A Superposition Method for Nonlinear Crack Problems

2009 ◽  
pp. I-354-I-354-16
Author(s):  
G Yagawa ◽  
T Aizawa
Keyword(s):  
Superposition Method ◽  
Crack Problems ◽  
Nonlinear Crack

A superposition method for the solution of crack problems

1995 ◽  
Vol 11 (3) ◽  
pp. 243-254 ◽  
Author(s):  
R. N. L. Smith ◽  
D. Della-Ventura
Keyword(s):  
Superposition Method ◽  
Crack Problems

Studies of the Line-Spring Model for Nonlinear Crack Problems

1985 ◽  
Vol 107 (4) ◽  
pp. 412-420 ◽  
Author(s):  
V. Kumar ◽  
M. D. German
Keyword(s):  
Finite Element ◽  
Deformation Theory ◽  
Crack Tip ◽  
Surface Cracks ◽  
Spring Model ◽  
Crack Problems ◽  
Line Spring Model ◽  
Nonlinear Crack ◽  
Shell Finite Element ◽  
The Continuum

This paper presents an investigation of the line-spring model (LSM) of Rice and Levy as applied to nonlinear crack problems. A J2 deformation theory of plasticity formulation of a LSM for obtaining the fully plastic crack solutions is first described in the framework of a shell finite element method. Results are obtained for 2-D axial and circumferential cracks in cylinders and are compared against those developed by detailed finite element crack tip analyses. Discrepancies are found in the case of axially cracked cylinders under internal pressure. To overcome this problem a modified approach, termed the continuum-LSM, is presented, and its finite element implementation is described in some detail. It is shown that in contrast to the shell-LSM, the results obtained by the continuum-LSM for internally pressurized axially cracked cylinders are in close agreement with detailed finite element crack-tip calculations. Lastly, a discussion on the fully plastic analysis of surface cracks by the LSM is also given.

Structure Sensitivity Analysis and Dynamic Performance Optimization of Marine Gearbox

2017 ◽  
Author(s):  
Tengjiao Lin ◽  
Daokun Xie ◽  
Ziran Tan ◽  
Bo Liu
Keyword(s):  
Sensitivity Analysis ◽  
Performance Optimization ◽  
Optimization Design ◽  
Dynamic Performance ◽  
Structure Sensitivity ◽  
Superposition Method ◽  
Structure Parameters ◽  
Analysis Model ◽  
Vibration Acceleration ◽  
Response Optimization

The aim of this paper is to investigate the influence of structure parameters on the vibration characteristics and improve the dynamic performance of marine gearbox. A finite element model was established to solve the dynamic response by using modal superposition method. Based on the theory of multi-objective optimization design, the structure sensitivity analysis model of marine gearbox was established, which takes the structure parameters of the housing as design variables. The modal and response sensitivity was obtained by using the optimal gradient method. According to the results of sensitivity analysis, a modal and response optimization model of marine gearbox was established. The objective was to avoid natural frequencies from the excitation frequencies and minimize the root mean square of vibration acceleration of the evaluating points on the surface of housing. Then the modal optimization and response optimization of gearbox were carried out by using zero-order and first-order optimization method. The results indicate that the dynamic optimization of the gearbox can be achieved. After optimization, the amplitude of vibration acceleration of the evaluating points on the housing surface has been reduced and the resonance of marine gearbox can be avoided.

Shear response of steel fiber reinforced recycled concrete-filled steel tube columns

2021 ◽  
pp. 136943322110093
Author(s):  
Zhenzhen Liu ◽  
Yiyan Lu ◽  
Shan Li ◽  
Jiancong Liao
Keyword(s):  
Axial Compression ◽  
Steel Fiber ◽  
Steel Tube ◽  
Shear Capacity ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Superposition Method ◽  
Fiber Reinforced ◽  
Concrete Filled Steel Tube ◽  
Shear Span

A comprehensive study of the shear characteristics of steel fiber reinforced recycled concrete-filled steel tube (SRCFST) columns is conducted. 50 CFST stub columns are tested with the variables of steel tube diameter-thickness ratio ( D/t), shear span-to-depth ratio (λ), axial compression ratio ( n), and concrete mix. Two types of cements, three recycled aggregate percentages, three water-cement ratios, and three steel fiber contents are considered in design of concrete mixes. The experimental results show that SRCFST columns present the coincident shear behavior of the ordinary CFST columns. As λ is increased, shear resistance shows a downtrend, while the flexural strength presents an increasing trend. Imposing axial compression or thickening steel tube contributes to an adequate safety margin in plastic period. Based on the contributions superposition method, a predicted model of the shear capacity of SRCFST columns is proposed in consideration of shear-span ratio, axial compression, and self-stress.

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