scholarly journals Stability Numbers for Unsupported Conical Excavations in Multi-Layered Cohesive Soils

2020 ◽  
Vol 10 (24) ◽  
pp. 8839
Author(s):  
Kwangwoo Lee ◽  
Junyoung Ko ◽  
Hyunsung Lim ◽  
Joon Kyu Lee
Keyword(s):  
Finite Element ◽  
Rigid Base ◽  
Width Ratio ◽  
Cohesive Soils ◽  
Finite Element Analyses ◽  
Layered Clays ◽  
Wide Range ◽  
Displacement Pattern ◽  
Strength Difference ◽  
Familiar Form

This paper presents the results of a numerical analysis into undrained stability of conical excavation in multi-layered clays. Stability predictions for a wide range of geometric and material combinations are calculated by finite element analyses. The results from the present analysis are expressed in the familiar form of stability numbers reflecting the effect of (1) angle of inclination, (2) depth ratio, which is relative top layer thickness to excavation depth, (3) strength difference between two layers on the rigid base, (4) width ratio, which is excavation height to radius at the bottom of excavation, and (5) thickness ratio, which is the ratio of the excavation height to thickness of soil 1 layers. The obtained stability numbers are compared with existing solutions published in the literature. The failure mechanism in multi-layered clays are also discussed in terms of the displacement pattern.

Tank Car Puncture Analyses for Various Impactors and Impact Conditions

2013 ◽  
Author(s):  
Steven W. Kirkpatrick ◽  
Francisco Gonzalez ◽  
Karl Alexy
Keyword(s):  
Finite Element ◽  
Research Program ◽  
Impact Testing ◽  
Impact Behavior ◽  
Finite Element Analyses ◽  
Damage And Failure ◽  
Wide Range ◽  
Significant Research ◽  
Detailed Simulation ◽  
The Impact

There has been significant research in recent years to analyze and improve the impact behavior and puncture resistance of railroad tank cars. Much of this research has been performed using detailed nonlinear finite element analyses supported by full scale impact testing. This use of detailed simulation methodologies has significantly improved our understanding of the tank impact behaviors and puncture prediction. However, the evaluations in these past studies were primarily performed for a few idealized impact scenarios. This paper describes a research program to evaluate railroad tank car puncture behaviors under more general impact conditions. The approach used in this research program was to apply a tank impact and puncture prediction capability using detailed finite element analyses (FEA). The analysis methodologies apply advanced damage and failure models that were validated by series of material tests under various loading conditions. In this study, the analyses were applied to investigate the tank puncture behaviors for a wide range of impact conditions.

Quantification of Crack Length and Thickness Effects on J-R Curves by Ductile Damage Models

2006 ◽  
Vol 326-328 ◽  
pp. 935-938
Author(s):  
Yoon Suk Chang ◽  
T.R. Lee ◽  
Jae Boong Choi ◽  
Chang Sung Seok ◽  
Young Jin Kim
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Crack Length ◽  
Compact Tension ◽  
Width Ratio ◽  
Fracture Toughness Test ◽  
Finite Element Analyses ◽  
Local Approach ◽  
Damage Models ◽  
Different Thickness

In this paper, the applicability of local approach is examined for SA515 Gr.60 nuclear steel through a series of finite element analyses incorporating modified GTN and Rousselier models as well as fracture toughness tests. To achieve the goal, fracture toughness test data of standard compact tension (CT) specimens are used for calibration of micro-mechanical parameters. Then, from finite element analyses employing the calibrated parameters, fracture resistance (J-R) curves of CT specimens with different crack length to width ratio, with different thickness and with/without 20% side-grooves are predicted. Finally, suitability of the numerically estimated J-R curves was verified by comparison with the corresponding experimental J-R curves.

Asymmetric Shielding in Interfacial Fracture Under In-Plane Shear

1992 ◽  
Vol 59 (2) ◽  
pp. 295-304 ◽  
Author(s):  
K. M. Liechti ◽  
Y. S. Chai
Keyword(s):  
Finite Element ◽  
Crack Initiation ◽  
Crack Opening ◽  
Three Dimensional ◽  
Inelastic Behavior ◽  
Finite Element Analyses ◽  
Plane Shear ◽  
Plastic Dissipation ◽  
Wide Range ◽  
Interference Measurements

The toughness of a glass/epoxy interface was measured over a wide range of mode mixes. A toughening effect was associated with increasing positive and negative inplane shear components. Optical interference measurements of normal crack opening displacements near the crack front and complementary finite element analyses were used to examine near-front behavior during crack initiation. Estimates of the toughening based on plastic dissipation, bulk viscoelastic dissipation, and interface asperity shielding did not fully account for the measured values. The results suggest that the inelastic behavior of the epoxy, frictional, and, perhaps, three-dimensional effects should be considered.

