Experimental Study on the Strain Softening Behavior of Plate Anchors in Clay Under Cyclic Loading

2014 ◽  
Author(s):  
Long Yu ◽  
Qi Zhou ◽  
Jun Liu
Keyword(s):  
Cyclic Loading ◽  
Bearing Capacity ◽  
Stress Level ◽  
Strain Softening ◽  
High Stress ◽  
Offshore Structures ◽  
Pullout Capacity ◽  
Softening Behavior ◽  
Plate Anchors ◽  
High Stress Level

Many geotechnical designs require knowledge of soil uplift resistance where the foundation must withstand tensile forces, such as wind loading on transmission towers, wave action on offshore structures, and buoyancy forces on buried pipelines. Most existing researches on the bearing capacity of plate anchors are limited to static analyses. The effects of offshore cyclic loading on the bearing capacity of plate anchors are not very clear. The ultimate pullout capacity of plate anchors in clay may decrease as the accumulated plastic shear strain grows due to the strain-softening of clay under cyclic loading. In this study, 1 g model tests were carried out to estimate the softening behavior of plate anchors including one low stress level case and two high stress level cases. PIV (Particle Image Velocimetry) technique was used to investigate the soil flow mechanism of the anchor at low stress level. Numerical analyses are carried out to simulate the large deformation behavior of the anchor at high stress level under cyclic loading.

Residual modulus of elasticity and maximum compressive strain in HSC and FRHSC after high-stress-level cyclic loading

2014 ◽  
Vol 15 (2) ◽  
pp. 210-218 ◽  
Author(s):  
Miguel A. Vicente ◽  
Dorys C. González ◽  
Jesús Mínguez ◽  
José A. Martínez
Keyword(s):  
Cyclic Loading ◽  
Stress Level ◽  
Modulus Of Elasticity ◽  
Compressive Strain ◽  
High Stress ◽  
High Stress Level

scholarly journals Researches on the Constitutive Models of Artificial Frozen Silt in Underground Engineering

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yugui Yang ◽  
Feng Gao ◽  
Hongmei Cheng ◽  
Yuanming Lai ◽  
Xiangxiang Zhang
Keyword(s):  
Mechanical Characteristic ◽  
Stress Level ◽  
Strain Softening ◽  
Triaxial Compression ◽  
High Stress ◽  
Constitutive Models ◽  
Confining Pressure ◽  
Frozen Soil ◽  
Conventional Triaxial Compression ◽  
Shear Process

The researches on the mechanical characteristic and constitutive models of frozen soil have important meanings in structural design of deep frozen soil wall. In the present study, the triaxial compression and creep tests have been carried out, and the mechanical characteristic of frozen silt is obtained. The experiment results show that the deformation characteristic of frozen silt is related to confining pressure under conventional triaxial compression condition. The frozen silt presents strain softening in shear process; with increase of confining pressure, the strain softening characteristic gradually decreases. The creep curves of frozen silt present the decaying and the stable creep stages under low stress level; however, under high stress level, once the strain increases to a critical value, the creep strain velocity gradually increases and the specimen quickly happens to destroy. To reproduce the deformation behavior, the disturbed state elastoplastic and new creep constitutive models of frozen silt are developed. The comparisons between experimental results and calculated results from constitutive models show that the proposed constitutive models could describe the conventional triaxial compression and creep deformation behaviors of frozen silt.

Implementation of K-Modes Algorithm for Clustering of Stress Causes in University Students

2021 ◽  
Vol 9 (3) ◽  
pp. 419
Author(s):  
Ni Putu Mira Novita Dewi ◽  
Ida Bagus Gede Dwidasmara
Keyword(s):  
Stress Level ◽  
Clustering Algorithm ◽  
High Stress ◽  
Optimal Number ◽  
Mild Stress ◽  
Student Groups ◽  
High Stress Level ◽  
Internal And External Factors ◽  
Python Programming ◽  
Cluster 2

