Geometric Constants in Plain Cross-Bored Cylinders

2003 ◽  
Vol 125 (4) ◽  
pp. 446-453 ◽  
Author(s):  
J. M. Kihiu ◽  
G. O. Rading ◽  
S. M. Mutuli
Keyword(s):  
Hoop Stress ◽  
Three Dimensional ◽  
Solution Technique ◽  
Thin Shells ◽  
Far Field ◽  
Stress Distributions ◽  
Maximum Hoop Stress ◽  
Thick Shells ◽  
Geometric Constants ◽  
Good Agreement

A three-dimensional FEM computer program was developed to establish the stress distributions and SCFs in thick walled cylinders with flush and nonprotruding plain cross bores under internal pressure. The displacement formulation and eight-noded brick isoparametric elements were used. The Frontal solution technique was used due to the limited computing facilities. In the far field, the FEM stresses and displacements were in good agreement with the through thickness analytical values. The variation of SCF with d was established for various thickness ratios. For k>1.25, the maximum hoop stress occurred away from the crotch corner when d⩽0.2. For k=1.25, the maximum hoop stress occurred away from the crotch corner when d⩽0.15. For k⩾1.75, d was found to be a geometrical constant equal to 0.2 where the k values have a SCF of 2.734. For k<1.75, d was found to be a geometrical constant equal to 0.11 where the k values have a SCF of 2.67. A new categorization of cylinders has been proposed: thin shells, thick shells, and thick cylinders.

Maximum Hoop Stress Evaluation of a Hollow Cylindrical Bulk Superconductor in Field-Cooled Magnetization

2014 ◽  
Vol 792 ◽  
pp. 15-20 ◽  
Author(s):  
Masanori Tsuchimoto
Keyword(s):  
Maxwell Equations ◽  
Hoop Stress ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Bulk Superconductor ◽  
Stress Evaluation ◽  
High Tc ◽  
High Tc Superconductor ◽  
Maximum Hoop Stress ◽  
The Finite Difference Method

Stresses are induced in a bulk high-Tc superconductor (HTS) by field-cooled magnetization. The stress distributions of a hollow cylindrical bulk HTS are numerically studied in the axisymmetric three-dimensional analysis. Shielding current distributions are obtained through a macroscopic numerical simulation with the Maxwell equations and the critical state model. Stress distributions are obtained by using the finite-difference method and iterative calculations. Maximum hoop stress during the field-cooled magnetization is discussed for open and fixed boundary conditions.

Heat and Mass Diffusion Including Shrinkage and Hygrothermal Stress during Drying of Holed Ceramics Bricks

2011 ◽  
Vol 312-315 ◽  
pp. 971-976 ◽  
Author(s):  
J. Barbosa da Silva ◽  
G. Silva Almeida ◽  
W.C.P. Barbosa de Lima ◽  
Gelmires Araújo Neves ◽  
Antônio Gilson Barbosa de Lima
Keyword(s):  
Moisture Content ◽  
Three Dimensional ◽  
Average Moisture Content ◽  
Stress Distributions ◽  
Drying Process ◽  
Convective Boundary ◽  
Volume Method ◽  
Hygrothermal Stress ◽  
Thermo Physical Properties ◽  
Good Agreement

The Aim of this Work Is to Present a Three-Dimensional Mathematical Modelling to Predict Heat and Mass Transport inside the Industrial Brick with Rectangular Holes during the Drying Including Shrinkage and Hygrothermalelastic Stress Analysis. the Numerical Solution of the Diffusion Equation, Being Used the Finite-Volume Method, Considering Constant Thermo-Physical Properties and Convective Boundary Conditions at the Surface of the Solid, it Is Presented and Analyzed. Results of the Temperature, Moisture Content and Stress Distributions, and Drying and Heating Kinetics Are Shown and Analyzed. Results of the Average Moisture Content and Surface Temperature of the Brick along the Drying Process Are Compared with Experimental Data (T = 80.0oC and RH = 4.6 %) and Good Agreement Was Obtained. it Was Verified that the Largest Temperature, Moisture Content and Stress Gradients Are Located in the Intern and External Vertexes of the Brick.