Stress Concentration Factors for Crossbores in Thick Walled Cylinders and Square Blocks

2010 ◽  
Author(s):  
Katsumi Watanabe ◽  
Susumu Terada
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Boundary Conditions ◽  
Finite Element Analyses ◽  
Wide Range ◽  
Section Viii ◽  
Concentration Factors ◽  
Stress Concentration Factors

In this study, finite element analyses were performed to investigate the stress concentration factors around cross-bores in thick walled cylinders and square blocks. As for the results, the stress concentration factors are presented relating the wide range of ratios of the diameters of main and sub bores (DH/DI) to some specific values of the wall ratios (Y). The effects of boundary conditions were also investigated. As these obtained stress concentration factors seems to show some differences from these in Appendix J of ASME Section VIII Div.3 [1], the revisions of these stress concentration factors in Div.3 are proposed.

Stress Categorization Using the Reference Two-Bar Structure

2007 ◽  
Author(s):  
M. M. Hossain ◽  
R. Adibi-Asl ◽  
R. Seshadri
Keyword(s):  
Finite Element ◽  
Pressure Vessel ◽  
Three Dimensional ◽  
Complex Loading ◽  
Finite Element Analyses ◽  
Number Of Components ◽  
Elastic Stresses ◽  
Linear Elastic ◽  
Geometric Configurations ◽  
Wide Range

The ASME Boiler and Pressure Vessel Codes and Standards used for designing pressure vessel and piping provide guidelines to classify the linear elastic stresses into primary, secondary and peak categories. Although these guidelines cover a wide range of pressure components, they are sometimes difficult to apply to the three-dimensional components with complex loading and geometries. The concept of “reference two-bar structure” is used in this paper to categorize the stresses in pressure components and structures, using linear elastic finite element analyses. The method is applied to a number of components and structures from simple to relatively complex geometric configurations. The results compare well with those obtained from commercial finite element codes.

Practical design of holes in steel webs

1988 ◽  
Vol 15 (3) ◽  
pp. 456-469
Author(s):  
Peter G. Buckland ◽  
F. Michael Bartlett ◽  
Ralph D. Watts
Keyword(s):  
Finite Element ◽  
Key Words ◽  
Elastic Analysis ◽  
Finite Element Analyses ◽  
Wide Range ◽  
Plastic Analysis ◽  
Practical Design ◽  
Multiple Holes ◽  
Steel Design ◽  
Small Holes

Solutions are presented for the design of reinforcement for a wide range of holes in steel webs. Methods are derived for situations not covered in available published literature. Both elastic and plastic solutions are given for round holes, either unreinforced or reinforced with doubler or tripler plates. Welds and web stability are considered. A solution is given for small holes and a comparison is made with the recent research. For noncircular holes Vierendeel and finite element analyses are discussed, as well as a plastic analysis of rectangular doubler plates. Five methods of dealing with multiple holes in a web panel are presented, each appropriate for different circumstances: elastic analysis, Vierendeel action, plastic summation, the use of stiffeners for “trussing”, and the powerful “checkerboard” technique. It is found that reliance on the ductility of steel has considerable advantages. Fatigue is considered.The methods are appropriate for square or rectangular web panels with central or noncentral holes subjected to any applied in-plane stresses. Key words: webs, holes, girders, steel, design.

Design of flexure revolute joint based on compliance and stiffness ellipsoids

2021 ◽  
pp. 095441002110169
Author(s):  
Jing Zhang ◽  
Hong-wei Guo ◽  
Juan Wu ◽  
Zi-ming Kou ◽  
Anders Eriksson
Keyword(s):  
Finite Element ◽  
Single Point ◽  
Synthesis Method ◽  
Nonlinear Finite Element ◽  
Finite Element Analyses ◽  
Rotational Stiffness ◽  
Rotational Angle ◽  
Parameterized Model ◽  
Flexure Joints ◽  
Translational Stiffness

In view of the problems of low accuracy, small rotational angle, and large impact caused by flexure joints during the deployment process, an integrated flexure revolute (FR) joint for folding mechanisms was designed. The design was based on the method of compliance and stiffness ellipsoids, using a compliant dyad building block as its flexible unit. Using the single-point synthesis method, the parameterized model of the flexible unit was established to achieve a reasonable allocation of flexibility in different directions. Based on the single-parameter error analysis, two error models were established to evaluate the designed flexure joint. The rotational stiffness, the translational stiffness, and the maximum rotational angle of the joints were analyzed by nonlinear finite element analyses. The rotational angle of one joint can reach 25.5° in one direction. The rotational angle of the series FR joint can achieve 50° in one direction. Experiments on single and series flexure joints were carried out to verify the correctness of the design and analysis of the flexure joint.

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