Effect of buckling-restrained brace model parameters on seismic structural response

2014 ◽  
Vol 98 ◽  
pp. 100-113 ◽  
Author(s):  
Quan Gu ◽  
Alessandro Zona ◽  
Yi Peng ◽  
Andrea Dall'Asta
Keyword(s):  
Structural Response ◽  
Model Parameters ◽  
Buckling Restrained Brace

Simulating and analyzing artificial nonstationary earthquake ground motions

1982 ◽  
Vol 72 (2) ◽  
pp. 615-636
Author(s):  
Robert F. Nau ◽  
Robert M. Oliver ◽  
Karl S. Pister
Keyword(s):  
Difference Equations ◽  
Kalman Filters ◽  
Ground Motions ◽  
Structural Response ◽  
Model Parameters ◽  
Time Varying ◽  
Nonparametric Method ◽  
Linear Difference Equations ◽  
Earthquake Ground Motions ◽  
Earthquake Accelerograms

Abstract This paper describes models used to simulate earthquake accelerograms and analyses of these artificial accelerogram records for use in structural response studies. The artificial accelerogram records are generated by a class of linear linear difference equations which have been previously identified as suitable for describing ground motions. The major contributions of the paper are the use of Kalman filters for estimating time-varying model parameters, and the development of an effective nonparametric method for estimating the variance envelopes of the accelerogram records.

scholarly journals A Parametric Study of Jointed Plain Concrete Pavement Using Finite Element Modeling

2017 ◽  
Vol 11 (11) ◽  
pp. 75
Author(s):  
Monireh Zokaei ◽  
Mansour Fakhri ◽  
Saeed Rahiminezhad
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Thermal Stresses ◽  
Structural Response ◽  
Plain Concrete ◽  
Concrete Pavement ◽  
Model Parameters ◽  
3D Fem ◽  
Element Modeling ◽  
Axle Loads

Concrete pavements face various types of distresses such as longitudinal, transverse, and joint cracking due to traffic loading and thermal stresses. The objective of this investigation was to develop Three-Dimensional Finite-Element Models (3D-FEM) to assess the performance of dowel in Jointed Plain Concrete Pavement (JPCP).Finite-element modeling is a powerful tool that can be used for the simulation of the structural response of pavements under the effects of different loading condition. Most of the previous studies ignored important factors, including the combined effect of dynamic axle loads and thermal gradient. Overcoming the shortcomings of the previous studies, this study investigated the pavement response under the effect of some model parameters. The result of the study was verified by a comparison with field measurements. Results also showed that the combined negative gradient and axle loads located at the transverse joint subject the top of mid-slab, to high tensile stress that may explain the initiation of top-down cracks. These stresses increase under corner loading when the slab length is increased. In general, the study presented that the developed 3D-FEM is suitable for identifying the effect of different design features including pavement geometry, material properties, thermal gradients, and axle load and configuration on the structural response of rigid pavements.

scholarly journals Performance of the Cold-Bending Channel-Angle Buckling-Restrained Brace under Cyclic Loading

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Kun Wang ◽  
Junwu Xia ◽  
Xiaomiao Chen ◽  
Bo Xu ◽  
Xiangzhou Liang ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Model Parameters ◽  
Loading Test ◽  
Skeleton Curve ◽  
Channel Angle ◽  
Buckling Restrained Brace ◽  
External Constraint ◽  
Cold Bending ◽  
Hysteretic Performance

