FEM analyses of stress and deformation of a flexible inner pressure bolt

The numerical simulation of tube hydropiercing process on a typical tubular component was conducted by employing the FEM code MARC in order to investigate the deformation mechanism of tube hydropiercing. The 3D FEM models have been established in both inward and outward punching operations. Based on the calculation results of the distributions and their changes of stress and deformation, a plastic bending deformation zone in the vicinity of the hole’s edge has been discovered, which differs greatly from that in the conventional sheet metal punching process. Influence of inner pressure on the quality of hydropierced hole was also investigated.

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Techniques for preparing the Lolium perenne coleorhiza for scanning electron microscope evaluation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124239 ◽

1992 ◽

Vol 50 (1) ◽

pp. 766-767

Author(s):

Susan B.G. Debaene ◽

John S. Gardner ◽

Phil S. Allen

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Lolium Perenne ◽

Morphological Study ◽

Root Hairs ◽

Inner Pressure ◽

Water Potentials ◽

Radicle Emergence ◽

Standard Fixation ◽

Scanning Electron

The coleorhiza is a nonvascular sheath that encloses the embryonic radicle in Poaceae, and is generally the first tissue to emerge during germination. Delicate hairlike extensions develop from some coleorhiza cells prior to radicle emergence. Similar to root hairs, coleorhiza hairs are extremely sensitive to desiccation and are damaged by exposure to negative water potentials. The coleorhiza of Lolium perenne is somewhat spherical when first visible, after which a knob forms at a right angle to the caryopsis due to inner pressure from the elongating radicle. This knob increases in length until the radicle finally punctures the coleorhiza. Standard fixation procedures cause severe desiccation of coleorhiza cells and hairs, making morphological study of the coleorhiza difficult. This study was conducted to determine a more successful process for coleorhiza preservation.

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ANALYSIS OF METAL STRESS AND DEFORMATION DISTRIBUTION IN WELD-AFFECTED ZONES AT MAIN GAS PIPELINES

Austrian Journal of Technical and Natural Sciences ◽

10.29013/ajt-18-9.10-23-28 ◽

2018 ◽

pp. 23-28

Author(s):

D. O. Bukleshev ◽

I. A. Sumarchenkova ◽

I. I. Buzuyev

Keyword(s):

Metal Stress ◽

Gas Pipelines ◽

Deformation Distribution ◽

Stress And Deformation

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Stress and Deformation

10.1093/oso/9780195095036.001.0001 ◽

1996 ◽

Cited By ~ 1

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.

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

International Journal of Coal Science & Technology ◽

10.1007/s40789-021-00460-2 ◽

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.

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

10.1063/12.0000820 ◽

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

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The formation of a stress and deformation field by failure of the coal by explosion of a borehole charge (computer simulation)

10.1063/5.0034404 ◽

2020 ◽

Author(s):

I. E. Shipovskii ◽

V. A. Trofimov

Keyword(s):

Computer Simulation ◽

Deformation Field ◽

Borehole Charge ◽

Stress And Deformation

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

Symmetry ◽

10.3390/sym13050746 ◽

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.

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Numerical Analysis on Thermal Deformation of Linear Motor in Chip Mounter

Volume 6: Fluids and Thermal Systems; Advances for Process Industries, Parts A and B ◽

10.1115/imece2011-63611 ◽

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.

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