Stress-relief borehole measurements before and after quarrying a block of Barre Granite at Barre, Vermont

1979 ◽  
Author(s):  
Danny R. Miller ◽  
G.E. Brethauer
Keyword(s):  
Stress Relief ◽  
Before And After ◽  
Barre Granite

Finite Element Modelling of a Series of Ground Displacement Episodes and Stress Relief Procedures

2019 ◽  
Author(s):  
Hamid Karimian ◽  
Pete Barlow ◽  
Chris Blackwell ◽  
Chris Campbell
Keyword(s):  
Finite Element ◽  
Stress Relief ◽  
Ground Movement ◽  
Ground Displacement ◽  
Ground Movements ◽  
Before And After ◽  
Translational Slide ◽  
Lower Slope ◽  
Upper Slope ◽  
Ground Displacements

Abstract The Wapiti River South Slope (the Slope) near Grand Prairie, Alberta, Canada, is 500 m long and consists of a steep lower slope and a shallower upper slope. Both the upper and the lower slopes are located within a landslide complex with ground movements of varying magnitudes and depths. The Alliance Pipeline (Alliance) NPS 42 Mainline (the pipeline) was installed in the winter of 2000 using conventional trenching techniques at an angle of approximately 8° to the slope fall line. Evidence of slope instability was observed in the slope since 2007. The surficial geology of the slope comprises a colluvium layer draped over bedrock formation in the lower slope, and glacial deposits in the upper slope. Available data indicated two different slide mechanisms. In the lower slope, there is a shallow translational slide within a colluvium layer, and in the upper slope there is a deep-seated translational slide within the glacial deposits. Both the upper and lower slope landslides have been confirmed to be active in the past decade. Gradual ground displacements in the order of several centimeters per year were observed in both the upper and lower slopes between 2007 and 2012. Large ground displacements in the order of several meters were observed between 2012 and 2014 in the lower slope that led to the first stress relief and subsequent slope mitigation measures in the spring and summer of 2014. Monitoring of the slope after mitigations indicated significant reduction in the rate of ground movement in the lower slope. Surveying of the pipeline before and after stress relief indicated an increase in lateral pipeline deformation in the direction of ground movement, following the stress relief. This observation raised questions regarding the effectiveness of partial stress relief to reduce stresses and strains associated with ground movements. Finite element analysis (FEA) was conducted in 2016 to aid in assessing the condition of the pipeline after being subject to ground displacements prior to 2014, stress relief in 2014, and subsequent ground displacement from July 2014 to December 2016. The results and findings of the FEA reasonably matched the observed pipeline behaviour before and after stress relief in the lower slope. The FEA results demonstrated that while the lateral displacement of the pipeline, originally caused by ground movement, increased following the removal of the soil loading during the stress relief, the maximum pipeline strain was reduced within the excavated portion. The FEA was also employed to assess the pipeline response to potential ground displacement scenarios following December 2016. For this assessment, three ground displacement scenarios that comprise different lengths of the pipeline were analyzed. An increased rate of ground displacement, with a pattern that matched one of the analyzed scenarios, was observed in the upper slope in the spring of 2017. The results of FEA were used to assess the pipeline response to the increased rate of displacement in the upper slope. Subsequently a decision was made to stress-relieve the pipeline. The second stress-relief was conducted in the summer of 2017. This stress relief was conducted locally at the toe and head of the active slide in the upper slope, where the FEA showed the greatest stress concentrations in the pipeline.

Considerations for Requiring Intermediate Stress Relief (ISR) for All Weld Types on 2 1/4 Cr-1 Mo-V Reactors

2010 ◽  
Author(s):  
Cathleen Shargay ◽  
Karly Moore ◽  
Timothy D. Breig ◽  
Les P. Antalffy ◽  
Michael M. Basic
Keyword(s):  
Heat Treatment ◽  
Postweld Heat Treatment ◽  
Stress Relief ◽  
Welding Defects ◽  
Before And After ◽  
Asme Code ◽  
Brittle Fractures ◽  
The Cost ◽  
Postweld Heat ◽  
Very High

