Stress and Strain Intensity Factors of the Corner Area of the Structure Boundary

2018 ◽  
Vol 931 ◽  
pp. 30-35
Author(s):  
Lyudmila U. Frishter
Keyword(s):  
Strain State ◽  
Practical Significance ◽  
Engineering Practice ◽  
Stress And Strain ◽  
Building Structures ◽  
Strain Intensity ◽  
Intensity Factors ◽  
Plane Region ◽  
The Difference ◽  
Irregular Point

The Stress and strain state of building structures in zones with bird's mouths and cuts of the boundary is characterized by stress concentration zones emergence and requires an evaluation of strength and reliability of objects, which is the engineering practice actual task. Theoretical analysis of stress and strain state of bird's mouth areas of the region boundary is confined to the study of singular solutions of the elasticity problem with power singularities. In this case, the concept of stress or strain concentration at an irregular point of the region boundary becomes meaningless. In the present article, stress and strain state is considered in the neighborhood of the bird's mouth vertex of the boundary of a plane region, which is written with the help of the intensity factors. Two approaches are given to obtaining the expressions for displacements, stresses in the neighborhoods of an irregular point of the boundary of a plane region by means of stress intensity factors and strain intensity factors. The difference in the expressions for stresses and displacements obtained for the limiting values of stresses and strains determines the practical significance of the work during the experiments and the determination of the critical values of stresses and strains.

scholarly journals Comparison of the stress and strain intensity factors for the corner area of the structure boundary

2018 ◽  
Vol 193 ◽  
pp. 03029
Author(s):  
Lyudmila Frishter
Keyword(s):  
Strain State ◽  
Engineering Practice ◽  
Stress And Strain ◽  
Strain Intensity ◽  
Intensity Factors ◽  
Stress Strain ◽  
Elasticity Theory Problem ◽  
Limit Values ◽  
Stress Strain State ◽  
Irregular Point

The stress-strain state of structures in areas with corner cut-outs and cuts of boundaries features the occurrence of areas of stress concentration and requires assessment of strength and reliability of facilities, which is a relevant task in engineering practice. Theoretical analysis of stress-strain state (SSS) of corner cut-outs zones of the area boundary is reduced to the study of singular solutions of the elasticity theory problem with exponential features. At that, the concept of stress or strain concentration in an irregular point of the area boundary is meaningless. This paper considers the stress-strain state in the vicinity of the top of the corner cut-out of the flat area boundary, which is recorded using the intensity factors as limit values of stresses and strains. We give two approaches for obtaining the limit values for stress and strain in the vicinity of an irregular point of the plane area boundary using the stress intensity factors and the strain intensity factors. The stress-strain state in the corner cut-outs zone of structures and buildings boundary recorded in the form of limit values of stresses and strains may further be used to determine and record the influence of changing the factors of intensity of stresses and strains on SSS of structures, which is a separate task of solid mechanics. The difference in the expressions of stresses and displacements obtained for limit values of stresses and strains determines practical significance of the work when carrying out experiments and at determination of critical values of stresses and strains.

scholarly journals INVESTIGATION OF STRESS-STRAIN STATE OF “RESTORATION & TOOTH” SYSTEM IN WEDGE-SHAPED DEFECTS BY COMPUTED MODELING METHOD

2021 ◽  
Vol 74 (9) ◽  
pp. 2112-2117
Author(s):  
Natalia N. Brailko ◽  
Iryna M. Tkachenko ◽  
Victor V. Kovalenko ◽  
Anna V. Lemeshko ◽  
Alexey G. Fenko ◽  
...  
Keyword(s):  
Tangential Stress ◽  
Strain State ◽  
Adhesive Layer ◽  
Biomechanical Analysis ◽  
Stress And Strain ◽  
Restorative Material ◽  
Stress Strain ◽  
Stress Strain State ◽  
Small Height ◽  
The Difference

The aim of this research is to study the influence of size and location of wedge-shaped defects of teeth on stress and strain state of restorative material on the basis of biomechanical analysis. Materials and methods: Biomechanical analysis of the stress-strain state was performed on a jaw bone fragment with canine and premolar inclusion. Results: Tangential stress increase both in the adhesive layer and in restorative material with depth and width (medial-distal size) of restored wedge-shaped defects of teeth,. The most unfavorable loading on a tooth is a joint action of vertical and horizontal loading in lingual- vestibular or vestibular-lingual direction, depending on localization of the restored wedge-shaped defects of teeth. The formation of retention grooves in wedge-shaped defects of teeth reduces the value of the maximum tangential stress in the adhesive layer of restorative material to 25% and extends the longevity of restorations. Conclusions: The difference in maximal values of tangential stress increases in adhesive layer of restorative material with or without retention grooves with increasing depth of defect. Thus, it is advisable to form retention grooves in cases of wedge-shaped teeth defects that exceed 1.5 mm. In case of restoration of subgingival wedge-shaped defects of teeth of small height it is recommended to create one retention groove on the gingival or incisal planes of a carious cavity due to significant inconveniences, and sometimes impossibility of formation of traditionally located retention grooves.

