Non-deterministic 'possibilistic' approaches for structural analysis and optimal design - A comparison of numerical methods for computing structural response uncertainties

1998 ◽  
Author(s):  
Vincent Braibant ◽  
Adrien Oudshoorn ◽  
Chris Boyer ◽  
Franck Delcroix
2020 ◽  
Vol 15 (1) ◽  
pp. 37-44
Author(s):  
El Mehdi Echebba ◽  
Hasnae Boubel ◽  
Oumnia Elmrabet ◽  
Mohamed Rougui

Abstract In this paper, an evaluation was tried for the impact of structural design on structural response. Several situations are foreseen as the possibilities of changing the distribution of the structural elements (sails, columns, etc.), the width of the structure and the number of floors indicates the adapted type of bracing for a given structure by referring only to its Geometric dimensions. This was done by studying the effect of the technical design of the building on the natural frequency of the structure with the study of the influence of the distribution of the structural elements on the seismic response of the building, taking into account of the requirements of the Moroccan earthquake regulations 2000/2011 and using the ANSYS APDL and Robot Structural Analysis software.


2013 ◽  
Vol 785-786 ◽  
pp. 1258-1261
Author(s):  
In Pyo Cha ◽  
Hee Jae Shin ◽  
Neung Gu Lee ◽  
Lee Ku Kwac ◽  
Hong Gun Kim

Topology optimization and shape optimization of structural optimization techniques are applied to transport skate the lightweight. Skate properties by varying the design variables and minimize the maximum stress and strain in the normal operation, while reducing the volume of the objective function of optimal design and Skate the static strength of the constraints that should not degrade compared to the performance of the initial model. The skates were used in this study consists of the main frame, sub frame, roll, pin main frame only structural analysis and optimal design was performed using the finite element method. Simplified initial model set design area and it compared to SM45C, AA7075, CFRP, GFRP was using the topology optimization. Strength does not degrade compared to the initial model, decreased volume while minimizing the stress and strain results, the optimum design was achieved efficient lightweight.


2020 ◽  
Vol 2020.30 (0) ◽  
pp. 2302
Author(s):  
Masataka KAIHARA ◽  
Masato TOI ◽  
Yutaka NOMAGUCHI ◽  
Kikuo FUJITA

2007 ◽  
Vol 34 (9) ◽  
pp. 1069-1074
Author(s):  
Cristhian A. Mancilla Alarcon ◽  
William H McAnally ◽  
Richard L Stockstill

New float-in technology is being applied to construction of floating guard walls in navigation projects such as Olmsted lock and dam on the Ohio River. Guard wall fluid-structure interaction design can be decoupled if the effects of the structural response on the fluid load pattern are negligible. The assumption that the hydrodynamic pressures acting on a floating guard wall can be decoupled from the structural response of the wall is tested. The effects of the flow and pressure distribution in the presence of a typical guard wall were modeled and used as boundary conditions for structural analysis of the guard wall. The deformation of the guard wall was then used to recompute the fluid loads. Because the fluid loading did not change significantly, decoupling is considered to be valid.Key words: hydrodynamic forces, lock guard walls, navigation locks, numerical modeling.


2011 ◽  
Vol 27 (1) ◽  
pp. 129-138 ◽  
Author(s):  
N. Tayşi ◽  
M. T. Göĝüş ◽  
M. Özakça

ABSTRACTIn this paper, the basic finite element formulation of a newly developed family of variable thickness, curved,C(0) continuity Mindlin-Reissner model curved beam elements which include shear deformation and rotatory inertia effects is presented. The accuracy, convergence and efficiency of these newly developed curved beam elements are explored through a series of analyses of arch structures and the results are compared with those obtained by other analytical and numerical methods. The comparisons show that the method yields very good results with a relatively small number of elements.


Author(s):  
C. C. Chamis ◽  
D. A. Hopkins

Development of probabilistic structural analysis methods for hot engine structures is a major activity at Lewis Research Center. It consists of three program elements: (1) composite load spectra methodology, (2) probabilistic structural analysis methodology, and (3) probabilistic structural analysis application. Recent progress includes: (1) quantification of the effects of uncertainties for several variables on High Pressure Fuel Turbopump (HPFT) turbine blade temperature, pressure, and torque of the Space Shuttle Main Engine (SSME), (2) the evaluation of the cumulative distribution function for various structural response variables based on assumed uncertainties in primitive structural variables, and (3) evaluation of the failure probability. Collectively, the results demonstrate that the structural durability of hot engine structural components can be effectively evaluated in a formal probabilistic/reliability framework.


2021 ◽  
Author(s):  
Johyun Kyoung ◽  
Sagar Samaria ◽  
Jeffrey O’Donnell ◽  
Sudhakar Tallavajhula

Abstract Demand for life extension assessments of floating offshore platforms continues to grow worldwide. Conventional structural analysis methods have limited ability to accurately capture non-linear environmental loading, non-linear loading by the mooring and riser systems, and resulting higher order hull responses. The uncertainties are typically managed by the factors of safety applied in the structural analysis. Time domain structural analyses have long promised to improve analysis accuracy and reduce these uncertainties. This paper describes a comprehensive and practical time domain structural analysis methodology applied to a deep-water semi-submersible-type floating platform including results for structural strength and fatigue. In addition, the time domain structural analysis was extended for use in fracture mechanics and the assessment of notional weld flaws to facilitate specification of impactful non-destructive examination (NDE). Present time domain structural analysis methodology employs a response-based finite element analysis (FEA) conducted in the time domain. All external environmental loads and inertial forces are converted to a response-based stress-time history. Previously, conventional time domain structural analysis involves massive computation resources to resolve solutions at every time interval. Present methodology significantly improves computational efficiency to be practical in real-world problems. The improvement is achieved by decomposing the structural response into a set of multiple load components selected on the bases of function for hull motion response and environmental loadings. Structural response in time domain is directly obtained by synthesizing the load components. An actual time domain structural response is captured effectively and efficiently to simulate the strength and fatigue criterion for the structure with consistent environmental loads and hull responses. Utilizing the level of detail provided by the time domain structural analysis methodology, a fracture mechanics evaluation of notional initial flaws (engineering criticality assessments – ECAs) can be conducted providing meaningful technical basis for in-service NDE and life extension assessments. The procedures for fatigue crack growth and fracture documented in BS 7910 were employed to derive the smallest initial flaws (critical initial flaws) that may result in structural failure during a facility's lifetime. A comparison indicates that conventional structural analysis methods provide conservative results for both structural strength and fatigue damage calculations resulting from the linear assumption of environmental loads and hull responses. Present time domain structural analysis methodology provides an innovative, cutting-edge approach providing accuracy and fewer uncertainties, which can be pragmatically used during a typical project.


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