Three-Stage Multiscale Nonlinear Dynamic Analysis Platform for Building-Level Loss Estimation

2015 ◽  
Vol 31 (2) ◽  
pp. 1021-1042 ◽  
Author(s):  
In Ho Cho ◽  
Keith Porter
Keyword(s):  
Dynamic Analysis ◽  
Information Transfer ◽  
Large Scale ◽  
Nonlinear Dynamic Analysis ◽  
Loss Estimation ◽  
Element Analysis ◽  
Global Dynamic ◽  
Micro Level ◽  
Analysis Platform ◽  
Vulnerability Functions

Large-scale loss estimation needs vulnerability functions that relate ground motion to repair cost for each of many building classes. A challenge to generating analytical vulnerability functions for a building class is that one needs to reflect seismic performance at several scales, from the size of cracks to the whole building. Here, we propose a three-stage multiscale platform tackling a general reinforced concrete (RC) building containing complex walls: (1) at the micro level, a microphysical mechanism-based parallel finite element analysis (FEA) engine captures microscopic nonlinearities; (2) the macro level handles computationally expensive dynamic analyses of buildings; (3) the meso level manages interscale information transfer and describes floor-specific variability. Multiple parallel FEA engines run in concert with a stand-alone dynamic analysis platform. Importantly, the micro level resolves damage phenomena explicitly—no fragility inference is required—propagating component damage to global dynamic analysis. Now, one can link microscopic damage to building seismic loss.

A Nonlinear Dynamic Substructuring Approach to Global Dynamics of Flexible Riser Systems

2014 ◽  
Author(s):  
Arya Majed ◽  
Phil Cooper
Keyword(s):  
Dynamic Analysis ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Nonlinear Effects ◽  
Global Dynamics ◽  
Computationally Efficient ◽  
Flexible Riser ◽  
Dynamic Simulations ◽  
Stick Slip ◽  
Global Dynamic

Standard riser global dynamic analysis software packages utilize line element models that cannot capture the complex behavior of flexible risers. This paper presents a computationally efficient nonlinear dynamic analysis methodology capable of incorporating detailed finite element models and scalable to global dynamic simulations of entire flexible riser systems. Subject methodology captures the global geometric nonlinear effects and its coupling to stick-slip friction — a clear requirement for accurate armour stress predictions. In addition, the method enables the formulation of stress transformation matrices which allow the direct recovery of armour stresses from the global simulations. A demonstration problem involving the nonlinear dynamic simulation of a 500m flexible riser system is presented.

The Finite Element Analysis and Comparison of Wind Turbine Tower under Static Wind Load and Fluctuating Wind Load

2013 ◽  
Vol 446-447 ◽  
pp. 733-737
Author(s):  
Chi Chen ◽  
Hao Yuan Chen ◽  
Tian Lu
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Wind Turbine ◽  
Modal Analysis ◽  
Large Scale ◽  
Wind Load ◽  
Element Analysis ◽  
Finite Element Software ◽  
Wind Turbine Tower ◽  
Fluctuating Wind

In this paper, a 1.5 MW wind turbine tower in Dali, Yunnan Province is used as the research object, using large-scale finite element software Ansys to carry on the dynamic analysis. These natural frequencies and natural vibration type of the first five of tower are obtained by modal analysis and are compared with natural frequency to determine whether the resonance occurs. Based on the modal analysis, the results of the transient dynamic analysis are obtained from the tower, which is loaded by the static wind load and fluctuating wind load in two different forms. By comparing the different results, it provides the basis for the dynamic design of wind turbine tower.

