A load space formulation for probabilistic finite element analysis of structural reliability

1999 ◽  
Vol 14 (1-2) ◽  
pp. 73-81 ◽  
Author(s):  
X.L. Guan ◽  
R.E. Melchers
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Reliability ◽  
Element Analysis ◽  
Space Formulation

scholarly journals Research on Bridge Structure Reliability Evaluation due to Vessels Collison Based on a Statistical Moment Method

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Tao Fu ◽  
Yang Liu ◽  
Zhixin Zhu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Moment Method ◽  
Structural Reliability ◽  
Statistical Moment ◽  
Bridge Structure ◽  
Element Analysis ◽  
Performance Function ◽  
Structural Resistance ◽  
Collision Force

Damage to bridge structures caused by vessel collision is a risk for bridges crossing water traffic routes. Therefore, safety around vessel collision of existing and planned bridges is one of the key technical problems that must be solved by engineering technicians and bridge managers. In the evaluation of the reliability of the bridge structure, the two aspects of vessel-bridge collision force and structural resistance need to be considered. As there are many influencing parameters, the performance function is difficult to express by explicit function. This paper combines the moment method theory of structural reliability with finite element analysis and proposes a statistical moment method based on finite element analysis for the calculation of vessel-bridge collision reliability, which solves the structural reliability problem with a nonlinear implicit performance function. According to the probability model based on current velocity, vessel velocity, and vessel collision tonnage, the estimate points in the standard normal space are converted into estimate points in the original state space through the Rosenblatt reverse transform. According to the estimate points in the original state space and the simplified dynamic load model of vessel-bridge collision, the sample time-history curve of random vessel-bridge collision force is generated, the dynamic response of the bridge structure and the structural resistance of the bridge are calculated by establishing a finite element model, and the failure probability and reliability index of the bridge structure is calculated according to the fourth-moment method. The statistical moment based on the finite element analysis is based on the finite element analysis and the moment method theory of structural reliability. The statistical moment of the limited performance function is calculated through a quite small amount of confirmatory finite element analysis, and the structural reliability index and failure probability are obtained. The method can be widely used in existing finite element analysis programs, greatly reducing the number of finite element analyses needed and improving the efficiency of structural reliability analysis.

Finite Element Analysis on Stellite 17mm Tube Valve for Pediatric Ventricular Assist Device

2017 ◽  
Author(s):  
Christopher M. Scheib ◽  
Raymond K. Newswanger ◽  
Allison M. Beese ◽  
Timothy Bowen ◽  
Gregory S. Lewis ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Ventricular Assist Device ◽  
Structural Reliability ◽  
Cobalt Chromium ◽  
Assist Device ◽  
Element Analysis ◽  
Ventricular Assist ◽  
Material Choice

A Stellite 25 17mm tube valve based upon the Björk-Shiley Monostrut (BSM) valve design was developed for use in the Penn State Pediatric Ventricular Assist Device (PVAD) pump [1]. The hook of the valve was designed to hold a Delrin occluding disc in place while allowing the disc to tilt open 70 degrees from the closed position. Unlike common design constraints which remain in the elastic region, the hook experiences plastic deformation twice during the assembly process, making the material choice of Stellite 25 imperative. Stellite 25 is a cobalt-chromium-tungsten-nickel alloy (Co-20Cr-15W-10Ni) belonging to the material family of superalloys which are commonly used for wear-resistant applications exposed to heat, abrasion, and galling [2, 3]. Along with its excellent in vivo corrosion resistance [4], Stellite 25 exhibits high strength and ductility which permit the hook to be plastically deformed during disc installation while remaining below the strain to failure [3, 4]. Together these qualities make Stellite 25 an ideal material choice for the 17mm tube valve application. Predicting the resultant stresses and strains is critical for determining the safety and structural reliability of the Stellite 25 17mm tube valve for the PVAD after assembly. After performing finite element analysis (FEA), the simulation results were validated by deflection experiments and metallurgical investigations.

An Analytical Contact Model for Design of Compliant Fingers

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Chao-Chieh Lan ◽  
Kok-Meng Lee
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Reliability ◽  
Contact Problems ◽  
Contact Forces ◽  
Constrained Minimization ◽  
The Other ◽  
One Dimension ◽  
Shear Deformations ◽  
Element Analysis

A compliant gripper gains its dextral manipulation by the flexural motion of its fingers. It is a preferable device as compared to grippers with multijoint actuations because of reduced fabrication complexity and increased structural reliability. The prediction of contact forces and deflected shape are essential to the design of a compliant finger. A formulation based on nonlinear constrained minimization is presented to analyze contact problems of compliant fingers. The deflections by flexural and shear deformations are both considered. For a planar finger, this formulation further reduces the domain of discretization by one dimension. Hence, it offers a simpler formulation and is computationally more efficient than other methods such as finite element analysis. This method is rather generic and can facilitate design analysis and optimization of compliant fingers. We illustrate some of these attractive features with two types of compliant fingers, one for object handling and the other for snap-fit assembly applications.

Strain Space Formulation of the Armstrong-Frederick Family of Plasticity Models

1998 ◽  
Vol 120 (3) ◽  
pp. 230-235 ◽  
Author(s):  
Haiyang Wang ◽  
M. E. Barkey
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Theoretical Development ◽  
Cyclic Plasticity ◽  
Numerical Implementation ◽  
Element Analysis ◽  
Surface Theory ◽  
Space Formulation ◽  
Strain Space

Strain space based plasticity models have certain advantages in theoretical development and numerical implementation. Previous efforts have been made to formulate cyclic plasticity models in strain space using the idea of multiple-yield surface theory. Recently, however, Armstrong-Frederick type plasticity models have received increasingly more attention because of their enhanced performance in predicting ratchetting behavior. In this paper, the strain space formulation of the Armstrong-Frederick family of cyclic plasticity models is established, and several representative strain controlled loading paths are used to compare the results from the proposed formulation and previous experimental data. The excellent agreement suggests the proposed strain space formulation is very promising in strain controlled cyclic plasticity such as finite element analysis, strain gage rosette applications, and multiaxial notch analysis using pseudo-stress or pseudo-strain approaches.

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