Interface Stress Simulation of 200kV Gas-filled Plug-in DC Cable Termination

Finite element weld residual stress modelling procedures involve complex non-linear analyses where many assumptions and approximations have to be made by the analyst. Weld modelling guidelines for inclusion in the R6 defect assessment procedure are in preparation and will be accompanied by a series of validation benchmarks that can be used to evaluate the accuracy of weld modelling procedures and assess their suitability for use in fracture assessments. It is intended to base one of the benchmarks on a stainless steel bead-on-plate weldment that has been extensively studied by members of Task Group 1 of the NeT European Network project. This paper uses round robin residual stress measurements from the NeT project to derive a statistically based ‘best estimate’ distribution of transverse stress passing through the wall-section at mid-length of the bead-on-plate weldment. The accuracy of a state-of-the-art residual stress prediction is benchmarked against the best estimate measurements using a root mean square error analysis and comparisons of decomposed components of stress. The appropriateness of using the predicted residual stresses in fracture assessments is assessed by comparing stress intensity factors based on the measured and predicted distributions of stress. The results from these studies will be used to help establish accuracy targets and acceptance criteria for the welding benchmark.

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Process stress simulation of medium-high carbon steel after hard-face-welding during martensite transformation

Computational Materials Science ◽

10.1016/j.commatsci.2008.03.034 ◽

2008 ◽

Vol 44 (2) ◽

pp. 280-285

Author(s):

Da Li ◽

Bo Liao ◽

Ligang Liu ◽

Chunmei Zhao ◽

Xiqing Zhao ◽

...

Keyword(s):

Carbon Steel ◽

Martensite Transformation ◽

High Carbon Steel ◽

High Carbon ◽

Stress Simulation ◽

Process Stress

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Revealing molecular conformation–induced stress at embedded interfaces of organic optoelectronic devices by sum frequency generation spectroscopy

Science Advances ◽

10.1126/sciadv.abf8555 ◽

2021 ◽

Vol 7 (16) ◽

pp. eabf8555

Author(s):

Zhongwu Wang ◽

Hongzhen Lin ◽

Xi Zhang ◽

Jie Li ◽

Xiaosong Chen ◽

...

Keyword(s):

Molecular Conformation ◽

Optoelectronic Devices ◽

Sum Frequency Generation ◽

Interface Stress ◽

Sum Frequency ◽

Device Stability ◽

Induced Stress ◽

Organic Optoelectronic Devices ◽

Organic Devices ◽

Organic Optoelectronic

Interface stresses are pervasive and critical in conventional optoelectronic devices and generally lead to many failures and reliability problems. However, detection of the interface stress embedded in organic optoelectronic devices is a long-standing problem, which causes the unknown relationship between interface stress and organic device stability (one key and unsettled issue for practical applications). In this study, a kind of previously unknown molecular conformation–induced stress is revealed at the organic embedded interface through sum frequency generation (SFG) spectroscopy technique. This stress can be greater than 10 kcal/mol per nm2 and is sufficient to induce molecular disorder in the organic semiconductor layer (with energy below 8 kcal/mol per nm2), finally causing instability of the organic transistor. This study not only reveals interface stress in organic devices but also correlates instability of organic devices with the interface stress for the first time, offering an effective solution for improving device stability.

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