As an industry consensus, API 934-A is an excellent recommended practice on the materials and fabrication requirements for Cr-Mo reactors. However, it is cautious and somewhat vague on the topic of Intermediate Stress Relief (ISR) versus Dehydrogenation Heat Treatment (DHT) for the different types of welds — which reflects the industry’s varying practices. For the advanced steels, API 934-A states that DHT should only be used with Purchaser approval, and that it should not be used on restrained welds such as nozzle welds. As a result, it is common for a DHT to be permitted on longitudinal and circumferential seams to achieve the cost and schedule savings, and ISR is used for nozzle welds. There are risks to the fabricator however, as the welds remain extremely brittle after DHT (the toughness is restored after postweld heat treatment {PWHT}, and at intermediate levels after ISR), and welding defects that are acceptable per ASME Code criterias can lead to brittle fractures during subsequent fabrication steps. The costs of the repairs and delays can then be very high, especially if the cracking is not detected until after PWHT. This paper shows the risks of acceptable defects causing brittle fractures by fracture mechanics calculations, and presents some case histories of cracking. The relative costs of ISR versus DHT, versus repairs before and after PWHT are also reviewed.

The Effect of Ground Displacement and Stress Relief on Pipeline Behaviour: A Case Study

2018 ◽  
Author(s):  
Hamid Karimian ◽  
Chris Campbell ◽  
Chris Blackwell ◽  
Colin Dooley ◽  
Pete Barlow
Keyword(s):  
Lateral Displacement ◽  
Stress Relief ◽  
Slope Instability ◽  
Ground Movement ◽  
Ground Displacement ◽  
Ground Movements ◽  
Before And After ◽  
Translational Slide ◽  
Lower Slope ◽  
Upper Slope

The Wapiti River South Slope is located 25 km southwest of Grande Prairie, AB. The slope is 500 m long and consists of a steep lower slope and a shallower upper slope, both of which are located within a landslide complex with ground movements of varying magnitudes and depths. The Alliance Pipelines Ltd. (Alliance) NPS 42 Mainline (the pipeline) was installed in the winter of 2000 using conventional trenching techniques at an angle of approximately 8° to the slope fall line. Evidence of slope instability was observed in the slope since the first ground inspection in 2007. Review of the available geotechnical data indicates two different slide mechanisms. In the lower slope, there is a shallow translational slide within a colluvium layer that is draped over a stable bedrock formation. In the upper slope, there is a deep-seated translational slide within glaciolacustrine and glacial till deposits that are underlain by pre-glacial fluvial deposits. Both the upper and lower slope landslide mechanisms have been confirmed to be active in the past decade. Large ground displacements in the order of several meters between 2012 and 2014 in the lower slope led to a partial stress relief and subsequent slope mitigation measures in the spring and summer of 2014, which significantly reduced the rate of ground movement in the lower slope. Surveying of the pipeline before and after stress relief indicated an increase in lateral pipeline deformation (in the direction of ground movement) following the stress relief. This observation was counter-intuitive and raised questions regarding the effectiveness of partial stress relief to reduce stresses and strains associated with ground movements. Finite element analysis (FEA) was conducted in 2017 to aid in assessing the condition of the pipeline after being subject to the aforementioned activities, and subsequent ground displacement from July 2014 to December 2016. This paper presents the assumptions and results of the FEA model and discusses the effect of large ground displacement, subsequent stress relief and continued ground displacement on pipeline behaviour. The results and findings of the FEA reasonably match the observed pipeline behaviour before and after stress relief. The FEA results showed that while the lateral displacement of the pipeline that was caused by ground movement actually increased following the removal of the soil loading, the maximum pipeline strain was reduced in the excavated portion. The results also indicated that ground displacement in the upper slope following the stress relief had minimal effect on pipe stresses and strains in the lower slope.

scholarly journals Scale, Material Concentration, Stress Relief and Part Removal Effects on the Dimensional Behaviour of Selected AlSi10Mg Components Manufactured by Laser Powder Bed Fusion

2019 ◽  
Vol 3 (2) ◽  
pp. 49
Author(s):  
Floriane Zongo ◽  
Antoine Tahan ◽  
Vladimir Brailovski
Keyword(s):  
Shot Peening ◽  
Scale Effects ◽  
Three Dimensional ◽  
Stress Relief ◽  
Computer Assisted ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Before And After ◽  
3D Profile