In this study, three restricted cold-bending channel-angle buckling-restrained brace (CCA-BRB) specimens were experimentally characterised by a low-reversed cyclic loading test. Three specimens had steel cores with cruciform cross section. Two restraining units were assembled to form an external constraint member, each of which was composed of an equilateral cold-bending channel and two equilateral cold-bending angles via welding. A gap or a thin silica gel plate was set between the internal core and the external constraint member to form an unbonded layer. Several evaluation parameters on the seismic performance, hysteretic behaviour, and energy dissipation capability of the CCA-BRB was investigated, including hysteresis curve, skeleton curve, compression strength adjustment factor, measured and computed stiffness, energy dissipation coefficient, equivalent viscous damping ratio, ductility coefficient, and cumulative plastic deformation. The test results and evaluation indices demonstrated that the hysteretic performance of braces with a rigid connection was stable. A Ramberg–Osgood model and two model parameters were calibrated to predict, with fidelity, the skeleton curve of CCA-BRB under cyclic load. The initial elastic stiffness of the brace used in practice should contain overall portions of the brace instead of the yielding portion of the brace. Finally, all the tested CCA-BRBs exhibited a stable energy absorption performance and verified the specimens’ construction was rational.

scholarly journals Tensile Bending Stresses in Mortar-Grouted Riprap Revetments Due to Wave Loading

2020 ◽  
Vol 8 (11) ◽  
pp. 913
Author(s):  
Moritz Kreyenschulte ◽  
Holger Schüttrumpf
Keyword(s):  
Structural Response ◽  
Model Tests ◽  
Model Parameters ◽  
Sound Design ◽  
Wave Loading ◽  
Technical Standards ◽  
Bending Stresses ◽  
Porosity And Permeability ◽  
Standards And Guidelines ◽  
Dynamic Wave

One of the most common revetment types in Germany is the mortar-grouted riprap revetment (MGRR), which is constructed by placing riprap on a filter or separation layer and subsequent grouting with mortar. Existing technical standards and guidelines for MGRRs do not consider the interaction between dynamic wave loading and structural response. To date, scientifically sound design approaches verified by model tests are missing. Therefore, the aim of this work is to establish a process-based model for the calculation of the acting bending tensile stresses during wave attack for MGRRs to asses crack formation. To this end, MGRRs were modelled as plates on an elastic foundation (PEF). Hydraulic boundary conditions were determined with full-scale hydraulic model tests. Model parameters of the PEF model were established by investigations into the mechanical parameters of the constituents of MGRRs. The results show that tensile bending stresses are particularly dependent on the pressure difference between the top and bottom edge of the top layer, which varies significantly for MGRRs as their porosity and permeability varies significantly depending on the amount of mortar used for grouting. Enveloping functions for maximum relative tensile bending stress σx,max/(ρwgHm0) are given for four configurations of MGRRs that are of great practical relevance.

scholarly journals Structural Response of a Reciprocating Compressor's Discharge Tube Subjected to Model and Data Uncertainties

2018 ◽  
Vol 23 (No 3, September 2018) ◽  
pp. 385-391
Author(s):  
Filipe Fontanela ◽  
Olavo Mecias da Silva ◽  
Thiago Antonio Fiorentin ◽  
Arcanjo Lenzi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stochastic Models ◽  
Structural Response ◽  
Model Parameters ◽  
Manufacturing Processes ◽  
The Finite Element Method ◽  
Physical Processes ◽  
Parameter Uncertainties ◽  
Deterministic Framework

The analysis of the dynamical responses of compressor components are typically evaluated by using mathematicalmechanical models, and many decisions are given based on numerical simulations. Such an investigation is usually performed in a deterministic framework that cannot consider the uncertainties of the numerical model. These uncertainties are present in a numerical investigation due to the variability of the model parameters, caused by the limitations of the manufacturing processes, as well as simplifications and/or lack of knowledge to describe complex physical processes accurately. In order to quantify the sensitivity of the model parameters and the epistemic uncertainties of a discharge tube’s structural numerical response—solved by the finite element method—two stochastic models are constructed, and their results are simultaneously analysed. The dynamical responses obtained from both stochastic models identify the robustness limits of the structural response when it is subjected to parameter uncertainties as well as model sensitivity by separating each contribution in the estimated dynamical structural response.

scholarly journals Identifying a Minimal Rheological Configuration: A Tool for Effective and Efficient Constitutive Modeling of Soft Tissues

