The Characteristics of the Magnetic Memory Signals under Different States for Q235 Defect Samples

2010 ◽  
Vol 97-101 ◽  
pp. 500-503 ◽  
Author(s):  
Jian Wei Li ◽  
Min Qiang Xu ◽  
Jian Cheng Leng ◽  
Ming Xiu Xu
Keyword(s):  
Stress State ◽  
Tensile Stress ◽  
Magnetic Behavior ◽  
Ferromagnetic Materials ◽  
Magnetic Memory ◽  
Testing Environment ◽  
Memory Signals ◽  
Stress States ◽  
Testing Environments ◽  
Different Characteristics

Magnetic behavior of ferromagnetic materials has been using to detect defects of materials. To evaluate the stress states of the components by the magnetic memory signal, Q235 defect asymmetrical samples were made. The characteristics of magnetic memory of Q235 have been studied in the three different testing environments which are online-loading, online-unloading and offline-unloading under cycle tensile stress. The results show that magnetic memory signals have different characteristics in different testing environment. It is feasible to evaluate preliminarily the stress state by the magnetic memory signals.

Effect of tensile stress on metal magnetic memory signals during on-line measurement in ferromagnetic steel

2021 ◽  
Vol 117 ◽  
pp. 102378
Author(s):  
Huipeng Wang ◽  
Lihong Dong ◽  
Haidou Wang ◽  
Guozheng Ma ◽  
Binshi Xu ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Line Measurement ◽  
On Line ◽  
Memory Signals ◽  
Ferromagnetic Steel

scholarly journals The Magnetic Memory Effect of Ferromagnetic Materials in the Process of Stress-Magnetism Coupling

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Guoqing Wang ◽  
Ping Yan ◽  
Liwa Wei ◽  
Zilong Deng
Keyword(s):  
Experimental Investigation ◽  
Memory Effect ◽  
Magnetic Characteristic ◽  
Ferromagnetic Material ◽  
Practical Method ◽  
Ferromagnetic Materials ◽  
Magnetic Memory ◽  
Coupling Process ◽  
Inflection Points ◽  
Memory Signals

Ferromagnetic materials can produce the magnetic memory effect under stress. This provides a practical method to measure stress concentration. The relation between stress and magnetic characteristic is analyzed through energy balance theory. Force-magnetism coupling process of Fe-C crystal system is simulated by CASTEP software which is based on first principle. Electron band structure, electron density of states, and atomic magnetic moment in the process of force-magnetism coupling process are calculated. Experimental investigation of the magnetic memory effect of ferromagnetic material under different stresses has been undertaken in X52 pipeline. The results show that the magnetic characteristic of ferromagnetic material weakens under stress, and the magnetic memory signals intensity linearly decreases with the increasing stress. When material yields, the variation character of magnetic memory signals suddenly changes and the inflection points of the stress-Bcurves emerge. Experimental investigation is in agreement with the theoretical analysis.

Study of Pre-Stress Effect of Ribcage Structure on Chest Response of Crash Dummy Model

2010 ◽  
Author(s):  
Xinghua Lai ◽  
Qing Zhou
Keyword(s):  
Stress State ◽  
Tensile Stress ◽  
Compressive Stress ◽  
Fe Model ◽  
Stress Effect ◽  
Stress Model ◽  
Test Results ◽  
Hybrid Iii ◽  
Structural Responses ◽  
Stress States

Assembling induced pre-stress state commonly exists in the ribcage structure of Hybrid III dummy hardware. In the practice of dummy modeling, however, the pre-stress issue is often neglected. This study is intended to assess the pre-stress effect on chest response of the Hybrid III 50th percentile male dummy model. In this paper, how the pre-stress state is generated in the dummy ribcage assembling process is first elaborated by disassembling and reverse engineering a physical dummy chest structure. A thorax FE model is then built and validated against test results. Using finite element modeling approach, the structural responses with and without the pre-stress state are compared and analyzed at single rib, ribcage and full dummy levels and under a number of loading conditions. The study has found out that, there are two common pre-stress states existing in the rib components of the dummy ribcage, pre-compressive stress and pre-tensile stress. Compared with no pre-stress model, the pre-compressive stress makes a rib stiffer and the pre-tensile stress makes a rib less stiff. It is further concluded that, the pre-stress effect is significant at the single rib level and insignificant at the ribcage level and the full dummy level. This is mainly because the effects of the pre-compressive stress and the pre-tensile stress existing in the six ribs are compensated each other in the assembled ribcage. Therefore, neglecting the pre-stress effect of the ribcage structure in the dummy models is reasonable.