Effect of pipe expansion on the redistribution of residual stresses after molding

2020 ◽  
Vol 10 (2) ◽  
pp. 122-126
Author(s):  
Nikolay A. Makhutov ◽  
◽  
Dmitry A. Neganov ◽  
Eugeny P. Studenov ◽  
◽  
...  
Keyword(s):  
Residual Stresses ◽  
Strain Distribution ◽  
Strain State ◽  
Stress And Strain ◽  
Cylindrical Shape ◽  
Pipe Material ◽  
Pipe Expansion ◽  
Calculation Results ◽  
Residual Deformations ◽  
Stress And Strain Distribution

In the factory, pipes for trunk oil and oil product pipelines are obtained by molding and welding. To ensure a cylindrical shape and reduce technological residual stresses, expansion technology is used. Pipe expansion causes a significant change in the values of residual deformations and stresses. The article presents both the calculation results and graphs regarding stress and strain distribution during bending of the stock and their redistribution after expansion. Based on the calculation results, the final total values of residual stresses and residual deformations caused by bending and expansion were stated to be important components of the stress-strain state observed in pipelines being operated under cyclic loading, as well as those used in assessing how degradation affects the ductility of the pipe material. These factors were concluded as being reasonably taken into account when performing verification calculations regarding long-running pipelines if, based on their diagnostics and analysis, their state does not meet modern strength requirements.

Strain, Stress, and Magnetic Surfaceanisotropy of Epitaxial FE(110)/MO (110) Multilayers

1993 ◽  
Vol 317 ◽  
Author(s):  
R.M. Osgood ◽  
B.M. Clemens ◽  
R.L. White ◽  
S. Brennan
Keyword(s):  
Strain State ◽  
Single Layer ◽  
Grazing Incidence ◽  
Magnetic Surface ◽  
Stress And Strain ◽  
Surface Anisotropy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plane Direction ◽  
Strain Stress

ABSTRACTGrazing incidence and asymmetric X-ray diffraction were used to measure the stress and strain state of Fe(110)/Mo(110) Multilayers. The highest stress in the Fe constituent of the multilayer was along the [110] in-plane direction and was due to interaction with the substrate. The Magnetic anisotropy of the Fe Multilayer constituent was measured and the magnetic surface anisotropy, which favored in-plane [001] magnetization, was deduced. In contrast, the magnetic surface anisotropy of a single layer of Fe on W preferred in-plane [110] magnetization, in agreement with the Néel Model.

Near Surface Research and Excitation Horizon Prediction Based on Old River Course of Xiaoqing River in Shan Dong

2013 ◽  
Vol 664 ◽  
pp. 94-98
Author(s):  
Guang De Zhang
Keyword(s):  
Seismic Data ◽  
Practical Significance ◽  
Cone Penetration ◽  
Surface Deposition ◽  
Near Surface ◽  
Sedimentary Characteristics ◽  
The Difference ◽  
Exploration Area ◽  
Data Requirements ◽  
Static Cone Penetration Test

Following deepened exploration and development in Shengli exploration area, seismic data requirements are also getting higher and higher. However, in recent years the difference of Xiaoqing river on both sides have made us know that the importance of this problem. In view of the above, this task is aimed at quaternary shallow of old river course within Xiaoqing River. Our analysis of lithology and sedimentary characteristics are using static cone penetration test and rock core exploration method, and we want to reappear near surface deposition of old river course within Xiaoqing River. The research is close combined with the exploration demand and theoretical study, so it has important theoretical and practical significance.