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Petr Jordan ◽  
Amy E. Kerdok ◽  
Robert D. Howe ◽  
Simona Socrate
Keyword(s):  
Soft Tissues ◽  
Ex Vivo ◽  
Constant Strain Rate ◽  
Structural Response ◽  
Biological Tissues ◽  
Tissue Response ◽  
Model Parameters ◽  
Modeling Framework ◽  
Porcine Liver ◽  
Constitutive Relationships

We describe a modeling methodology intended as a preliminary step in the identification of appropriate constitutive frameworks for the time-dependent response of biological tissues. The modeling approach comprises a customizable rheological network of viscous and elastic elements governed by user-defined 1D constitutive relationships. The model parameters are identified by iterative nonlinear optimization, minimizing the error between experimental and model-predicted structural (load-displacement) tissue response under a specific mode of deformation. We demonstrate the use of this methodology by determining the minimal rheological arrangement, constitutive relationships, and model parameters for the structural response of various soft tissues, including ex vivo perfused porcine liver in indentation, ex vivo porcine brain cortical tissue in indentation, and ex vivo human cervical tissue in unconfined compression. Our results indicate that the identified rheological configurations provide good agreement with experimental data, including multiple constant strain rate load/unload tests and stress relaxation tests. Our experience suggests that the described modeling framework is an efficient tool for exploring a wide array of constitutive relationships and rheological arrangements, which can subsequently serve as a basis for 3D constitutive model development and finite-element implementations. The proposed approach can also be employed as a self-contained tool to obtain simplified 1D phenomenological models of the structural response of biological tissue to single-axis manipulations for applications in haptic technologies.

scholarly journals PREDICTION OF HIGH-PERFORMANCE FIBERREINFORCED POLYMER CONCRETE USING FUZZY NEURAL NETWORK PROTOTYPES

YMER Digital ◽  
2022 ◽  
Vol 21 (01) ◽  
pp. 192-205
Author(s):  
N Raghuraman ◽  
Keyword(s):  
Neural Network ◽  
High Performance ◽  
Fuzzy Neural Network ◽  
Structural Response ◽  
Polymer Concrete ◽  
Model Parameters ◽  
Maintenance Time ◽  
Fuzzy Neural ◽  
Rc Building

RC building elements of Reinforcing and upgrading is essential to extend its maintenance time, to overcome first structural limitations, and to control the consequence of building construction or design flaws. The RC constructions are reinforced by using the FRP-fiber reinforced polymer. This study utilizes the FRP in concrete structures for instance a Jute, coir, and Sisal is explored for its reliability in improving ductility and strength related structural performance. FRP structural response of the model parameters is studied by measuring the numerical and experimental terms, for instance, Ductility, Deflection, Tensile-Strength, and Compression-Strength. The quality of the sample specimens is tested by using the Fuzzy Neural Network (FNN) system. At this time, compared with existing jobs, the propounded Fuzzy Neural Network model accomplishes the best presentation regarding all boundaries for the fiberreinforced specimen over different stacked conditions

MODELING AND CALIBRATION OF UNCERTAINTY IN MATERIAL PROPERTIES OF ADDITIVELY MANUFACTURED COMPOSITES

2021 ◽  
Author(s):  
EMIL PITZ ◽  
SEAN ROONEY ◽  
KISHORE POCHIRAJU
Keyword(s):  
Neural Networks ◽  
Structural Response ◽  
Correlation Coefficients ◽  
Optimization Methods ◽  
Strength Distribution ◽  
Rotation Parameter ◽  
Image Correlation ◽  
Model Parameters ◽  
Strain Fields ◽  
Correlation Lengths

