scholarly journals Structural Response Analysis under Dependent Variables Based on Probability Boxes

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Z. Xiao ◽  
G. Yang
Keyword(s):  
Structural Response ◽  
Sampling Strategy ◽  
Optimization Method ◽  
Response Analysis ◽  
Copula Theory ◽  
Lack Of Information ◽  
Dependent Variables ◽  
Random Intervals ◽  
Uncertainty Parameters ◽  
Interval Response

This paper considers structural response analysis when structural uncertainty parameters distribution cannot be specified precisely due to lack of information and there are complex dependencies in the variables. Uncertainties in parameter are quantified by probability boxes (p-boxes) and dependence among uncertain parameters is modeled by copula. To calculate uncertainty structural response, a sampling-based method is proposed. In this method, a sampling strategy is used to sample random intervals from dependentp-boxes according to the copula theory and the metamodel-based optimization method is applied to solve a range of structural interval response problems. Two types of errors are presented to evaluate the error of differentp-boxes. Four numerical examples are investigated to demonstrate the effectiveness of the present method.

Simplified Modeling Research of Reinforced Concrete Based on the Dynamic Stiffness Equivalence

2012 ◽  
Vol 446-449 ◽  
pp. 458-462
Author(s):  
Jie Hu ◽  
Jia Quan Feng ◽  
Xi Nong Zhang
Keyword(s):  
Reinforced Concrete ◽  
Reference Model ◽  
Dynamic Stiffness ◽  
Optimization Method ◽  
Simplified Model ◽  
Response Analysis ◽  
Reinforced Concrete Structure ◽  
Optimization Function ◽  
Nature Frequency ◽  
Simplified Modeling

This paper proposed a simplified modeling method of reinforced concrete based on the equivalence of dynamic stiffness, the parameters of simplified model were modified to make the error of nature frequency between reference model and simplified model as small as possible, and an appropriate optimization function was designed. The essentiality of the proposed method is parameter optimization, with the advantages such as fewer elements and calculation assumption. The numerical simulation result indicated that this optimization method is suitable for the dynamic response analysis of complicated reinforced concrete structure.

Structure Vibration Shape Optimization Based on Power Flow Response Analysis

2014 ◽  
Vol 490-491 ◽  
pp. 712-718
Author(s):  
Xue Bao Xia ◽  
Yang Xiang ◽  
Shao Wei Wu
Keyword(s):  
Shape Optimization ◽  
Mode Shape ◽  
Power Flow ◽  
Flow Analysis ◽  
Optimization Method ◽  
Weight Coefficient ◽  
Surface Shape ◽  
Response Analysis ◽  
Flow Response ◽  
Vibration Power Flow

Power flow analysis is a method to describe the dynamic behavior of structures by taking not only the amplitude of exciting force and velocity response into account, but also the phase between the two qualities. Shape optimization is an effective method to reduce vibration level. By choosing the vibration power flow as design objective, a shape optimization method of structure is presented. The structure surface is restructured with a series of mode shape superposition. By using genetic algorithm, the weight coefficient of each mode shape is optimized to get the best surface shape with minimum power flow response. Some examples are demonstrated to verify the efficiency and accuracy of the method.

Analytical investigation of nonlinear heave-coupled response of tension leg platform

2018 ◽  
Vol 233 (3) ◽  
pp. 699-713
Author(s):  
Mohammad Reza Tabeshpour ◽  
Reza Hedayatpour
Keyword(s):  
Degrees Of Freedom ◽  
Structural Response ◽  
Wave Theory ◽  
Equation Of Motion ◽  
Analytical Investigation ◽  
Response Analysis ◽  
Wave Forces ◽  
Tension Leg Platform ◽  
Heave Motion ◽  
Diffraction Effects