Stress is an inevitable part of life in a college environment. The variety of factors that cause stress in students, it is necessary to cluster the factors that cause stress in students to see the description of the characteristics of each cluster of students. The clustering process is carried out to identify the causes of stress in student groups and their relationship to these internal and external factors. Cluster analysis can be used as a reference to decide on efforts to handle and prevent increased stress in students. The clustering process is carried out using the Python programming language. The algorithm used is the k-modes clustering algorithm. This algorithm is suitable for clustering categorical data. The optimal number of clusters obtained from the implementation of the elbow method is three clusters. Cluster 1 is a cluster with a mild stress level, the main cause of stress is academic issues. Cluster 1 is the only group where the majority of the cause of stress is not financial. Cluster 2 is a cluster with a high stress level which causes various stressors. However, cluster 2 is the only cluster where the cause of stress is on careers and on involvement in hostels, clubs, and society. Cluster 3 is a cluster with a medium stress level. This cluster is the only cluster dominated by male gender. The main cause of stress in this cluster is academic and financial.

scholarly journals Study on the Effect of Laser Quenching on Fretting Fatigue Life

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 566 ◽  
Author(s):  
Hongjian Zhang ◽  
Xufeng Yang ◽  
Haitao Cui ◽  
Weidong Wen
Keyword(s):  
Fatigue Life ◽  
Stress Level ◽  
High Stress ◽  
Fretting Fatigue ◽  
Test System ◽  
Experimental Results ◽  
Laser Quenching ◽  
Error Band ◽  
Hydraulic Servo ◽  
High Stress Level

Laser quenching hardening is one of the most used surface treated technologies. In order to study the effect of laser quenching on the fretting fatigue life, fretting fatigue experiments of TC11 (Ti-6.5Al-1.5Zr-3.5Mo-0.3Si) titanium alloy specimens with different surface conditions were carried out on a special hydraulic servo fatigue test system. The experimental results showed that laser quenching hardening has a good performance in increasing the fretting fatigue lives of the TC11 alloy. However, the effects of laser quenching on fretting fatigue are more obviously at low stress level than at high stress level, the fretting fatigue life was increased by 110.78% at low stress level and 17.56% at high stress level, respectively. Based on the critical plane approach, the traditional SWT (Smith–Watson–Topper) parameter was modified and used to describe the fretting fatigue life of the TC11 alloy after hardening by the consideration of the variations of the hardening layer’s elastic modulus. Compared with the experimental results, all the errors of the predicted results lied in the error band of two.

scholarly journals Small-strain behaviour and crushability of Ballyconnelly carbonate sand under monotonic and cyclic loading

2018 ◽  
Vol 55 (7) ◽  
pp. 979-987 ◽  
Author(s):  
S. Nanda ◽  
V. Sivakumar ◽  
S. Donohue ◽  
S. Graham
Keyword(s):  
Cyclic Loading ◽  
Large Scale ◽  
Sea Water ◽  
High Stress ◽  
Small Strain ◽  
Offshore Structures ◽  
Particle Breakage ◽  
Triaxial Tests ◽  
Bender Element ◽  
Carbonate Sand

In various parts of the globe, carbonate sands are found at shallow sea water depth. These types of sands are very susceptible to large-scale particle breakage. Offshore structures like wind turbines and sea defences are constructed on these types of soils. From a design perspective, it is essential to assess the extent of particle breakage and the subsequent change in soil properties that occur under working load conditions. This paper presents the data obtained from a number of drained monotonic and cyclic triaxial tests on crushable carbonate sand (“Ballyconnelly sand”) in conjunction with small-strain shear stiffness (Gmax) measurements using the bender element technique. The soils were allowed to shear under three different loading patterns to understand the factors influencing the breakage of particles. The degree of crushing was quantified and analysed based on the total energy input. It was observed that, apart from applied stress, the total strain accumulation governs the amount of particle breakage. It was observed that Gmax increased significantly under high stress ratio. Gmax also increased noticeably during resting periods without any change in loading conditions as a result of creep, and subsequently during cyclic loading although at a reduced rate.