Towards a Better Understanding of Modeling Feasibility Robustness in Engineering Design

1999 ◽  
Vol 122 (4) ◽  
pp. 385-394 ◽  
Author(s):  
Xiaoping Du ◽  
Wei Chen
Keyword(s):  
Robust Design ◽  
Optimization Problems ◽  
Practical Significance ◽  
Engineering Practice ◽  
Probabilistic Optimization ◽  
Importance Sampling Method ◽  
Feasibility Evaluation ◽  
Feasibility Robustness ◽  
Computationally Intensive ◽  
Six Sigma Approach

In robust design, it is important not only to achieve robust design objectives but also to maintain the robustness of design feasibility under the effect of variations (or uncertainties). However, the evaluation of feasibility robustness is often a computationally intensive process. Simplified approaches in existing robust design applications may lead to either over-conservative or infeasible design solutions. In this paper, several feasibility-modeling techniques for robust optimization are examined. These methods are classified into two categories: methods that require probability and statistical analyses and methods that do not. Using illustrative examples, the effectiveness of each method is compared in terms of its efficiency and accuracy. Constructive recommendations are made to employ different techniques under different circumstances. Under the framework of probabilistic optimization, we propose to use a most probable point (MPP) based importance sampling method, a method rooted in the field of reliability analysis, for evaluating the feasibility robustness. The advantages of this approach are discussed. Though our discussions are centered on robust design, the principles presented are also applicable for general probabilistic optimization problems. The practical significance of this work also lies in the development of efficient feasibility evaluation methods that can support quality engineering practice, such as the Six Sigma approach that is being widely used in American industry. [S1050-0472(00)00904-1]

scholarly journals Global metabolomic and lipidomic analysis reveals the potential mechanisms of hemolysis effect of Ophiopogonin D and Ophiopogonin D' in vivo

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Huan-Hua Xu ◽  
Zhen-Hong Jiang ◽  
Cong-Shu Huang ◽  
Yu-Ting Sun ◽  
Long-Long Xu ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Principal Component ◽  
Partial Least Square ◽  
Least Square ◽  
Practical Significance ◽  
Plasma Metabolites ◽  
Active Components ◽  
The Difference

Abstract Background OPD and OPD' are the two main active components of Ophiopogon japonicas in Shenmai injection (SMI). Being isomers of each other, they are supposed to have similar pharmacological activities, but the actual situation is complicated. The difference of hemolytic behavior between OPD and OPD' in vivo and in vitro was discovered and reported by our group for the first time. In vitro, only OPD' showed hemolysis reaction, while in vivo, both OPD and OPD' caused hemolysis. In vitro, the primary cause of hemolysis has been confirmed to be related to the difference between physical and chemical properties of OPD and OPD'. In vivo, although there is a possible explanation for this phenomenon, the one is that OPD is bio-transformed into OPD' or its analogues in vivo, the other one is that both OPD and OPD' were metabolized into more activated forms for hemolysis. However, the mechanism of hemolysis in vivo is still unclear, especially the existing literature are still difficult to explain why OPD shows the inconsistent hemolysis behavior in vivo and in vitro. Therefore, the study of hemolysis of OPD and OPD' in vivo is of great practical significance in response to the increase of adverse events of SMI. Methods Aiming at the hemolysis in vivo, this manuscript adopted untargeted metabolomics and lipidomics technology to preliminarily explore the changes of plasma metabolites and lipids of OPD- and OPD'-treated rats. Metabolomics and lipidomics analyses were performed on ultra-high performance liquid chromatography (UPLC) system tandem with different mass spectrometers (MS) and different columns respectively. Multivariate statistical approaches such as principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA) were applied to screen the differential metabolites and lipids. Results Both OPD and OPD' groups experienced hemolysis, Changes in endogenous differential metabolites and differential lipids, enrichment of differential metabolic pathways, and correlation analysis of differential metabolites and lipids all indicated that the causes of hemolysis by OPD and OPD' were closely related to the interference of phospholipid metabolism. Conclusions This study provided a comprehensive description of metabolomics and lipidomics changes between OPD- and OPD'-treated rats, it would add to the knowledge base of the field, which also provided scientific guidance for the subsequent mechanism research. However, the underlying mechanism require further research.

Experimental and numerical investigation of Armox 500T armor steel perforation process

2021 ◽  
Vol 70 (1) ◽  
pp. 43-61
Author(s):  
Arkadiusz Popławski
Keyword(s):  
Plastic Deformation ◽  
Strain State ◽  
Numerical Study ◽  
Stress And Strain ◽  
Failure Model ◽  
Modes Of Failure ◽  
State Of Stress ◽  
Computational Code ◽  
Armor Steel ◽  
Plate Perforation

This paper presents the results of an experimental and numerical study of the perforation of Armox 500T armoured steel. The plate perforation was performed with a pneumatic gun using three types of penetrators. Sharp, spherical and blunt penetrators were used. The use of different geometries of penetrators causes the process of perforation and destruction of plates in a different state of stress and strain, which leads to the appearance of three basic modes of failure. Numerical analyses of the perforation process have been carried out using the Ls-Dyna computational code with an advanced constitutive model of the material and the integrated failure model. The obtained experimental and numerical results were analysed and compared. The failure shape, the level of plastic deformation and the parameters of stress and strain state were analysed.

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