Having deep view in structural response of tension leg platform is important issue not only for response analysis but also for engineering design. Coupling between surge and heave motions of tension leg platform is such a problem. Here, tension leg platform motions are considered only in surge and heave degrees of freedom without pitch effect. The coupled term of heave is a nonlinear differential equation. Because the focus of this article is on this term, therefore, Duffing equation of motion in the surge direction is linearized. The wave forces are calculated using Airy’s wave theory and Morison’s equation, ignoring the diffraction effects. Current force also can be very important in dynamic analysis of tension leg platform. Because it affects the term of heave that is coupled with surge. It is shown that the effect of surge motion coupling on heave motion is very important in large displacement of surge motion in many sea states. The main result is that the coupling effects appeared in some frequencies such as heave and surge frequency, twice the frequency of wave, twice the natural surge frequency, and summation and difference of frequency of wave and surge frequency.

scholarly journals Modified VIKOR method as a component of decision support of information technology of the dual form of education

2021 ◽  
Vol 102 (2) ◽  
pp. 121-129
Author(s):  
Taras Lechachenko ◽  
Olena Karelina
Keyword(s):  
Decision Support ◽  
Educational Institution ◽  
Decision Support Tool ◽  
Optimization Method ◽  
Educational Process ◽  
Vikor Method ◽  
Ranking Problem ◽  
Support Tool ◽  
Lack Of Information ◽  
Proposed Modification

The model for supporting the student decision in choosing the subjects of specialty educational program based on VIKOR multi-criteria optimization method is developed in this paper. The developed model is the component of the dual education information system (when the student is trained in the company and educational institution at the same time on the basis of the contract). This component is a decision support tool for a student training by a dual education, taking into account the expert opinion of stakeholders in the learning process. The criteria of dual education stakeholders for ranking alternatives (subjects of the specialty program): student, educational institution, company are outlined. VIKOR method is modified by the selection of subsystems criteria in order to derive an integrated assessment of experts from different subsystems. The algorithm for integrating ratings of ranking subsystems is developed, taking into account the strategy of maximum group usefulness of VIKOR method. The weighting coefficients of subsystems and their criteria are determined by T. Saati method of hierarchies analysis. In order to take into account the uncertainty associated with the lack of information, intuitionistic fuzzy sets are used to assign assessments of the alternatives ranking by subsystem experts. The proposed modification of VIKOR method makes it possible to rank the alternatives with the involvement of different specialists with their own criteria system. This approach increases the accuracy of the obtained results, as the criteria are further divided into holders subsystems of the ranking problem. This approach enables to carry out deeper and broader analysis of ranking problem aspects. Numerical example of the developed model which confirms the acceptability of its application in practice in the dual educational process application is illustrated in this paper.

scholarly journals Assessment of Structural Performance and Integrity for Vibration-based Energy Harvester in Frequency Domain

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 357
Author(s):  
Ji-Won Jin ◽  
Ki-Weon Kang
Keyword(s):  
Frequency Domain ◽  
Natural Frequency ◽  
Production Efficiency ◽  
Performance Test ◽  
Energy Harvester ◽  
Structural Integrity ◽  
Structural Response ◽  
Structural Performance ◽  
Railway Vehicle ◽  
Response Analysis

A vibration-based energy harvester (VEH) utilizes vibrations originated from various structures and specifically maximizes the displacement of its moving parts, using the resonance between the frequency of external vibration loads from the structure and the natural frequency of VEH to improve power production efficiency. This study presents the procedure to evaluate the structural performance and structural integrity of VEH utilized in a railway vehicle under frequency domain. First of all, a structural performance test was performed to identify the natural frequency and assess the structural response in frequency domain. Then, the static structural analysis was carried out using FE analysis to investigate the failure critical locations (FCLs) and effect of resonance. Finally, we conducted a frequency response analysis to identify the structural response and investigate the structural integrity in frequency domain. Based on these results, the authors assessed the structural performance and integrity of VEHs in two versions.

