Ratchet Boundary Determination Using a Noncyclic Method

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
R. Adibi-Asl ◽  
W. Reinhardt
Keyword(s):  
Elastic Moduli ◽  
Load Carrying Capacity ◽  
Structure Model ◽  
Stress Distributions ◽  
Radial Temperature Gradient ◽  
Element Analysis ◽  
Radial Temperature ◽  
Adjustment Procedure ◽  
Boundary Determination ◽  
Load Carrying

A simple and systematic procedure is proposed for shakedown analysis using a combination of linear and nonlinear finite element analysis (FEA). The method can identify the boundary between the shakedown and ratcheting domains directly and does not require a cyclic analysis (noncyclic). The proposed method performs an elastic-plastic FEA to determine the reduction in load carrying capacity due to the cyclic secondary loads. An elastic modulus adjustment procedure is then used to generate statically admissible stress distributions and kinematically admissible strain distributions under the applied primary loads. By modifying the local elastic moduli it is possible to obtain inelastic-like stress redistribution. The method is demonstrated with a “two-bar structure” model based on analytical routine. The analysis is then applied to some typical shakedown problems including the “classical Bree problem,” the “bimaterial cylinder,” and the “plate with a hole subjected to radial temperature gradient.”

The Elastic Modulus Adjustment Procedure (EMAP) for Shakedown

2008 ◽  
Author(s):  
R. Adibi-Asl ◽  
W. Reinhardt
Keyword(s):  
Elastic Modulus ◽  
Elastic Moduli ◽  
Time History ◽  
Structure Model ◽  
Stress Distributions ◽  
Element Analysis ◽  
Shakedown Analysis ◽  
Adjustment Procedure ◽  
Linear Finite Element ◽  
History Analysis

A simple and systematic procedure is proposed for shakedown analysis using combination of linear and non-linear finite element analysis (FEA). The method can identify the boundary between the shakedown and ratcheting domains directly does not require a time history analysis (non-cyclic). The proposed method is based on elastic modulus adjustment procedure (EMAP) and non-cyclic elastic-plastic FEA. The aim of EMAP is to generate statically admissible stress distributions and kinematically admissible strain distributions. By modifying the local elastic moduli it is possible to obtain an inelastic-like stress redistribution. The method is first demonstrated with a two-bar structure model based on analytical routine. The analysis is then applied to some typical shakedown problems including the “classical Bree problem” and the “bi-material cylinder”.

Research on Post-Tensioned Unbonded Prestressed Concrete Hollowed Floor

2011 ◽  
Vol 94-96 ◽  
pp. 1456-1462
Author(s):  
Xiao Hua Yang ◽  
Chao Yang Zhou ◽  
Xue Jun He ◽  
Teng Chen
Keyword(s):  
Prestressed Concrete ◽  
Experimental Studies ◽  
Load Carrying Capacity ◽  
Structure Model ◽  
Test Results ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Direction Parallel ◽  
Load Carrying ◽  
Post Tensioned

In order to study the mechanical behaviors of post-tensioned unbonded prestressed concrete hollowed floors, a 1/4 scale post-tensioned unbonded prestressed reinforced concrete hollow slab-column structure model is used to act uniform distributed load on the floor. The test results showed that the load carrying capacity is enough. The points of maximum displacement are at the centers of slabs. By means of the experimental studies and elastic finite element analysis methods, the results showed that post-tensioned unbonded prestressed concrete hollowed floor presents anisotropy with layout of circular-tubes in one way. In direction parallel to layout of hollowed tubes, the continuity of floor is destruction and bending stiffness of slab is weakened. For studying the deformations of slab, it can still be considered continuous cross-slab in two directions.

Variational Method for Limit Load Analysis of Inhomogeneous Media

2009 ◽  
Author(s):  
R. Adibi-Asl ◽  
R. Seshadri
Keyword(s):  
Carrying Capacity ◽  
Material Properties ◽  
Three Dimensional ◽  
Limit Load ◽  
Load Carrying Capacity ◽  
Element Analysis ◽  
Strain Fields ◽  
Adjustment Procedure ◽  
Load Carrying ◽  
Load Analysis

The load carrying capacity of a body with varying material properties (inhomogeneous) is investigated using the various lower and upper bound limit load multipliers in the context of varational principles originally proposed by Mura and co-workers. In order to evaluate the different limit load multipliers, Elastic Modulus Adjustment Procedure (EMAP) is used to obtain statically admissible stress and kinemattically admissible strain fields at a limit load stage. The proposed upper and lower bound limit load solutions are compared with the results obtained from inelastic finite element analysis (FEA) for several examples with two-dimensional and three-dimensional geometries.

