Monitoring and analysis of the stress and deformation of shaft lining and the influence of freezing tube fracture in deep topsoil

2021 ◽  
pp. 103420
Author(s):  
Wang Yan-sen ◽  
Yang Ran
Keyword(s):  
Shaft Lining ◽  
Stress And Deformation

Stress and Deformation

1996 ◽  
Author(s):  
Gerhard Oertel
Keyword(s):  
Differential Equations ◽  
Mathematical Description ◽  
Finite Strain ◽  
Stress Strain ◽  
Complex Problems ◽  
Vector Algebra ◽  
Stress And Deformation

Students of geology who may have only a modest background in mathematics need to become familiar with the theories of stress, strain, and other tensor quantities, so that they can follow, and apply to their own research, developments in modern, quantitative geology. This book, based on a course taught by the author at UCLA, can provide the proper introduction. Included throughout the eight chapters are 136 complex problems, advancing from vector algebra in standard and subscript notations, to the mathematical description of finite strain and its compounding and decomposition. Fully worked solutions to the problems make up the largest part of the book. With their help, students can monitor their progress, and geologists will be able to utilize subscript and matrix notations and formulate and solve tensor problems on their own. The book can be successfully used by anyone with some training in calculus and the rudiments of differential equations.

scholarly journals Stress and deformation analysis of gob-side pre-backfill driving procedure of longwall mining: a case study

2021 ◽  
Author(s):  
Rui Wu ◽  
Penghui Zhang ◽  
Pinnaduwa H. S. W. Kulatilake ◽  
Hao Luo ◽  
Qingyuan He
Keyword(s):  
Rock Mass ◽  
Stress Distribution ◽  
Coal Seam ◽  
Abutment Pressure ◽  
Longwall Mining ◽  
Vertical Stress ◽  
Floor Level ◽  
Working Face ◽  
Floor Heave ◽  
Stress And Deformation

AbstractAt present, non-pillar entry protection in longwall mining is mainly achieved through either the gob-side entry retaining (GER) procedure or the gob-side entry driving (GED) procedure. The GER procedure leads to difficulties in maintaining the roadway in mining both the previous and current panels. A narrow coal pillar about 5–7 m must be left in the GED procedure; therefore, it causes permanent loss of some coal. The gob-side pre-backfill driving (GPD) procedure effectively removes the wasting of coal resources that exists in the GED procedure and finds an alternative way to handle the roadway maintenance problem that exists in the GER procedure. The FLAC3D software was used to numerically investigate the stress and deformation distributions and failure of the rock mass surrounding the previous and current panel roadways during each stage of the GPD procedure which requires "twice excavation and mining". The results show that the stress distribution is slightly asymmetric around the previous panel roadway after the “primary excavation”. The stronger and stiffer backfill compared to the coal turned out to be the main bearing body of the previous panel roadway during the "primary mining". The highest vertical stresses of 32.6 and 23.1 MPa, compared to the in-situ stress of 10.5 MPa, appeared in the backfill wall and coal seam, respectively. After the "primary mining", the peak vertical stress under the coal seam at the floor level was slightly higher (18.1 MPa) than that under the backfill (17.8 MPa). After the "secondary excavation", the peak vertical stress under the coal seam at the floor level was slightly lower (18.7 MPa) than that under the backfill (19.8 MPa); the maximum floor heave and maximum roof sag of the current panel roadway were 252.9 and 322.1 mm, respectively. During the "secondary mining", the stress distribution in the rock mass surrounding the current panel roadway was mainly affected by the superposition of the front abutment pressure from the current panel and the side abutment pressure from the previous panel. The floor heave of the current panel roadway reached a maximum of 321.8 mm at 5 m ahead of the working face; the roof sag increased to 828.4 mm at the working face. The peak abutment pressure appeared alternately in the backfill and the coal seam during the whole procedure of "twice excavation and mining" of the GPD procedure. The backfill provided strong bearing capacity during all stages of the GPD procedure and exhibited reliable support for the roadway. The results provide scientific insight for engineering practice of the GPD procedure.

scholarly journals Effect of peak stress and deformation history on the dynamic tensile behavior of a dual phase steel