Numerical Simulation on Fatigue Life Assessment of Free Span for Submarine Pipeline

2015 ◽  
Vol 750 ◽  
pp. 153-159
Author(s):  
Jie Dong ◽  
Xue Dong Chen ◽  
Bing Wang ◽  
Wei He Guan ◽  
Tie Cheng Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fatigue Life ◽  
Oil And Gas ◽  
Structural Response ◽  
Simulation Method ◽  
Life Assessment ◽  
Response Analysis ◽  
Submarine Pipeline ◽  
Fatigue Life Assessment ◽  
Harmonic Response Analysis

The upper and lower courses of sea oil and gas exploitationare connected by submarine pipeline which is called life line project. Free span often occurs because of the unevenness and scour of seabed, and fatigue is one of the main failure modes.In this paper, with the finite element numerical simulation method, based on the harmonic response analysis, the research on the structural response of free span under the vibration induced by vortex was investigated, and the effect of the factors such as flow velocity, length of free span. According to the analysis results,the fatigue life of free span was evaluated.

New Seismic Design Specifications of Highway Bridges in Japan

1994 ◽  
Vol 10 (2) ◽  
pp. 333-356 ◽  
Author(s):  
Kazuhiko Kawashima ◽  
Kinji Hasegawa
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Response ◽  
Seismic Design ◽  
Structural Response ◽  
Highway Bridges ◽  
Lateral Force ◽  
Inertia Force ◽  
Response Analysis ◽  
Design Specifications ◽  
Recent Earthquakes

This paper presents the new seismic design specifications for highway bridges issued by the Ministry of Construction in February 1990. Revisions of the previous specifications were based on the damage characteristics of highway bridges that were developed after the recent earthquakes. The primary revised items include the seismic lateral force, evaluation of inertia force for design of substructures considering structural response, checking the bearing capacity of reinforced concrete piers for lateral load, and dynamic response analysis. Emphasis is placed on the background of the revisions introduced in the new seismic design specifications.

Effects of Empirical Orthogonal Functions in Simplification of Structural Response of a Deep-Water Offshore System Under Current Profile Loading

2020 ◽  
Author(s):  
Michael Binsar Lubis ◽  
Mehrdad Kimiaei ◽  
Hongwei An ◽  
Reza Azarhoush
Keyword(s):  
Deep Water ◽  
Structural Response ◽  
Time History ◽  
Empirical Orthogonal Functions ◽  
Response Analysis ◽  
Good Representation ◽  
Current Profile ◽  
Orthogonal Functions ◽  
Recent Developments ◽  
Guidelines And Standards

Abstract Typical recommended current profiles for marine operations can be found in offshore engineering guidelines and standards. However, for some offshore components (e.g. risers, umbilicals, risers) typical simplified current profiles can easily lead to unrealistic and conservative results. Due to recent developments in current measuring technology, current speed for deep water location can be easily acquired. However, the current speeds are usually recorded for long periods and in many measurement points along the water column. Hence, finding the extreme current profile based on the recorded time-history data is not an easy task since it needs excessive computational efforts. To determine the overall response of an offshore system, various methods have been developed to minimize the required computational efforts in working with big number of irregular current profiles. Mode-based analysis using empirical orthogonal functions is one of these methods. Total number of the utilized modes plays an important role in the numerical complexity of the problem as well as the accuracy of the results. In this study, for a given deep water location, the effects of the reduced number of modes are investigated through response analysis of a simple vertical fixed slender structure under thousands of current profiles. It is found that the reduced-mode profile can produce a good representation of the measured current profile, however it tends to underestimate the structural response.

scholarly journals Structural response analysis of the hydraulic pneumatic tensioner under its local failure based on a fully coupled TLP-TTR system

2020 ◽  
Vol 216 ◽  
pp. 107645
Author(s):  
Shuai Hao ◽  
Yang Yu ◽  
Jianxing Yu ◽  
Zhiming Yuan ◽  
Lixin Xu ◽  
...  
Keyword(s):  
Structural Response ◽  
Local Failure ◽  
Response Analysis ◽  
Fully Coupled
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