Laser Powder Bed Fusion (LPBF) is a predominant Additive Manufacturing (AM) process. While metallic LPBF is gaining popularity, one of the barriers facing its wider industrial use is the current relatively limited knowledge with respect to its dimensional and geometrical performance, as well as the inability to predict it. This paper presents an experimental investigation of the geometrical and dimensional deviations of selected LPBF-manufactured components according to the ASME Y14.5 (2009) standard. In this study, two types of axisymmetric parts (cylinder and cylindrical pyramid) were designed with three different levels of material concentration, and replicated at three different scales for a total of 18 test artifacts. These parts were manufactured from AlSi10Mg powder using an EOSINT M280 printer, subjected to stress relief annealing at 300 °C for two hours, removed from the platform and finished by micro shot peening. A complete statistical analysis was carried out on the artifacts before and after each post-processing step. The results of this investigation allowed for the quantification of the intra- (same part) and inter- (different parts) scale effects, as well as of the material concentration, stress relief, part removal and micro shot peening effects on the overall three-dimensional (3D) profile deviations and on the dimensional deviations of some selected features (e.g., diameter, thickness). For example, cylindrical pyramid parts showed the following average deviations of their outside diameters: a −63 µm shrinkage of the as-built part diameter as compared to its computer-assisted design (CAD) value, a +20 µm expansion after stress relief annealing as compared to the precedent step, a −18 µm shrinkage after part removal and, finally, a −50 µm shrinkage after micro shot peening.

Research on the Vibratory Stress Relief Used to Reduce Residual Stress of Mismatch Butt Welds of a Cylinder

2007 ◽  
Author(s):  
Xin Ren ◽  
Yuan Tian ◽  
Zengliang Gao ◽  
Kangda Zhang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Relief ◽  
Butt Weld ◽  
Butt Welds ◽  
Blind Hole ◽  
Dissimilar Steel ◽  
Weld Residual Stress ◽  
Before And After

The residual stresses of mismatch butt welds of a cylinder were measured by the blind-hole method before and after a vibratory residual stress relief treatment. The results show that this treatment could greatly reduce the maximal butt weld residual stress of dissimilar steel from 540MPa to 119MPa. The concentrated distributions of the first and the second principal residual stresses became gentle after the vibratory residual stress relief treatment.

Research on High-Frequency Vibratory Stress Relief of Small Cr12MoV Quenched Specimens

2012 ◽  
Vol 157-158 ◽  
pp. 1157-1161 ◽  
Author(s):  
Wen He ◽  
Bang Ping Gu ◽  
Jian Yi Zheng ◽  
Run Jie Shen
Keyword(s):  
Residual Stress ◽  
High Frequency ◽  
Low Frequency ◽  
Stress Relief ◽  
Vibration Level ◽  
High Frequency Vibration ◽  
Low Frequency Vibration ◽  
Before And After

Considering that most of the research on vibratory stress relief (VSR) is excited by low-frequency vibration at present, high-frequency-exciting VSR on small Cr12MoV quenched specimens was studied. A high-frequency vibration table system was adopted as the exciter of the VSR. To increase the vibration level, a novel vibration level amplifying device was put forward. High-frequency VSR on the same group of small Cr12MoV quenched specimens was carried out under various vibration levels. The residual stress before and after vibration was comparatively analyzed. The results showed that the high-frequency vibration had the better effect on eliminating and homogenizing the residual stress and that increasing the vibration level of high-frequency-exciting could improve the effect of high-frequency VSR.

Influence of Vibration on Thermomechanical Property and Transformation Behavior of TiNi Shape Memory Alloy

2014 ◽  
Vol 937 ◽  
pp. 341-345
Author(s):  
An Sheng Zheng ◽  
Rui Hua Li ◽  
Peng Shuang Zheng ◽  
Gui Ying Fu
Keyword(s):  
Stress Relief ◽  
Thermomechanical Property ◽  
Reverse Transformation ◽  
Tini Alloy ◽  
Heating Process ◽  
Transformation Behavior ◽  
Recoverable Strain ◽  
Recovery Strain ◽  
Before And After ◽  
The One

The strain recovery character and transformation behavior of a TiNi alloy are investigated by means of mechanical testing and DSC measurement before and after vibration. The DSC results show that the second reverse transformation peak temperature of TiNi alloys after vibration under constraint increases slightly during the subsequent heating, and the transformation heat decreases, while the transformation heat of the first reverse transformation increases. After constrained vibration, the first decline of the two-stage recovery strain obtained during the second heating process is obviously smaller than the one without vibration, and the total recoverable strain also decreases. For the prestrained martensitic TiNi fiber after a heating-cooling cycle, the two-way memory strain increases about 1.2% after vibration. All these phenomena are considered to be closely related to the vibratory stress relief during vibration.