Variational and Classical Methods for Limit Load Analysis of Inhomogeneous Media

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
R. Adibi-Asl ◽  
R. Seshadri
Keyword(s):  
Carrying Capacity ◽  
Variational Principles ◽  
Three Dimensional ◽  
Limit Load ◽  
Load Carrying Capacity ◽  
Element Analysis ◽  
Strain Fields ◽  
Adjustment Procedure ◽  
Load Carrying ◽  
Load Analysis

The load carrying capacity of a component or structure with varying material properties (inhomogeneous) is investigated using various lower- and upper-bound limit load multipliers in the context of variational principles. In order to evaluate the different limit load multipliers, the elastic modulus adjustment procedure is used to obtain statically admissible stress and kinematically admissible strain fields. The proposed upper and lower bound limit load estimates are compared with the results obtained from inelastic finite element analysis for two- and three-dimensional geometries.

Investigation of Burst Pressure in T-Joints With Wall-Thinning by Using FEA

2017 ◽  
Author(s):  
Atsushi Yamaguchi
Keyword(s):  
Carrying Capacity ◽  
Safety Margin ◽  
Pressure Vessels ◽  
Burst Pressure ◽  
Load Carrying Capacity ◽  
Working Pressure ◽  
Element Analysis ◽  
T Joints ◽  
Wall Thinning ◽  
Load Carrying

Boilers and pressure vessels are heavily used in numerous industrial plants, and damaged equipment in the plants is often detected by visual inspection or non-destructive inspection techniques. The most common type of damage is wall thinning due to corrosion under insulation (CUI) or flow-accelerated corrosion (FAC), or both. Any damaged equipment must be repaired or replaced as necessary as soon as possible after damage has been detected. Moreover, optimization of the time required to replace damaged equipment by evaluating the load carrying capacity of boilers and pressure vessels with wall thinning is expected by engineers in the chemical industrial field. In the present study, finite element analysis (FEA) is used to evaluate the load carrying capacity in T-joints with wall thinning. Burst pressure is a measure of the load carrying capacity in T-joints with wall thinning. The T-joints subjected to burst testing are carbon steel tubes for pressure service STPG370 (JIS G3454). The burst pressure is investigated by comparing the results of burst testing with the results of FEA. Moreover, the maximum allowable working pressure (MAWP) of T-joints with wall thinning is calculated, and the safety margin for the burst pressure is investigated. The burst pressure in T-joints with wall thinning can be estimated the safety side using FEA regardless of whether the model is a shell model or a solid model. The MAWP is 2.6 MPa and has a safety margin 7.5 for burst pressure. Moreover, the MAWP is assessed the as a safety side, although the evaluation is too conservative for the burst pressure.

DESIGN AND ANALYSIS OF AN INTEGRATED THREE- BAY THERMOPLASTIC COMPOSITE WINGBOX

2021 ◽  
Author(s):  
VINCENZO OLIVERI ◽  
GIOVANNI ZUCCO ◽  
MOHAMMAD ROUHI ◽  
ENZO COSENTINO ◽  
RONAN O’HIGGINS ◽  
...  
Keyword(s):  
Variable Stiffness ◽  
Thermoplastic Composite ◽  
High Fidelity ◽  
Material System ◽  
Load Carrying Capacity ◽  
Element Analysis ◽  
Single Piece ◽  
Load Carrying ◽  
Post Buckling ◽  
Composite Material System

The design of a multi-part aerospace structural component, such as a wingbox, is a challenging process because of the complexity arising from assembly and integration, and their associated limitations and considerations. In this study, a design process of a stiffeners-integrated variable stiffness three-bay wingbox is presented. The wingbox has been designed for a prescribed buckling and post-buckling performance (a prescribed real testing scenario) and made from thermoplastic composite material system (Carbon-PEEK) with the total length of three meters. The stiffeners and spars are integrated into the top and bottom panels of the wingbox resulting a single-piece blended structure with no fasteners or joints. The bottom skin also has an elliptical cut-out for access purposes. The composite tows are steered around this cutout for strain concentration reduction purposes. The fiber/tow steering in the top skin bays (compression side) has also been considered for improved compression-induced buckling load carrying capacity. The proposed design has been virtually verified via high fidelity finite element analysis.

