On the issue of choosing a technology for studying the stress state in the weld zone

NDT World ◽  
2021 ◽  
pp. 65-72
Author(s):  
Aleksey Antonov
Keyword(s):  
2018 ◽  
Vol 230 ◽  
pp. 01015
Author(s):  
Volodymyr Shramenko ◽  
Nataliia Bielikova ◽  
Olexandr Ovchinnikov ◽  
Dmytro Onopreichuk ◽  
Stanislav Horielyshev

The article defines the parameters and working conditions for the final restoration of the integrity of the rail beams of a continuous gauge rail by electrocontact welding, as well as when welding rails with each other when they are elongated in the field by the method of preliminary bending. This involves the process of welding rails at temperatures above the temperature of their fixation. In this connection, an appropriate calculation scheme has been considered in relation to which the necessary parameters have been determined to ensure the conditions for straightening the residual curvature and, as a consequence, the formations of the corresponding stress state. To ensure the self-straightening conditions, the resulting formula for determining the residual bending arrow, the elimination of which under the influence of its own weight leads to the appearance of compressive stresses in the weld zone. In addition, a formula has been derived for determining the compressive stresses in the weld zone arising in the rail after the elimination of residual curvature. This means that when performing welding operations without forced straightening of the rails, you can restore not only their integrity, or weld them together. Thereby form a corresponding temperature-stress state.


2015 ◽  
Vol 31 (1) ◽  
pp. 20-30 ◽  
Author(s):  
William S. Helton ◽  
Katharina Näswall

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.


2020 ◽  
Vol 118 (1) ◽  
pp. 108
Author(s):  
M.A. Vinayagamoorthi ◽  
M. Prince ◽  
S. Balasubramanian

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.


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