Finite Element Analyses of Circumferential Cracks in Thin-Walled Cylinders: T-Stress Solutions

2006 ◽  
Author(s):  
Timothy Lewis ◽  
Xin Wang ◽  
Robert Bell
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fracture Mechanics ◽  
Fracture Analysis ◽  
Finite Element Analyses ◽  
The Finite Element Method ◽  
T Stress ◽  
Bending Loads ◽  
Pipe Radius ◽  
Thin Walled

The elastic T-stress is a parameter used to define the level of constraint at a crack tip. It is important to provide T-stress solutions for practical geometries in order to apply the constraint-based fracture mechanics methodology. In the present paper, T-stress solutions are provided for circumferential through-wall cracks in thin-walled cylinders. Cylinders with a circumferential through-wall crack were analyzed using the finite element method. Three cylinder geometries were considered; defined by the pipe radius (R) to wall thickness (t) ratios: R/t = 5, 10, and 20. The T-stress was obtained at eight crack lengths (θ/π = 0.0625, 0.1250, 0.1875, 0.2500, 0.3125, 0.3750, 0.4375, and 0.5000) for remote tension and remote bending loads. These results are suitable for constraint-based fracture analysis for cylinders with circumferential cracks.

Improving the honing accuracy of the holes of stepped thin-walled cylinders

2021 ◽  
pp. 49-54
Author(s):  
V.A. Ogorodov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cutting Forces ◽  
Software Package ◽  
The Finite Element Method ◽  
Radial Forces ◽  
Thin Walled ◽  
Hole Machining ◽  
Deform 3D ◽  
Walled Cylinder

Different ways of fixing of stepped thin-walled cylinders during honing are analyzed. The conditions for increasing the accuracy of hole machining are determined on the basis of unevenness of cylinder deformations from clamping forces and radial forces simulating cutting forces. The studies used the finite element method and the DEFORM-3D V6.1 software package. Keywords: honing, stepped thin-walled cylinder, hole, accuracy, fixing method, deformation, unevenness, DEFORM-3D V6.1 software package. [email protected]

Research on Machining Accuracy in Milling Ti6Al4V Thin-Walled Component with Paraffin Reinforcement

2012 ◽  
Vol 268-270 ◽  
pp. 504-509
Author(s):  
Biao Gao ◽  
Jie Sun ◽  
Jian Feng Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Machining Accuracy ◽  
The Finite Element Method ◽  
Technical Problems ◽  
Low Stiffness ◽  
Thin Walled ◽  
Element Method

According to the technical problems such as low stiffness vibration and dimension error in milling Ti6Al4V thin-walled component, the manufacturing with paraffin reinforcement is studied. Firstly, paraffin formula for milling thin-walled component is researched. Secondly, applying the finite element method (FEM) to predict the deformation of machining with paraffin reinforcement and the corresponding milling experiments is done to check the the validity of the model. Finally, the influences of machining accuracy about different paraffin formulas for the same component are obtained. This study supplies support for the research of paraffin formula which are based on reducing the distortion of workpiece.

Safety Margin Characterization for In-Service Pressure Vessels Containing Crack Defects

2014 ◽  
Vol 607 ◽  
pp. 717-720
Author(s):  
Si Jian Lin ◽  
Wei Long ◽  
Da Qing Tian
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fracture Mechanics ◽  
Safety Margin ◽  
Assessment Method ◽  
Pressure Vessels ◽  
Residual Lifetime ◽  
The Finite Element Method ◽  
Failure Path ◽  
Failure Assessment

It’s significant and necessary to assess the safety of the in-service pressure vessels containing crack defects, and there are so many methods that can do, for example, the finite element method and probabilistic fracture mechanics assessment method. However, knowing the safety of the pressure vessels containing crack defects is not enough. For the residual lifetime reason, we are eager to get the safety margin of the pressure vessels. That is how secure they are. Aiming at this problem, we put forward the concept of failure path based on the Failure Assessment Diagram (FAD) and fracture mechanics to help to characterize safety margin. Facts proved that this method was original and useful which can provide a new way in solving the residual lifetime assessment problem of the in-service pressure vessels containing crack defects.

Design of a 33-Knot Aluminum Catamaran Ferry

2000 ◽  
Vol 37 (02) ◽  
pp. 88-99
Author(s):  
R. G. Latorre ◽  
P. D. Herrington
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Speed ◽  
Frame Structure ◽  
Test Results ◽  
Finite Element Analyses ◽  
The Finite Element Method ◽  
Floating Frame ◽  
Good Agreement ◽  
Panel Design

This paper presents the results of an investigation on the suitability of using hull panels with alternating fixed and floating frames for a 30–40 knot aluminum catamaran ferry. A prototype 4.6 m × 1.8 m bottom hull panel with alternating frames is analyzed numerically and physically tested. The corresponding finite-element analyses and test results are in good agreement. The results show that the floating frame hull panel design is a feasible structure for an aluminum catamaran. The floating frame structure was then used for a 33-knot, 250-passenger aluminum catamaran ferry designed to meet the ABS High Speed Craft rules. A midship section of the catamaran hull was analyzed using the finite-element method. Catamaran weight estimates, heave and pitch motions, and powering estimates are also provided. The results show that the alternating floating frame structure was within the ABS rules stress allowables.

Application of the Finite Element Method to Linear Elastic Fracture Mechanics

1991 ◽  
Vol 44 (10) ◽  
pp. 447-461 ◽  
Author(s):  
Leslie Banks-Sills
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Displacement Field ◽  
Three Dimensional ◽  
Linear Elastic Fracture Mechanics ◽  
The Finite Element Method ◽  
Linear Elastic ◽  
Elastic Fracture

Use of the finite element method to treat two and three-dimensional linear elastic fracture mechanics problems is becoming common place. In general, the behavior of the displacement field in ordinary elements is at most quadratic or cubic, so that the stress field is at most linear or quadratic. On the other hand, the stresses in the neighborhood of a crack tip in a linear elastic material have been shown to be square root singular. Hence, the problem begins by properly modeling the stresses in the region adjacent to the crack tip with finite elements. To this end, quarter-point, singular, isoparametric elements may be employed; these will be discussed in detail. After that difficulty has been overcome, the stress intensity factor must be extracted from either the stress or displacement field or by an energy based method. Three methods are described here: displacement extrapolation, the stiffness derivative and the area and volume J-integrals. Special attention will be given to the virtual crack extension which is employed by the latter two methods. A methodology for calculating stress intensity factors in two and three-dimensional bodies will be recommended.

scholarly journals Analysis of Contact Deformations in Support Systems Using Roller Prisms

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2644
Author(s):  
Krzysztof Nozdrzykowski ◽  
Zenon Grządziel ◽  
Paweł Dunaj
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Contact Theory ◽  
Finite Element Analyses ◽  
The Finite Element Method ◽  
Hertz Contact ◽  
Contact Points ◽  
Calculation Results ◽  
Reaction Forces ◽  
Shaft Journal

This article presents the results of finite element analyses of the influence of reaction forces on stresses and strains at the contact points of the rollers of prism supports with cylindrical surfaces of the main journals of large-sized crankshafts. The analyses of strains and stresses, as well as the depth of their occurrences, in the case of the shaft journal and support rollers were carried out using Hertz contact theory and the finite element method. These calculation results proved to be highly consistent. Additionally, they provide a basis for stating that, in the case under consideration, permanent deformations do not significantly affect the values of the measured geometrical deviations nor the profile forms of the supported main crankshaft journals.

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