Overstraining of flush plain cross-bored cylinders

2004 ◽  
Vol 218 (2) ◽  
pp. 143-153 ◽  
Author(s):  
J M Kihiu ◽  
G O Rading ◽  
S M Mutuli
Keyword(s):  
Finite Element Method ◽  
Yield Criterion ◽  
Three Dimensional ◽  
Yield Condition ◽  
Solution Technique ◽  
Stress Distributions ◽  
Dimensional Finite Element ◽  
Von Mises ◽  
Three Dimensional Finite Element ◽  
Incremental Theory Of Plasticity

A three-dimensional finite element method computer program was developed to establish the elastic-plastic, residual and service stress distributions in thick-walled cylinders with flush and non-protruding plain cross bores under internal pressure. The displacement formulation and eight-noded brick isoparametric elements were used. The incremental theory of plasticity with a 5 per cent yield condition (an element is assumed to have yielded when the effective stress is within 5 per cent of the material yield stress) and von Mises yield criterion were assumed. The frontal solution technique was used. The incipient yield pressure and the pressure resulting in a 0.3 per cent overstrain ratio were established for various cylinder thickness ratios and cross bore-main bore radius ratios. For a thickness ratio of 2.25 and a cross bore-main bore radius ratio of 0.1, the stresses were determined for varying overstrain and an optimum overstrain ratio of 37 per cent was established. To find the accuracy of the results, the more stringent yield condition of 0.5 per cent was also considered. The benefits of autofrettage were presented and alternative autofrettage and yield condition procedures proposed.

Residual Stress Prediction for Non-Axisymmetric Vessel Penetration Welds

2008 ◽  
Author(s):  
Kazuo Ogawa ◽  
Nobuyoshi Yanagida ◽  
Koichi Saito
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Three Dimensional ◽  
Measurement Data ◽  
Fe Model ◽  
Stress Distributions ◽  
Dimensional Finite Element ◽  
Stress Prediction ◽  
Three Dimensional Finite Element ◽  
Good Agreement

Residual stress distribution in an oblique nozzle jointed to a vessel with J-groove welds was analyzed using a three-dimensional finite element method. All welding passes were considered in a 180-degree finite element (FE) model with symmetry. Temperature and stress were modeled for simultaneous bead laying. To determine residual stress distributions at the welds experimentally, a mock-up specimen was manufactured. The analytical results show good agreement with the experimental measurement data, indicating that FE modeling is valid.

Determination of Stress Intensity Factors for Partial Penetration Axial Cracks in Thin-Walled Cylinders

1986 ◽  
Vol 108 (2) ◽  
pp. 83-86 ◽  
Author(s):  
Weili Cheng ◽  
Iain Finnie
Keyword(s):  
Stress Intensity ◽  
Hoop Stress ◽  
Numerical Solutions ◽  
Stress Distributions ◽  
Intensity Factors ◽  
Axial Crack ◽  
Thin Walled ◽  
Walled Cylinder ◽  
Good Agreement

An approach based on the use of rotation and displacement solutions for a cracked element in plane strain is used to obtain the stress intensity factor for a long axial crack in a thin-walled cylinder. The hoop stress distribution in the cylinder prior to introduction of the crack is arbitrary. Results obtained with this approach are in good agreement with numerical solutions for several hoop stress distributions.

Dimensioning of thick-walled spherical and cylindrical pressure vessels

2017 ◽  
Vol 25 (7) ◽  
pp. 1405-1415 ◽  
Author(s):  
Patrick Schneider ◽  
Reinhold Kienzler
Keyword(s):  
Hoop Stress ◽  
Classical Problem ◽  
Pressure Vessels ◽  
Combined Loading ◽  
Von Mises Stress ◽  
Absolute Maximum ◽  
Stress Distributions ◽  
Extensive Discussion ◽  
Maximum Hoop Stress ◽  
Von Mises

In this contribution, we revisit the rather classical problem of Lamé and provide a novel and easy way to plot the stress distributions and the overall absolute maximum von Mises stress for arbitrary parameters in only two diagrams. We also provide a maximum hoop stress formula for combined loading and an extensive discussion covering the accuracy of dimensioning via the maximum hoop stress instead of the maximum von Mises stress, as well as the accuracy of the classical approximative hoop stress formulas.