Nonlinear Dynamic Analysis of an Icosahedron Frame which Exhibits Chaotic Behavior

2016 ◽  
Vol 12 (1) ◽  
Author(s):  
Lucas W. Just ◽  
Anthony M. DeLuca ◽  
Anthony N. Palazotto
Keyword(s):  
Dynamic Response ◽  
Boundary Conditions ◽  
Dynamic Analysis ◽  
Chaotic Behavior ◽  
Research Question ◽  
Nonlinear Dynamic Analysis ◽  
Surface Force ◽  
Element Analysis ◽  
Point Distribution ◽  
Chaotic Response

The research question addressed is whether a lighter than air vehicle (LTAV), which uses an internal vacuum to become positively buoyant, can be designed to provide extended loiter for U.S. Air Force applications. To achieve a vacuum, internal gases are evacuated from the vessel, which creates a dynamic response in the supporting structural frame. This paper considers the frame of an icosahedron shaped LTAV subject to external atmospheric pressure evacuated at varying rates. A static finite element analysis documented in previous research revealed a snapback phenomenon in the frame members under certain loading conditions. A nonlinear chaotic response was observed when a dynamic analysis was conducted with the same boundary conditions used in the static analysis. The chaotic response for a variety of boundary conditions, generated by varying the rate of evacuation, similar to a ramp input, is determined. An analysis of the dynamic response is determined nonlinearly using a method that relies on a reference point distribution of external pressures to distribute the surface force across the frame. A novel method of combining the power spectral density with a Lyapunov exponent was used to determine the degree of nonlinearity and chaotic response for each boundary condition examined.

Dynamics of Flexible Mechanical Systems Using Vibration and Static Correction Modes

1986 ◽  
Vol 108 (3) ◽  
pp. 315-322 ◽  
Author(s):  
W. S. Yoo ◽  
E. J. Haug
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Elastic Deformation ◽  
Large Scale ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Nonlinear Dynamic Analysis ◽  
Mode Analysis ◽  
Lumped Mass ◽  
Static Correction

A finite-element-based method is developed and applied for geometrically nonlinear dynamic analysis of spatial mechanical systems. Vibration and static correction modes are used to account for linear elastic deformation of components. Boundary conditions for vibration and static correction mode analysis are defined by kinematic constraints between components of a system. Constraint equations between flexible bodies are derived and a Lagrange multiplier formulation is used to generate the coupled large displacement-small deformation equations of motion. A standard, lumped mass finite-element structural analysis code is used to generate deformation modes and deformable body mass and stiffness information. An intermediate-processor is used to calculate time-independent terms in the equations of motion and to generate input data for a large-scale dynamic analysis code that includes coupled effects of geometric nonlinearity and elastic deformation. Two examples are presented and the effects of deformation mode selection on dynamic prediction are analyzed.

Inelastic Dynamic Analysis of Steel Structure Using Force Analogy Method

2012 ◽  
Vol 166-169 ◽  
pp. 304-309 ◽  
Author(s):  
Shi Qiang Song ◽  
Gang Li
Keyword(s):  
Dynamic Analysis ◽  
Plastic Hinge ◽  
Nonlinear Dynamic Analysis ◽  
Steel Structure ◽  
Response Analysis ◽  
Analysis Method ◽  
Element Analysis ◽  
Analogy Method ◽  
Traditional Algorithm ◽  
Response State

Force analogy method is a kind of nonlinear dynamic analysis method. Analyzing inelastic structural behavior by using plastic hinge theory, it is widely appropriate to many structures with different material properties and very time efficient and numerically accurate without complicated iterative computations in traditional algorithm. Compared with the traditional finite-element analysis method, dynamic response analysis based on force analogy method has obvious advantages. The application of force analogy method to a steel structure is presented and the analysis result shows that the method algorithm can represent each response state of the structure in real-time and has the very good accuracy and practical.

Multiscale Finite Element Analysis of Unbonded Flexible Risers

2014 ◽  
Author(s):  
Ben Edmans ◽  
Dinh Chi Pham ◽  
Zhiqian Zhang ◽  
Tianfu Guo ◽  
Sridhar Narayanaswamy ◽  
...  
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Dynamic Analysis ◽  
Large Scale ◽  
Failure Modes ◽  
Life Extension ◽  
Equivalent Material ◽  
Analysis Model ◽  
Element Analysis ◽  
Flexible Risers

