Development of Analysis Tools for RC Members Subjected to Three-Dimensional Combined Loads

2010 ◽  
Author(s):  
T. Ravi S. Mullapudi ◽  
Ashraf Ayoub
Keyword(s):  
Three Dimensional ◽  
Combined Loads ◽  
Analysis Tools

Harmonic analysis tools for stochastic magnetohydrodynamics equations in Besov spaces

2016 ◽  
Vol 30 (28n29) ◽  
pp. 1640025 ◽  
Author(s):  
Mamadou Sango ◽  
Tesfalem Abate Tegegn
Keyword(s):  
Harmonic Analysis ◽  
Existence Result ◽  
Three Dimensional ◽  
Regularity Result ◽  
Heat Equations ◽  
Analysis Tools ◽  
Large Numbers ◽  
Magnetohydrodynamics Equation ◽  
Stochastic Heat Equations ◽  
Time Existence

We establish a regularity result for stochastic heat equations in probabilistic evolution spaces of Besov type and we use it to prove a global in time existence and uniqueness of solution to a stochastic magnetohydrodynamics equation. The existence result holds with a positive probability which can be made arbitrarily close to one. The work is carried out by blending harmonic analysis tools such as Littlewood–Paley decomposition, Jean–Micheal Bony paradifferential calculus and stochastic calculus. The law of large numbers is a key tool in our investigation. Our global existence result is new in three-dimensional spaces.

scholarly journals Use of Transition Modeling to Enable the Computation of Losses for Variable-Speed Power Turbine

2012 ◽  
Author(s):  
Ali A. Ameri
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Variable Speed ◽  
Accurate Analysis ◽  
Pressure Losses ◽  
Analysis Tools ◽  
Power Turbine ◽  
Wide Range ◽  
Transition Modeling

To investigate the penalties associated with using a variable speed power turbine (VSPT) in a rotorcraft capable of vertical takeoff and landing, various analysis tools are required. Such analysis tools must be able to model the flow accurately within the operating envelope of VSPT. For power turbines low Reynolds numbers and a wide range of the incidence angles, positive and negative, due to the variation in the shaft speed at relatively fixed corrected flows, characterize this envelope. The flow in the turbine passage is expected to be transitional and separated at high incidence. The turbulence model of Walters and Leylek was implemented in the NASA Glenn-HT code to enable a more accurate analysis of such flows. Two-dimensional heat transfer predictions of flat plate flow and two and three dimensional heat transfer predictions on a turbine blade were performed and reported herein. Heat transfer computations were performed because it is a good marker for transition. The final goal is to be able to compute the aerodynamic losses. Armed with the new transition model, total pressure losses for three-dimensional flow of an Energy Efficient Engine (E3) tip section cascade for a range of incidence angles were computed in anticipation of the experimental data. The results obtained form a loss bucket for the chosen blade.

scholarly journals Development of a force–resultant model for spudcan footings on loose sand under combined loads

2016 ◽  
Vol 53 (12) ◽  
pp. 2014-2029 ◽  
Author(s):  
Ning Cheng ◽  
Mark Jason Cassidy
Keyword(s):  
Strain Hardening ◽  
Oil And Gas ◽  
Three Dimensional ◽  
Plasticity Model ◽  
Loose Sand ◽  
Oil And Gas Fields ◽  
Combined Loads ◽  
Centrifuge Tests ◽  
Model Components ◽  
Jack Up

Spudcans are typical foundations used in shallow to moderate-depth water oil and gas fields to support jack-up drilling units. Understanding the behaviour of spudcans under combined loadings is crucial to the overall response of the jack-up structure. This paper presents the development of a strain-hardening plasticity model for a spudcan footing on loose sand. Most of the model components are developed from direct centrifuge observations. The centrifuge tests were performed at an acceleration of 100 times that of the Earth’s gravity on a model spudcan footing subjected to combined vertical, horizontal, and moment loads. All the experiments have been designed and conducted to allow the results to be interpreted with a strain-hardening plasticity framework. Combined loads were applied by using a novel apparatus, which enables independent vertical, horizontal, and rotational movements of the footing. Test results also revealed the existence of a three dimensional sliding surface that intersects with the conventional yield surface. This additional surface has been defined analytically. Retrospective simulation of the experimental data using the plasticity model confirms the model’s capability for use in predicting the behaviour of larger spudcan applications offshore.

scholarly journals Rehabilitation Effect Evaluation of CFRP-Lined Prestressed Concrete Cylinder Pipe under Combined Loads Using Numerical Simulation

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
He Hu ◽  
Fujun Niu ◽  
Tiesheng Dou ◽  
Heng Zhang
Keyword(s):  
Prestressed Concrete ◽  
Three Dimensional ◽  
Steel Cylinder ◽  
Concrete Core ◽  
Concrete Cylinder ◽  
Combined Loads ◽  
Reinforced Polymer ◽  
Dimensional Finite Element ◽  
Prestressed Concrete Cylinder Pipe ◽  
Three Dimensional Finite Element