Short Stress State Questionnaire

2015 ◽  
Vol 31 (1) ◽  
pp. 20-30 ◽  
Author(s):  
William S. Helton ◽  
Katharina Näswall
Keyword(s):  
Stress State ◽  
Factor Structure ◽  
Human Performance ◽  
Self Report ◽  
Confirmatory Factor ◽  
Stress States ◽  
Related Stress ◽  
Using Data ◽  
Task Conditions ◽  
Multiple Samples

Conscious appraisals of stress, or stress states, are an important aspect of human performance. This article presents evidence supporting the validity and measurement characteristics of a short multidimensional self-report measure of stress state, the Short Stress State Questionnaire (SSSQ; Helton, 2004 ). The SSSQ measures task engagement, distress, and worry. A confirmatory factor analysis of the SSSQ using data pooled from multiple samples suggests the SSSQ does have a three factor structure and post-task changes are not due to changes in factor structure, but to mean level changes (state changes). In addition, the SSSQ demonstrates sensitivity to task stressors in line with hypotheses. Different task conditions elicited unique patterns of stress state on the three factors of the SSSQ in line with prior predictions. The 24-item SSSQ is a valid measure of stress state which may be useful to researchers interested in conscious appraisals of task-related stress.

scholarly journals Mesoscale Modelling of Concretes Subjected to Triaxial Loadings: Mechanical Properties and Fracture Behaviour

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1099
Author(s):  
Qingqing Chen ◽  
Yuhang Zhang ◽  
Tingting Zhao ◽  
Zhiyong Wang ◽  
Zhihua Wang
Keyword(s):  
Mechanical Properties ◽  
Tensile Stress ◽  
Failure Criterion ◽  
Mesoscale Model ◽  
Fracture Behaviour ◽  
Descent Method ◽  
Triaxial Stress ◽  
Gradient Descent Method ◽  
Stress States ◽  
Shear Failures

The mechanical properties and fracture behaviour of concretes under different triaxial stress states were investigated based on a 3D mesoscale model. The quasistatic triaxial loadings, namely, compression–compression–compression (C–C–C), compression–tension–tension (C–T–T) and compression–compression–tension (C–C–T), were simulated using an implicit solver. The mesoscopic modelling with good robustness gave reliable and detailed damage evolution processes under different triaxial stress states. The lateral tensile stress significantly influenced the multiaxial mechanical behaviour of the concretes, accelerating the concrete failure. With low lateral pressures or tensile stress, axial cleavage was the main failure mode of the specimens. Furthermore, the concretes presented shear failures under medium lateral pressures. The concretes experienced a transition from brittle fracture to plastic failure under high lateral pressures. The Ottosen parameters were modified by the gradient descent method and then the failure criterion of the concretes in the principal stress space was given. The failure criterion could describe the strength characteristics of concrete materials well by being fitted with experimental data under different triaxial stress states.

scholarly journals A Study of Yielding and Plasticity of Rapid Prototyped ABS

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1495
Author(s):  
Dan-Andrei Șerban ◽  
Cosmin Marșavina ◽  
Alexandru Viorel Coșa ◽  
George Belgiu ◽  
Radu Negru
Keyword(s):  
Experimental Data ◽  
Stress State ◽  
Plastic Flow ◽  
Plane Stress ◽  
Yield Criterion ◽  
Numerical Analyses ◽  
Flow Potential ◽  
Stress States ◽  
State Configuration

In this article, the yielding and plastic flow of a rapid-prototyped ABS compound was investigated for various plane stress states. The experimental procedures consisted of multiaxial tests performed on an Arcan device on specimens manufactured through photopolymerization. Numerical analyses were employed in order to determine the yield points for each stress state configuration. The results were used for the calibration of the Hosford yield criterion and flow potential. Numerical analyses performed on identical specimen models and test configurations yielded results that are in accordance with the experimental data.

The Feature Extraction Method of Gear Magnetic Memory Signal

2013 ◽  
Vol 819 ◽  
pp. 206-211
Author(s):  
Yong Gang Xu ◽  
Zhi Cong Xie ◽  
Lin Li Cui ◽  
Jing Wang
Keyword(s):  
Gear Tooth ◽  
Low Frequency ◽  
Magnetic Memory ◽  
Magnetic Signal ◽  
Heavy Load ◽  
Low Speed ◽  
Feature Extraction Method ◽  
Test Technology ◽  
Time Scale Decomposition ◽  
Memory Signals

Magnetic memory test technology is a new nondestructive testing technique, which is able to detect of the stress concentration area and potential fault of low speed and heavy load gear. Because the magnetic memory signals are easy to be disturbed by various sources of noises, a new method based on the intrinsic time-scale decomposition (ITD) is proposed to achieve the extraction of magnetic memory signal. Firstly, the magnetic memory signals are decomposed into several proper rotation components (PRC) and a trend component by ITD. Then reconstruct the first four order PRCs to eliminate the low frequency cyclic composition of magnetic memory signal and magnetic noise. Finally, the magnetic signal strengths of each gear tooth root are extracted using cycle average and local statistic method. The results of Experiments show that the method is suitable to pick up effective ingredients of signal to extract signal feature and has important application value in potential fault diagnosis of low speed and heavy load gearbox.

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