External Pressure Loading of Spiral Paper Tubes: Theory and Experiment

1990 ◽  
Vol 112 (2) ◽  
pp. 144-150 ◽  
Author(s):  
T. D. Gerhardt
Keyword(s):  
Hoop Stress ◽  
Tube Wall ◽  
Outer Wall ◽  
External Pressure ◽  
Isotropic Case ◽  
Stress Distributions ◽  
Elasticity Solution ◽  
Maximum Hoop Stress ◽  
Remarkable Agreement ◽  
Walled Cylinder

A closed-form elasticity solution is developed to predict stresses and strains in spiral paper tubes loaded axisymmetrically. No assumptions are made on stress distributions through the tube wall. Thus, the solution is valid for thick-walled tubes. The validity of this solution is established by comparison with experimental results. Measured strains in tubes subjected to external pressure showed remarkable agreement with the elasticity solution. After experimental verification, the elasticity solution is used to examine stress distributions in paper tubes loaded in external pressure. In both paper and isotropic tubes, the hoop stress dominates the other three stresses. However, the hoop stress distribution in paper tubes was radically different from the isotropic case. In paper tubes: (1) hoop stress was concentrated at the outer wall, especially for thicker tubes and (2) maximum hoop stress remained constant as tube thickness was increased. These differences can be attributed to the extremely small modulus in the radial direction of a paper tube. The hoop stress distributions indicate that isotropic, thick-walled cylinder theory is inapplicable for modeling paper tubes.

Lower Bound Net-Section Limit Loads for Circumferential Part-Through Surface Cracked Pipes Under Combined Pressure and Bending

2007 ◽  
Author(s):  
Chang-Kyun Oh ◽  
Yun-Jae Kim ◽  
Jong-Sung Kim ◽  
Te-Eun Jin
Keyword(s):  
Hoop Stress ◽  
Plastic Material ◽  
Three Dimensional ◽  
Limit Load ◽  
Surface Cracks ◽  
Stress Distributions ◽  
Plastic Limit ◽  
Limit Loads ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

This paper provides plastic limit loads of pipes with constant-depth, circumferential part-through surface cracks under combined pressure and bending. A key issue is to postulate discontinuous hoop stress distributions in the net-section. Validity of the proposed limit load solutions are checked against the results from three-dimensional (3-D) finite element (FE) limit analyses using elastic-perfectly plastic material behaviour.

scholarly journals Euler Analysis of the Three-Dimensional Flow Field of a High-Speed Propeller: Boundary Condition Effects

1987 ◽  
Vol 109 (3) ◽  
pp. 332-339 ◽  
Author(s):  
M. Nallasamy ◽  
B. J. Clark ◽  
J. F. Groeneweg
Keyword(s):  
Flow Field ◽  
Boundary Conditions ◽  
High Speed ◽  
Three Dimensional ◽  
Tip Vortex ◽  
Power Coefficient ◽  
Far Field ◽  
Field Boundary ◽  
Nonreflecting Boundary Conditions ◽  
Good Agreement

This paper presents the results of an investigation of the effects of far field boundary conditions on the solution of the three-dimensional Euler equations governing the flow field of a high-speed single rotation propeller. The results show that the solutions obtained with the nonreflecting boundary conditions are in good agreement with experimental data. The specification of nonreflecting boundary conditions is effective in reducing the dependence of the solution on the location of the far field boundary. Details of the flow field within the blade passage and the tip vortex are presented. The dependence of the computed power coefficient on the blade setting angle is examined.

A Free Energy Perturbation Approach to Estimate the Intrinsic Solubilities of Drug-like Small Molecules

2019 ◽  
Author(s):  
Sayan Mondal ◽  
Gary Tresadern ◽  
Jeremy Greenwood ◽  
Byungchan Kim ◽  
Joe Kaus ◽  
...  
Keyword(s):  
Solid State ◽  
Small Molecules ◽  
Three Dimensional ◽  
Aqueous Solubility ◽  
Computational Approach ◽  
Free Energy Perturbation ◽  
Perturbation Approach ◽  
Energy Perturbation ◽  
State Form ◽  
Good Agreement

<p>Optimizing the solubility of small molecules is important in a wide variety of contexts, including in drug discovery where the optimization of aqueous solubility is often crucial to achieve oral bioavailability. In such a context, solubility optimization cannot be successfully pursued by indiscriminate increases in polarity, which would likely reduce permeability and potency. Moreover, increasing polarity may not even improve solubility itself in many cases, if it stabilizes the solid-state form. Here we present a novel physics-based approach to predict the solubility of small molecules, that takes into account three-dimensional solid-state characteristics in addition to polarity. The calculated solubilities are in good agreement with experimental solubilities taken both from the literature as well as from several active pharmaceutical discovery projects. This computational approach enables strategies to optimize solubility by disrupting the three-dimensional solid-state packing of novel chemical matter, illustrated here for an active medicinal chemistry campaign.</p>

Sign in / Sign up

Export Citation Format

Share Document