Unbonded flexible risers are a key technology in existing and proposed offshore developments. With increasing water depth, the demands on risers increase and the design against hydrostatic and tension loads becomes more of a challenge. In addition, many existing subsea production systems are approaching the end of their design life and operators need to know if they can remain in-service. To enable the benefits from deepwater production and life extension projects to be realized while minimizing risks to life, property and the environment, accurate modelling and analysis tools are required to improve the prediction of failure modes and to develop a better understanding of the conditions leading to progressive failure. In this work, a multi-scale approach is adopted whereby a global dynamic analysis model is employed to determine the overall displacements of the riser and this is linked with a local model that can provide accurate forces and stresses for the prediction of collapse, fatigue damage and buckling of tensile armour wires. Firstly, we describe a nonlinear constitutive model for use in large-scale dynamic analysis of flexible risers based on an analytical homogenization of composite cylinders using the analogy between slip between pipe layers and plastic flow in continua. The model is able to reproduce the bending hysteresis behaviour observed in flexible pipes and its dependence on internal and external pressure. Secondly, we show a procedure for obtaining equivalent material parameters for this model from finite element local analyses of a flexible pipe. Finally, we show the implementation of this constitutive model in a riser system using two-dimensional co-rotational hybrid beam finite elements.

Comportement dynamique des lignes aériennes de transport d'électricité dû aux bris de câbles. I. Modélisation mathématique

1989 ◽  
Vol 16 (3) ◽  
pp. 335-353 ◽  
Author(s):  
Ghyslaine McClure ◽  
René Tinawi
Keyword(s):  
Mathematical Model ◽  
Dynamic Analysis ◽  
Transmission Lines ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Physical Models ◽  
Element Analysis ◽  
Electric Transmission ◽  
Electric Transmission Lines ◽  
Supporting Structures

This paper presents a mathematical model for the nonlinear dynamic analysis of aerial electric transmission lines subjected to conductor breakage. The model uses existing finite elements and validated numerical techniques available in most commercial programs capable of handling nonlinear dynamic analysis. ADINA is used in this study. In comparison with other models, the novel approach presented here focusses on the discretization of the conductors as well as the supporting structures, specially near the breakage point. Dynamic interactions between all the structural components are therefore considered and comparisons with simpler models emphasize the importance of these interactions, the effects of geometric nonlinearities present in the conductors and in the supporting structures, and the contribution of higher modes.The mathematical model is validated with 7 of 56 tests conducted on reduced-scale physical models, reported in work done for the American Electric Power Research Institute.The results of the present study are very encouraging for designers interested in validating their design criteria for longitudinal dynamic loads by use of existing nonlinear dynamic finite element analysis packages. Key words: Nonlinear dynamic analysis, electric transmission lines, conductor breakage simulation.

scholarly journals Insights gained from constructing a large scale dynamic analysis platform

2017 ◽  
Vol 22 ◽  
pp. S48-S56 ◽  
Author(s):  
Cody Miller ◽  
Dae Glendowne ◽  
Henry Cook ◽  
DeMarcus Thomas ◽  
Chris Lanclos ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
Large Scale ◽  
Analysis Platform

Flexible Riser Bending Hysteresis Influence on Bend Stiffener Response

2014 ◽  
Author(s):  
Marcelo Caire
Keyword(s):  
Dynamic Analysis ◽  
Segment Length ◽  
Analysis Tool ◽  
Flexible Riser ◽  
Element Analysis ◽  
Irregular Wave ◽  
Global Dynamic ◽  
Flexible Risers ◽  
Curvature Distribution ◽  
Internal Pressures

The bending stiffness response is an important parameter in the lifetime assessment of unbounded flexible risers. Its behavior is governed by interlayer friction mechanisms leading to a non-linear moment x curvature relationship that is highly dependent on the internal pressure. In order to investigate its influence on the critical bend stiffener hang-off region response, a detailed finite element analysis is carried out using a specialized tool for a short segment length of a selected 2.5″ ID riser cross section. Different internal pressures are numerically analyzed and the resulting local hysteretic bending response is then adjusted and directly incorporated into a global dynamic analysis tool that uses an equivalent elasto-plastic formulation with a hardening parameter that controls the behavior of the slippage mechanism. A fully coupled irregular wave dynamic analysis is then carried out and the flexible riser curvature distribution response in the bend stiffener region compared for different bending hysteresis models adopted.

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