Simulations quantifying the uncertainty in structural response and damage evolution require accurate representation of the randomness of the underlying material stiffness and strength behaviors. In this paper, the mean and variance descriptions of variability of strength and stiffness of additively manufactured composite specimens are augmented with random field correlation descriptors that represent the process dependence on the property heterogeneity through microstructure variations. Two correlation lengths and a rotation parameter are introduced into randomized stiffness and strength distribution fields to capture the local heterogeneities in the microstructure of Additively Manufactured (AM) composites. We formulated a simulation and Artificial Intelligence (AI)-based technique to calibrate the correlation length and rotation parameter measures from relatively few samples of experimentally obtained strain field observations using Digital Image Correlation (DIC). The neural networks used for calibrating the correlation lengths of Karhunen-Loève Expansion (KL expansion) from the DIC images are trained using simulated stiffness and strength fields that have known correlation coefficients. A virtual DIC filter is used to add the noise and artifacts from typical DIC analysis to the simulated strain fields. A Deep Neural Network (DNN), whose architecture is optimized using Efficient Neural Architecture Search (ENAS), is trained on 150,000 simulated DIC images. The trained DNN is then used for calibration of KL expansion correlation lengths for additively manufactured composite specimens. The AM composites are loaded in tension and DIC images of the strain fields are generated and presented to the DNNs, which produce the correlation coefficients for the random fields as outputs. Compared to classical optimization methods to calibrate model parameters iteratively, neural networks, once trained, efficiently and quickly predict parameters without the need for a robust simulator and optimization methods.

Nonlinear Finite Element Analysis of Pipe Bends Subjected to Inplane Bending

2016 ◽  
Author(s):  
Venkata M. K. Akula ◽  
David W. Martin
Keyword(s):  
Finite Element ◽  
Structural Integrity ◽  
Three Dimensional ◽  
Structural Response ◽  
Sensitivity Analyses ◽  
Model Parameters ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Shell Elements ◽  
Length Changes

Pipe bends are structural components that provide flexibility to accommodate length changes in pipelines while allowing fluid flow. Estimating the collapse load is critical to ensuring the structural integrity of the pipeline. This research discusses modeling and analysis of pipe bends utilizing the finite element method. Three-dimensional models utilizing elbow elements, shell elements, and brick elements are generated to predict the collapse moment of pipe bends subjected to in-plane loading. All simulation was performed using Abaqus. To obtain a more physically-consistent response, material, geometric, and boundary nonlinearities are all included. A MPC user subroutine is utilized to capture the end behavior of the pipe bends correctly when utilizing shell and brick elements. Experimental data from two sources, available in literature, was used to evaluate the effect of the different element types on the predicted structural response. Finally, utilizing the shell, brick, and the elbow elements, parameter sensitivity analyses are performed to identify the key parameters influencing the response of pipe bends. Multiple parameters are varied independently of each other to fully understand and capture their influence on the response. SIMULIA’s Isight software was used to automate the workflow and vary the model parameters about their respective baseline values.

Instrumental and Ideological Union Commitment: Longitudinal Assessment of Construct Validity

2001 ◽  
Vol 17 (2) ◽  
pp. 98-111 ◽  
Author(s):  
Anders Sjöberg ◽  
Magnus Sverke
Keyword(s):  
Construct Validity ◽  
Temporal Stability ◽  
Strong Support ◽  
Internal Consistency Reliability ◽  
Measurement Model ◽  
Two Dimensions ◽  
Model Parameters ◽  
Longitudinal Assessment ◽  
Union Commitment ◽  
Union Participation

Summary: Previous research has identified instrumentality and ideology as important aspects of member attachment to labor unions. The present study evaluated the construct validity of a scale designed to reflect the two dimensions of instrumental and ideological union commitment using a sample of 1170 Swedish blue-collar union members. Longitudinal data were used to test seven propositions referring to the dimensionality, internal consistency reliability, and temporal stability of the scale as well as postulated group differences in union participation to which the scale should be sensitive. Support for the hypothesized factor structure of the scale and for adequate reliabilities of the dimensions was obtained and was also replicated 18 months later. Tests for equality of measurement model parameters and test-retest correlations indicated support for the temporal stability of the scale. In addition, the results were consistent with most of the predicted differences between groups characterized by different patterns of change/stability in union participation status. The study provides strong support for the construct validity of the scale and indicates that it can be used in future theory testing on instrumental and ideological union commitment.

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