2020 ◽  
Author(s):  
J.P. Escobedo ◽  
A.A.H. Ameri ◽  
M. Gonzales ◽  
R. Miller ◽  
H. Wang ◽  
...  
Keyword(s):  
Dual Phase Steel ◽  
Peak Stress ◽  
Tensile Behavior ◽  
Dual Phase ◽  
Deformation History ◽  
Stress And Deformation

scholarly journals Structural Behavior of Prefabricated Ecological Grid Retaining Walls and Application in a Highway in China

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 746
Author(s):  
Xinquan Wang ◽  
Cong Zhu ◽  
Hongguo Diao ◽  
Yingjie Ning
Keyword(s):  
Retaining Wall ◽  
Contact Point ◽  
Retaining Walls ◽  
Wall Structure ◽  
Soil Arching ◽  
Finite Element Software ◽  
Study Results ◽  
Stress And Deformation ◽  
Asymmetrical Condition ◽  
Construction Efficiency

The retaining wall is a common slope protection structure. To tackle the current lack of sustainable and highly prefabricated retaining walls, an environmentally friendly prefabricated ecological grid retaining wall with high construction efficiency has been developed. Due to the asymmetrical condition of the project considered in this paper, the designed prefabricated ecological grid retaining wall was divided into the excavation section and the filling section. By utilizing the ABAQUS finite element software, the stress and deformation characteristics of the retaining wall columns, soil, anchor rods, and inclined shelves in an excavation section, and the force and deformation relationships of the columns, rivets, and inclined shelves in three working conditions in a filling section were studied. The study results imply that the anchor rods may affect the columns in the excavation section and the stress at the column back changes in an M-shape with height. Moreover, the peak appears at the contact point between the column and the anchor rod. The displacement of the column increases slowly along with the height, and the column rotates at its bottom. In the excavation section, the stress of the anchor rod undergoes a change at the junction of the structure. The inclined shelf is an open structure and is very different from the retaining plate structure of traditional pile-slab retaining walls. Its stress distribution follows a repeated U-shaped curve, which is inconsistent with the trend of the traditional soil arching effect between piles, which increases first and then decreases. For the retaining wall structure in the filling section, the numerical simulated vehicle load gives essentially consistent results with the effects of the equivalent filling on the concrete column.

Numerical Analysis on Thermal Deformation of Linear Motor in Chip Mounter

2011 ◽  
Author(s):  
Kang-Woo Joo ◽  
Kwang-Sun Kim ◽  
Jun-Young Kim ◽  
Hee-Rak Beom
Keyword(s):  
Thermal Deformation ◽  
Linear Motor ◽  
Ball Screw ◽  
Heat Transfer Analysis ◽  
Semiconductor Chip ◽  
Research Activities ◽  
And Performance ◽  
Stress And Deformation ◽  
Electro Magnetic ◽  
Semiconductor Chips

In the semiconductor chip mounting process, the size of semiconductor chips is decreasing, while the number of mounting the chips per time are increasing, and this trend is being accelerated. The research activities to develop the chip mounters, which are able to mount rapidly and accurately, have been needed in the industry. With this background, the linear motor in the chip mounters has been an important part. The electro-magnetic type linear motor has many advantages such as direct linear reciprocating motion being compared with the rotary motor and the ball screw type linear motor. However, the electro-magnetic linear motor has thermal problems. These problems affect life and performance of motor and bring out the other problems such as thermal stress and deformation. The heat transfer analysis is difficult to solve thermal problems because the moving and fixed parts coexist. The trial & error methods have been therefore used under majority of cases. In this paper, we investigated the thermal deformation problems of linear motor in a chip mounter and the optimized parameters to design the motion parts of electro-magnetic linear motor were obtained.

Investigation of Strength and Dynamic Characteristics for the Rolling Mill

2013 ◽  
Vol 706-708 ◽  
pp. 1405-1408
Author(s):  
Xi Ping Guo ◽  
Shuang Zhou
Keyword(s):  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Rolling Mill ◽  
Maximum Stress ◽  
Weak Link ◽  
Deformation Analysis ◽  
Vibration Model ◽  
Strength And Stiffness ◽  
Stress And Deformation ◽  
Diagram Analysis

Stress and deformation analysis of 950 mill housing was done by means of ANSYS to calculate the maximum stress and deformation. Strength and stiffness of the mill roll were checked to meet requirements. Carries on the modal analysis to the rolling-mill housing, obtains its first 10 steps the natural frequency and the mode of vibration, through the vibration model diagram analysis frame of the weak link,and it is significant for similar mill housing designs.

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