Genetic susceptibility of CYP1A1 gene and risk of pesticide exposure in prostate cancer

2020 ◽  
Vol 29 (4) ◽  
pp. 429-440
Author(s):  
Amar Abhishek ◽  
Nasreen Ghaji Ansari ◽  
Vishwajeet Singh ◽  
Rahul Janak Sinha ◽  
Prabhakar Mishra ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Stress Level ◽  
Genetic Factors ◽  
Pesticide Exposure ◽  
High Stress ◽  
P Value ◽  
Specific Pcr ◽  
Cyp1a1 Gene ◽  
High Stress Level ◽  
High Level

BACKGROUND: The etiology of prostate cancer (PCa) is multi-factorial including environmental and genetic factors. Present study evaluates the association between level of pesticides, stress level and CYP1A1 gene polymorphism with PCa patients. METHODS: A case control study was conducted with 102 PCa patients and age match symptomatic (n= 107) and asymptomatic benign prostatic hyperplasia (BPH, n= 70) patients. Pesticide level was characterized by Gas Chromatography. The oxidative stress and scavenging mechanisms were determined by biochemical method. Two polymorphisms of CYP1A1 gene, rs4646903 and rs1048943, were analyzed by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism and allele specific PCR method. RESULTS: Higher level of pesticide namely beta-hexachlorocyclohexane (β-HCH), Malathion, Chlorpyrifos and Fenvalerate were found in PCa group (all p value: < 0.05). Kruskal Wallis H test depicted that level of β-HCH and Malathion significantly correlated with higher grade of PCa (all p< 0.05). The PCa Patients with simultaneously low antioxidant activity and high stress level tended to suffer worst clinical outcomes. Dominant model of rs4646903 and rs1048943 suggested that substitution is associated with a higher risk of PCa (OR: 2.2, CI: 1.6–3.8, p: 0.009 and OR: 1.95, CI: 1.1–3.4, p: 0.026; respectively) and this risk was also influenced by smoking and pesticide exposure. CONCLUSION: Environmental and genetic factors are reported to raise risk; person with high level of these pesticides especially in high risk genotype might be more susceptible to PCa.

Distress screening in patients with urogenital malignancies.

2017 ◽  
Vol 35 (6_suppl) ◽  
pp. 412-412
Author(s):  
Pia Paffenholz ◽  
Maria Angerer-Shpilenya ◽  
Johannes Salem ◽  
David Pfister ◽  
Axel Heidenreich
Keyword(s):  
Psychological Distress ◽  
Stress Level ◽  
Malignant Tumors ◽  
High Stress ◽  
Salvage Treatment ◽  
Distress Screening ◽  
Prospective Longitudinal Study ◽  
Psychological Burden ◽  
High Stress Level ◽  
Prospective Longitudinal

412 Background: Malignant tumors do not only have a somatic but also a psychological impact on patients. To date, only a few studies are available which evaluated the potential psychological burden of patients suffering from urogenital cancers. In this prospective, longitudinal study we examine the baseline psychological distress of patients treated for urogenital malignancies focussing on testicular cancer (TC) and prostate cancer (PCA). Methods: Psychological distress of 192 inpatients treated for urogenital malignancies was evaluated using the distress thermometer (DT), an established tool for the detection of distress, prior to any surgical or systemic therapy. The DT consists of a visual analogue scale ranging from 0 to 10 resulting in a low (0-3), moderate (4-6) or high (7-10) stress level. Furthermore, it contains a 36-item list of problems subdivided into 5 categories (practical, family, emotional, spiritual/religious, physical). Results: The mean DT score was 5 (interquartile range (IQR) 3-7) with the most common stressors being of emotional origin, namely fear (50%), worry (44%), nervousness (42%), sleep disorders (39%) and fatigue (32%). DT analysis did not reveal any difference between the tumor entities but 64% of all patients displayed a moderate to high stress level requiring psycho-oncological support. The comparison of PCA and TC demonstrated a higher distress level in PCA patients in the subgroups of metastatic disease (median 5.5, IQR 4-8 vs. median 4, IQR 2-6; p = 0.018), secondary therapy (median 6, IQR 5-8 vs. median 4.5, IQR 2.75-6; p = 0.023) and salvage treatment (median 7, IQR 4.5-9 vs. 5, IQR 2.75-6; p = 0.021). PCA patients receiving salvage treatment displayed significantly higher distress levels compared to non-salvage treated patients (median 7, IQR 4.5-9 vs. median 5, IQR 2-7; p 0.028). Conclusions: Our study shows that 64% of urological tumor patients should be offered psycho-oncological support. Especially patients suffering from advanced stage PCA seem to have a high stress level. Thus, physicians in the field of urologic oncology should be aware of their patients’ psychological distress in order to identify high-risk patients and provide them with an appropriate psycho-oncological support.

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