08.36: Numerical modelling of circular CFST members and assessment of multi-axial stress state effects

ce/papers ◽  
2017 ◽  
Vol 1 (2-3) ◽  
pp. 2128-2137
Author(s):  
Yadong Jiang ◽  
Bledar Kalemi ◽  
António Silva ◽  
José Miguel Castro ◽  
Ricardo Monteiro
Keyword(s):  
Stress State ◽  
Numerical Modelling ◽  
Axial Stress

scholarly journals Non-destructive Assessment of the Axial Stress State in Iron and Steel Truss Structures by Dynamic Measurements

2017 ◽  
Vol 199 ◽  
pp. 3380-3385 ◽  
Author(s):  
Hoa T.M. Luong ◽  
Volkmar Zabel ◽  
Werner Lorenz ◽  
Rolf G. Rohrmann
Keyword(s):  
Stress State ◽  
Axial Stress ◽  
Truss Structures ◽  
Dynamic Measurements ◽  
Iron And Steel ◽  
Steel Truss ◽  
Non Destructive

Neutron Evaluation of Stress in Industrial Screws

2005 ◽  
Vol 490-491 ◽  
pp. 269-274
Author(s):  
Agnès Fabre ◽  
Ivan Lillamand ◽  
Jean-Éric Masse ◽  
Laurent Barrallier
Keyword(s):  
Stress State ◽  
Service Life ◽  
Neutron Diffraction ◽  
Axial Stress ◽  
Stress Gradient ◽  
In Situ Measurements ◽  
Nondestructive Technique

Neutron diffraction measurements were used in this study in order to determine the axial stress state in loaded screw from a specific assembly. The knowing of stress gradient is need to qualify a standard gauge used to calibrate the response of in-situ measurements using ultrasonic nondestructive technique. US is well adapted to perform measurements of the evolution of stress state on industrial screws during service life of the bolded assemblies.

scholarly journals Prediction of fatigue limit of journal bearings considering a multi-axial stress state

2016 ◽  
Vol 68 (3) ◽  
pp. 430-438 ◽  
Author(s):  
Christopher Sous ◽  
Henrik Wünsch ◽  
Georg Jacobs ◽  
Christoph Broeckmann
Keyword(s):  
Stress State ◽  
Axial Stress ◽  
Design Guidelines ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Test Results ◽  
Content Type ◽  
Operation Conditions ◽  
Component Test ◽  
Material Tests

Purpose The purpose of this paper is to investigate the applicability of the quadratic failure hypothesis (QFH) on journal bearings coated with a white metal sliding layer on the prediction of safe and unsafe operating conditions. The hypothesis covers operation conditions under static and dynamical loading. Design/methodology/approach Material tests and elastohydrodynamic, as well as structural, simulations were conducted to provide the required input data for the failure hypothesis. Component samples were tested to verify the results of the QFH. Findings The load bearing capacity of journal bearings was analysed for different operating conditions by the use of the QFH. Results allow for the identification of critical and non-critical loading conditions and are in accordance with component test results. Originality/value Today’s design guidelines for journal bearings do not consider a multi-axial stress state and actual stress distribution. The applied hypothesis enables consideration of multiaxiality inside the sliding surface layer, as well as determining the location of bearing fatigue due to material overload.

A Model for Determining Crack Opening Stress Intensity Factor Ratio under Tri-Axial Stress State

2005 ◽  
Vol 297-300 ◽  
pp. 1572-1578
Author(s):  
Yu Ting He ◽  
Feng Li ◽  
Rong Shi ◽  
G.Q. Zhang ◽  
L.J. Ernst ◽  
...  
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Stress State ◽  
Intensity Factor ◽  
Present Model ◽  
Axial Stress ◽  
Crack Opening ◽  
Factor Ratio ◽  
Crack Opening Stress ◽  
Good Agreement

When studying 3D fatigue crack growth behaviors of materials, to determine the crack opening stress intensity factor ratio is the key issue. Elastic-plastic Fracture Mechanics theory and physical mechanism of cracks’ closure phenomena caused by plastic deformation are employed here. A model for determining the crack opening stress intensity factor ratio under tri-axial stress state is presented. The comparison of the present model with available data and models shows quite good agreement.

