scholarly journals Unidirectional compression of fibre reinforcements. Part 1: A non-linear elastic-plastic behaviour

2007 ◽  
Vol 67 (3-4) ◽  
pp. 507-514 ◽  
Author(s):  
S. Comas-Cardona ◽  
P. Le Grognec ◽  
C. Binetruy ◽  
P. Krawczak
Keyword(s):  
Elastic Plastic ◽  
Linear Elastic ◽  
Plastic Behaviour ◽  
Non Linear

Multiaxial Fatigue Life Prediction for Notched Components under Proportional and Non-Proportional Cyclic Loading

2012 ◽  
Vol 197 ◽  
pp. 585-589
Author(s):  
Hong Chen ◽  
De Guang Shang ◽  
Yu Jie Tian ◽  
Guang Wei Xu
Keyword(s):  
Fatigue Life ◽  
Cyclic Loading ◽  
Life Prediction ◽  
Elastic Solution ◽  
Fatigue Life Prediction ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Equivalent Parameter ◽  
Non Linear ◽  
Notched Components

Fatigue life estimation of notched components is mostly dependent on notch stress and strain calculation with non-linear finite element analysis (FEA). For multiaxial cyclic loading, the stress-strain analysis of notch root is rather complex and the non-linear FEA is also very time-consuming. In this paper, a new fatigue life prediction method for notched components under multiaxial loading is proposed. First, a linear elastic solution needs to be solved for notched components under multiaxial cyclic loading. Then, an elastic equivalent parameter is computed using the linear elastic solution. On the basis of the elastic equivalent parameter combined with the Neuber’s rule, an elastic-plastic equivalent parameter is obtained. Finally, the elastic-plastic equivalent parameter is used to estimate fatigue crack initiation life of notched components. The proposed method needs only elastically calculated notch strain history as the basic input and is convenient for engineering application. The method is verified with experimental data of SAE 1045 notched shaft specimens under proportional and non-proportional loading. The results showed that the method can provide good life estimates.

A non-linear elastic-plastic stress analysis in a ductile double-lap joint

2012 ◽  
Vol 0 (0) ◽  
pp. 1-6 ◽  
Author(s):  
Onur Sayman ◽  
Mustafa Ozen ◽  
Adnan Ozel ◽  
Teyfik Demir ◽  
Behiye Korkmaz
Keyword(s):  
Stress Analysis ◽  
Lap Joint ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Non Linear ◽  
Plastic Stress

On the Effect of Scattering of Bolt Forces on Gasket Stress

2006 ◽  
Author(s):  
Manfred Schaaf ◽  
Friedrich Schoeckle ◽  
Jaroslav Bartonicek
Keyword(s):  
Plastic Material ◽  
Analytical Calculation ◽  
Large Degree ◽  
Outer Diameter ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Non Linear ◽  
Realistic Description ◽  
Lift Off ◽  
Elastic Plastic Material

To guarantee integrity and tightness of bolted flanged connections a set of gasket characteristics (for tightness e.g. QMIN(L), QSMIN(L), tightness class L) has to be known. These characteristics are determined in simplified standardized tests with uniform gasket stress levels, in which the effect of the scattering of the bolt force is neglected. In this paper, results of Finite Element studies with real flange models are presented in which the local distribution of the gasket stress was determined in dependence of the scatter of the bolt forces. In the calculations, different models of the material characteristics are evaluated. A linear elastic approach, a nonlinear elastic approach and a non-linear elastic-plastic approach of the gasket behaviour is analysed. The results of the FEM studies demonstrated that elastic-plastic material laws are necessary for a realistic description of the material behaviour. The calculations in which the elastic-plastic gasket behaviour is considered give a nearly uniform gasket stress distribution along the gasket circumference despite a large scatter in the bolt force. This means that a non-uniform load transmission into the BFC is “damped” through the flange rings to a large degree and the gasket is compressed almost uniformly along the circumference. In radial direction an increase of the gasket stress from the inner to the outer diameter can be observed. Depending on the material law used, a lift-off of the flange ring from the gasket at the inner diameter (caused by the flange rotation) is obtained (linear elastic approach). Using a non-linear elastic or elastic-plastic approach for the gasket material the gasket stays in contact with the flange surfaces over the entire width of the gasket. These experiences can only partly be considered in analytical calculation codes such as EN 1591-1 (1). This is one reason why there are often discussions about the tightening factors of different mounting procedures and therefore difficulties in stress and tightness analysis can occur.

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