitivities of a three-ply, composite cross-section with those obtained through real-step and complex-step numerical differentiation. The presented analysis allows the user to quantify the effect of basic structural parameters on fundamental sectional properties that can later be used in the full dynamic simulation.

Parameter Sensitivity and Reliability Analysis for Construction Control of Cable-Net Structure Supporting the Reflector of FAST

2013 ◽  
Vol 671-674 ◽  
pp. 529-533
Author(s):  
Xu Kong ◽  
Qi Ming Wang ◽  
Chuan Jia Liu ◽  
Zhong Yi Zhu
Keyword(s):  
Sensitivity Analysis ◽  
Global Sensitivity Analysis ◽  
Structural Parameters ◽  
Element Model ◽  
Parameter Sensitivity ◽  
Tension Force ◽  
Design Parameters ◽  
Structural Parameter ◽  
Global Sensitivity ◽  
The Impact

Five-hundred-meter Aperture Spherical radio Telescope (FAST) is supported by cable-net structure, which enables its surface to form a paraboloid in real time under active control. FAST is now entering project construction and implement stage, however there are always a considerable amount of errors existed in practice which would result in the deviation of the structure from its ideal model. Therefore, structural parameter sensitivity analysis was indispensable discussed. In the paper, the variation ranges of structural parameters were rationally determined. Base on local sensitivity analysis and global sensitivity analysis method, Using the finite element model investigated the influence of different structural parameters change on the static behavior, gets the conclusions that the impact of several key design parameters on the tension force of cable-net is large. The results indicate that of all types of the structural parameters, the error of the length of cable plays the most important role, and the global sensitivity analysis indicates that the tension force range of cable-net is -18% to 27%.

scholarly journals CONCEPTUAL DESIGN FOR ASSEMBLY IN AEROSPACE INDUSTRY: SENSITIVITY ANALYSIS OF MATHEMATICAL FRAMEWORK AND DESIGN PARAMETERS

2021 ◽  
Vol 1 ◽  
pp. 731-740
Author(s):  
Giovanni Formentini ◽  
Claudio Favi ◽  
Claude Cuiller ◽  
Pierre-Eric Dereux ◽  
Francois Bouissiere ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Conceptual Design ◽  
Design Parameters ◽  
Design For Assembly ◽  
Mathematical Framework ◽  
Commercial Aircraft ◽  
System Architectures ◽  
Complex Engineering ◽  
Aircraft System ◽  
Definition Of

AbstractOne of the most challenging activity in the engineering design process is the definition of a framework (model and parameters) for the characterization of specific processes such as installation and assembly. Aircraft system architectures are complex structures used to understand relation among elements (modules) inside an aircraft and its evaluation is one of the first activity since the conceptual design. The assessment of aircraft architectures, from the assembly perspective, requires parameter identification as well as the definition of the overall analysis framework (i.e., mathematical models, equations).The paper aims at the analysis of a mathematical framework (structure, equations and parameters) developed to assess the fit for assembly performances of aircraft system architectures by the mean of sensitivity analysis (One-Factor-At-Time method). The sensitivity analysis was performed on a complex engineering framework, i.e. the Conceptual Design for Assembly (CDfA) methodology, which is characterized by level, domains and attributes (parameters). A commercial aircraft cabin system was used as a case study to understand the use of different mathematical operators as well as the way to cluster attributes.

Vulnerability-Based Design of Sliding Concave Bearings for the Seismic Isolation of Steel Storage Tanks

2016 ◽  
Author(s):  
Hoang Nam Phan ◽  
Fabrizio Paolacci ◽  
Silvia Alessandri ◽  
Phuong Hoa Hoang
Keyword(s):  
Liquid Steel ◽  
Seismic Isolation ◽  
Failure Modes ◽  
Fragility Curves ◽  
Time History ◽  
Probability Of Failure ◽  
Design Parameters ◽  
Economic Losses ◽  
Storage Tanks ◽  
Isolation System

Liquid steel storage tanks are strategic structures for industrial facilities and have been widely used both in nuclear and non-nuclear power plants. Typical damage to tanks occurred during past earthquakes such as cracking at the bottom plate, elastic or elastoplastic buckling of the tank wall, failure of the ground anchorage system, and sloshing damage around the roof, etc. Due to their potential and substantial economic losses as well as environmental hazards, implementations of seismic isolation and energy dissipation systems have been recently extended to liquid storage tanks. Although the benefits of seismic isolation systems have been well known in reducing seismic demands of tanks; however, these benefits have been rarely investigated in literature in terms of reduction in the probability of failure. In this paper, A vulnerability-based design approach of a sliding concave bearing system for an existing elevated liquid steel storage tank is presented by evaluating the probability of exceeding specific limit states. Firstly, nonlinear time history analyses of a three-dimensional stick model for the examined case study are performed using a set of ground motion records. Fragility curves of different failure modes of the tank are then obtained by the well-known cloud method. In the following, a seismic isolation system based on concave sliding bearings is proposed. The effectiveness of the isolation system in mitigating the seismic response of the tank is investigated by means of fragility curves. Finally, an optimization of design parameters for sliding concave bearings is determined based on the reduction of the tank vulnerability or the probability of failure.

Measured natural periods of concrete shear wall buildings: insights for the design of Canadian buildings

2012 ◽  
Vol 39 (8) ◽  
pp. 867-877 ◽  
Author(s):  
Damien Gilles ◽  
Ghyslaine McClure
Keyword(s):  
Seismic Analysis ◽  
Dynamic Properties ◽  
Response Spectrum ◽  
Shear Wall ◽  
Mode Shapes ◽  
Design Stage ◽  
Base Shear ◽  
Period Equation ◽  
Input Load ◽  
Structural Engineers

Structural engineers routinely use rational dynamic analysis methods for the seismic analysis of buildings. In linear analysis based on modal superposition or response spectrum approaches, the overall response of a structure (for instance, base shear or inter-storey drift) is obtained by combining the responses in several vibration modes. These modal responses depend on the input load, but also on the dynamic characteristics of the building, such as its natural periods, mode shapes, and damping. At the design stage, engineers can only predict the natural periods using eigenvalue analysis of structural models or empirical equations provided in building codes. However, once a building is constructed, it is possible to measure more precisely its dynamic properties using a variety of in situ dynamic tests. In this paper, we use ambient motions recorded in 27 reinforced concrete shear wall (RCSW) buildings in Montréal to examine how various empirical models to predict the natural periods of RCSW buildings compare to the periods measured in actual buildings under ambient loading conditions. We show that a model in which the fundamental period of RCSW buildings varies linearly with building height would be a significant improvement over the period equation proposed in the 2010 National Building Code of Canada. Models to predict the natural periods of the first two torsion modes and second sway modes are also presented, along with their uncertainty.

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