Prestressed concrete cylinder pipe (PCCP) has been widely used for water transfer and transit projects. However, prestressing wire breaks may result in the rupture of pipes and cause catastrophes. Carbon fiber reinforced polymer (CFRP) liners adhered to the inner concrete core can provide an effective method of internal repair and strengthening of PCCP. To evaluate the rehabilitation effect of CFRP-lined PCCP under combined loads, two contrasting three-dimensional finite element models that investigated the visual cracking of concrete and the yielding of steel cylinders were developed. A conceptual zone was introduced to analyze the different states of the pipe during the phase of wire break. In particular, the complex CFRP-concrete bonded interface was simulated by a cohesive element layer with a bilinear traction-separation response. The results show that CFRP has a good rehabilitation effect on the inner concrete core and steel cylinder but only a slight effect on the outer concrete core, prestressing wire, or mortar. A one-hoop CFRP layer diminishes the area of a yielding steel cylinder of 4.72 m2. In addition, CFRP works more effectively along with an increase in the number of broken wires. This research can provide a basis for strengthening distressed PCCP pipelines.

scholarly journals Understanding Microbialite Morphology Using a Comprehensive Suite of Three-Dimensional Analysis Tools

Astrobiology ◽  
2011 ◽  
Vol 11 (6) ◽  
pp. 509-518 ◽  
Author(s):  
Eric W. Stevens ◽  
Dawn Y. Sumner ◽  
Cara L. Harwood ◽  
James P. Crutchfield ◽  
Bernd Hamann ◽  
...  
Keyword(s):  
Dimensional Analysis ◽  
Three Dimensional ◽  
Analysis Tools

scholarly journals 3D Topology Optimization and Mesh Dependency for Redesigning Locking Compression Plates Aiming to Reduce Stress Shielding

2021 ◽  
Vol 7 (3) ◽  
pp. 339
Author(s):  
A. A. Al-Tamimi
Keyword(s):  
Topology Optimization ◽  
Three Dimensional ◽  
Stress Shielding ◽  
Load Condition ◽  
Metallic Materials ◽  
Metallic Material ◽  
Combined Loads ◽  
Locking Compression Plates ◽  
Strain Energy Minimization ◽  
3D Topology

Current fixation plates for bone fracture treatments are built with biocompatible metallic materials such as stainless steel, titanium, and its alloys (e.g., Ti6Al4V). The stiffness mismatch between the metallic material of the plate and the host bone leads to stress shielding phenomena, bone loss, and healing deficiency. This paper explores the use of three dimensional topology-optimization, based on compliance (i.e., strain energy) minimization, reshaping the design domain of three locking compression plates (four-screw holes, six-screw holes, and eight-screw holes), considering different volume reductions (25, 45, and 75%) and loading conditions (bending, compression, torsion, and combined loads). A finite-element study was also conducted to measure the stiffness of each optimized plate. Thirty-six designs were obtained. Results showed that for a critical value of volume reductions, which depend on the load condition and number of screws, it is possible to obtain designs with lower stiffness, thereby reducing the risk of stress shielding.

Interaction Assessment of Diagonally-Spaced Identical Corrosion Defects and Fully-Aligned Unequal-Sized Corrosion Defects Under Combined Loads

2021 ◽  
Author(s):  
Shulong Zhang ◽  
Wenxing Zhou
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Oil And Gas ◽  
Three Dimensional ◽  
Element Model ◽  
Interaction Effects ◽  
Longitudinal Compression ◽  
Combined Loads ◽  
Corrosion Defects ◽  
The Finite Element Model

Abstract In this study, the interaction effects of closely-spaced corrosion defects on the burst capacity of oil and gas pipelines under combined internal pressure and longitudinal compression are investigated by using parametric three-dimensional elasto-plastic finite element analyses. Full-scale burst tests reported in the literature are used to validate the finite element model. It is observed that the interaction effects of diagonally-spaced defects on the burst capacity is strongly related to the overlapping portion of the defect width or circumferential spacing between the two defects. The analysis results indicate that the strongest interaction between diagonally-spaced defects under combined loads occurs if the defects have zero circumferential separation. The interaction weakens as the defects are more and more overlapped or separated circumferentially. It is also observed that the interaction effect associated with longitudinally- or circumferentially-aligned, unequal-sized corrosion defects is negligible under the internal pressure only or combined loads.

Plastic Deformation Behavior of Mild Steel Along Orthogonal Trilinear Strain Trajectories in Three-Dimensional Vector Space of Strain Deviator

1981 ◽  
Vol 103 (4) ◽  
pp. 287-292 ◽  
Author(s):  
Y. Ohashi ◽  
E. Tanaka
Keyword(s):  
Plastic Deformation ◽  
Mild Steel ◽  
Vector Space ◽  
Three Dimensional ◽  
Dimensional Vector ◽  
Dimensional Vector Space ◽  
History Effects ◽  
Combined Loads ◽  
Plastic Deformation Behavior ◽  
Strain Deviator

An experiment was performed on the plastic deformation of mild steel S15C by applying combined loads to thin-walled tubular specimens so that the deformation developed along orthogonal trilinear strain trajectories in the three-dimensional vector space. Scalar and vectorial history effects on the stress vector σ in the deformation along the third branch are examined for 28 kinds of trajectory combined of various values of an angle θe between the first and third branches and a length sl of the second branch.

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