Pipeline Stress Relief and Evaluation of Strain Measurement Technology at a Moving Slope

2014 ◽  
Author(s):  
Aaron Dinovitzer ◽  
Abdelfettah Fredj ◽  
Millan Sen
Keyword(s):  
Strain Measurement ◽  
Large Diameter ◽  
Stress Relief ◽  
Measurement Technology ◽  
Element Analysis ◽  
Soil Movement ◽  
Right Of Way ◽  
Bending Strain ◽  
Before And After ◽  
The Right

A major slope in southern Manitoba has been experiencing deep seated movements of approximately 60mm per year. This 24m high × 85m long slope contains a pipeline right of way with five large diameter crude oil lines that were constructed from 1950–1998. It is estimated that the slope has moved up to 3 meters since the pipeline installations. Management of the effects of this slope movement on the pipelines has involved cross-functional strategies that include geotechnical, integrity, and stress evaluations. A finite element analysis (FEA), which considers the interaction between the soil movement and pipeline, was generated to evaluate the pipeline stresses caused by the slope movements to date. The results indicated that the strain capacity on one of the pipelines may be near its limit. Correspondingly and in order to be conservative, a stress relief was conducted on three of the pipelines within the right-of-way. This mitigation involved excavating the pipelines 360 degrees which allowed for their decoupling from the surrounding soil, and the associated pipeline spring back was surveyed. Prior to backfilling, a low friction geotextile was installed around the excavated pipelines to help mitigate future movements. Drainage improvements and a toe berm were also installed to improve the slope stability. Several strain measurement technologies that have been the subject of previous Pipeline Research Council projects were also installed at the site. Stress probe measurements were taken before and after the stress relief; a fiber optic cable was installed; inline inspection bending strain measurements were analyzed; and the FEA analysis was used to model the strains before and after the stress relief. All of these technologies are compared to the measurements from strain gauges that were read both before and after the stress reliefs were conducted.

scholarly journals A Stress Relief App Intervention for Newly Employed Nursing Staff: Quasi-Experimental Design

10.2196/15785 ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. e15785
Author(s):  
I-Chiu Chang ◽  
Wei-Chen Cheng ◽  
Wen-Chuan Kung
Keyword(s):  
Stress Relief ◽  
Practical Experience ◽  
Control Group ◽  
Stress Levels ◽  
Before And After ◽  
Quasi Experimental ◽  
Group Members ◽  
Resistance To Stress ◽  
Depth Interviews ◽  
Experimental Group

Background Most newly employed nurses have limited practical experience, lack problem-solving abilities, and have low resistance to stress, and therefore often opt to resign from the nursing profession. Objective This study aimed to assess the effectiveness of a stress relief app (SR_APP) to monitor the stress levels of newly employed nurses. Methods We conducted a quasi-experiment to assess changes in stress levels of newly employed nurses at a case hospital, in which the experimental group used the SR_APP and the control group did not. In-depth interviews were conducted to reveal insights regarding their stress. The app usage experiences of experimental group members were assessed via a questionnaire. Results All the participants appreciated the experiment and were interested to know more about managing their stress. The experimental group members showed significant differences in heart rate variability scores before and after using the SR_APP, and they reported high levels of intention to use and satisfaction with regard to the SR_APP. Conclusions The SR_APP can be effective in helping newly employed nurses to manage their stress.

Research on Vibration Stress Relief for Cured SU-8 Photoresist Layer

2015 ◽  
Vol 1094 ◽  
pp. 487-490
Author(s):  
Qun Feng Yang ◽  
Jian Yi Zheng ◽  
Jun Qing Wang ◽  
Xue Nan Zhao ◽  
Da Yin Wei ◽  
...  
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Residual Stresses ◽  
Stress Relief ◽  
Excitation Current ◽  
Photoresist Layer ◽  
Before And After ◽  
Vibration Stress ◽  
Vibration Time ◽  
Vibration Parameters

The aim of this work is to reduce the residual stress in cured SU-8 Photoresist layer by vibration stress relief (VSR) method. The vibration device was designed according to the results of the ANSYS modal simulation, which was used for the thin film VSR. Meanwhile, some important influencing factors, such as the excitation current and the vibration time, have been discussed. The residual stress in the SU-8 layer was measured by profile method, and the values of residual stresses in the SU-8 layer before and after VSR were compared. The experimental results show that residual stress in SU-8 layer can be effectively eliminated or homogenized by VSR if the proper vibration parameters were chosen in the experiment.

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