Evaluation of Thermal Stress Ratchet in Plastic FEA

2002 ◽  
Author(s):  
Yukinori Yamamoto ◽  
Norimichi Yamashita ◽  
Masaaki Tanaka
Keyword(s):  
Finite Element ◽  
Thermal Stress ◽  
Stress State ◽  
Plastic Strain ◽  
Axial Stress ◽  
Equivalent Plastic Strain ◽  
Hardening Material ◽  
Linear Temperature ◽  
Stress Evaluation ◽  
Elastic Core

Alternative stress evaluation criteria suitable for Finite Element Analysis (FEA) proposed by Okamoto et al. [1] have been studied by the Committee on Three Dimensional Finite Element Stress Evaluation (C-TDF) in Japan. Thermal stress ratchet criteria in plastic FEA are now under consideration. Two criteria are proposed: evaluating variations in plastic strain increments and evaluating variations in the width of elastic core. To verify the validity of these criteria, calculations were performed for several typical models in C-TDF [2]. This paper shows the results of a simple cylinder model. Cyclic plastic analyses were performed applying sustained internal pressure and alternating linear temperature distribution through the wall. Analyses were performed with various load ranges to evaluate the precise ratchet limit and its behavior across the limit. Both pressure and thermal stress were given parameters. In the analyses, Elastic-Perfectly-Plastic (EPP) material was used and also strain hardening material for comparison. The ratchet limit in the Code [3] is based on Miller’s theoretical analysis [4] for a cylinder assuming a uni-axial stress state, whereas real vessels are in multi-axial stress state. By our calculations, we also examined the ratchet limit in real vessels. The results show that for the cylinder in a multi-axial stress state, the ratchet limit rises 1.2 times the ratchet limit by the Code. The evaluation results show that variations in equivalent plastic strain increments can be used for ratchet criterion and ratcheting can be assessed by confirming the presence of elastic core in the second cycle.

Determination of Forming Limit Diagrams for Thin Foil Materials Based on Scaled Nakajima Test

2015 ◽  
Vol 794 ◽  
pp. 190-198 ◽  
Author(s):  
Stefan Veenaas ◽  
Gerrit Behrens ◽  
Konstantin Kröger ◽  
Frank Vollertsen
Keyword(s):  
Stress State ◽  
Deep Drawing ◽  
Axial Stress ◽  
Forming Limit Diagram ◽  
Thin Foil ◽  
Chromium Steel ◽  
Forming Limit ◽  
Metal Foil ◽  
Forming Limit Diagrams ◽  
Process Understanding

For a better process understanding of micro deep drawing processes and reliable prediction of component failure in FE simulations, it requires the most accurate knowledge of actual material behaviour. However, it is not sufficient to describe material failure for a multi axial stress state in deep drawing using a mechanical parameter as the elongation from tensile test. A forming limit diagram and a forming limit curve are more suited to describe the limit of formability under deep drawing stress state conditions. Methods like hydraulic or pneumatic bulge tests are available to determine forming limit curves even for thin metal foil materials. Nevertheless, using these methods only positive minor strains can be achieved. Especially for a deep drawing process negative minor strains and the left side of a forming limit diagram are more important. Therefore, in this study, experiments based on scaled Nakazima tests were performed to determine complete forming limit diagrams for different foil materials with a thickness range of 20 µm to 25 µm. Scaling the test setup improves the handling of thin specimens. Results with a higher local resolution and the specimens’ size is much closer to the actual size of a micro deep drawn component. Using this testing method forming limit diagrams for the materials Al99.5, E-Cu58, stainless austenitic nickel-chromium steel X5CrNi18-10 (1.4301 / AISI 304), all produced by rolling, and an Al-Zr-foil, produced by a PVD sputtering process, were determined for the micro range.

Sign in / Sign up

Export Citation Format

Share Document