Finite Element Analysis of the Static Performance of a Self-Slot-Compensating Aerostatic Bearing

2011 ◽  
Vol 199-200 ◽  
pp. 749-753
Author(s):  
Xiao Bo Zuo ◽  
Jian Min Wang ◽  
Chao Liang Guan ◽  
Juan Li
Keyword(s):  
Finite Element ◽  
Reynolds Equation ◽  
Geometric Parameters ◽  
Load Carrying Capacity ◽  
The Finite Element Method ◽  
Aerostatic Bearing ◽  
Element Analysis ◽  
Consistent Condition ◽  
Load Carrying ◽  
Static Performance

The static performance of an aerostatic bearing with angled surface self-slot-compensation is analyzed. The consistent condition was applied to unitize the Reynolds equation of different forms and the finite element method (FEM) was used to solve the equation. The load carrying capacity (LCC) and the stiffness of the bearing was obtained and the influence of the geometric parameters was discussed. It is concluded that this self-compensating aerostatic bearing can achieve a good performance; the geometric parameters of the gap are interactive, and should be rationally matched.

Reliability analysis of wood I-joists

1993 ◽  
Vol 20 (4) ◽  
pp. 564-573 ◽  
Author(s):  
R. O. Foschi ◽  
F. Z. Yao
Keyword(s):  
Reliability Analysis ◽  
Carrying Capacity ◽  
Failure Modes ◽  
Limit State ◽  
Load Carrying Capacity ◽  
Limit States ◽  
Element Analysis ◽  
Strength Limit ◽  
Reliability Method ◽  
Load Carrying

This paper presents a reliability analysis of wood I-joists for both strength and serviceability limit states. Results are obtained from a finite element analysis coupled with a first-order reliability method. For the strength limit state of load-carrying capacity, multiple failure modes are considered, each involving the interaction of several random variables. Good agreement is achieved between the test results and the theoretical prediction of variability in load-carrying capacity. Finally, a procedure is given to obtain load-sharing adjustment factors applicable to repetitive member systems such as floors and flat roofs. Key words: reliability, limit state design, wood composites, I-joist, structural analysis.

A Numerical Investigation of Laterally Loaded Steel Fin Pile Foundations

2020 ◽  
Author(s):  
Te Pei ◽  
Tong Qiu ◽  
Jeffrey A. Laman
Keyword(s):  
Carrying Capacity ◽  
Load Transfer ◽  
Lateral Load ◽  
Steel Plates ◽  
Pile Foundations ◽  
Load Carrying Capacity ◽  
Element Analysis ◽  
Fea Model ◽  
Load Carrying ◽  
Maximum Improvement

Abstract The present study comprehensively evaluates the improvement in lateral load-carrying capacity of steel pipe piles by adding steel plates (fins) at grade level. This configuration of steel fin pile foundations (SFPFs) is effective for applications where high lateral loads are encountered and rapid pile installation is advantageous. An integrated finite element analysis (FEA) was conducted. The FEA utilized an Abaqus model, first developed to account for the nonlinear soil-pile interaction, and then calibrated and validated against well-documented experimental and filed tests in the literature. The validated FEA model was subsequently used to conduct a parametric study to understand the effect of fin geometry on the load transfer mechanism and the response of SFPFs subjected to lateral loading at pile head. The behavior of SFPFs at different displacement levels and load levels was studied. The effect of the relative density of soil on the performance of SFPFs was also investigated. Based on the numerical simulation results, the optimal fin width for maximum improvement in lateral load-carrying capacity was suggested and the underlining mechanism affecting the efficiency of fins was explained.

Numerical Analysis on Loading Capacity of Continuous Composite Slab with Steel Deck

2011 ◽  
Vol 71-78 ◽  
pp. 898-902
Author(s):  
Yuan Qing Wang ◽  
Jong Su Sung ◽  
Yong Jiu Shi
Keyword(s):  
Numerical Analysis ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Element Analysis ◽  
Composite Slab ◽  
Steel Rebar ◽  
Continuous Slab ◽  
Load Carrying ◽  
Negative Moment ◽  
Reinforced Steel

Composite slab with steel sheeting deck is considered a continuous slab when it is under a constructional situation. Nevertheless, many recent researches are focused on simply supported slab. In order to determine the load carrying capacity regarding various rebar ratio on negative moment region, a numerical analysis was carried out by using finite element analysis. The result of analysis shows that the reinforced steel rebar increases load carrying capacity. Moreover, it has shown that the reinforced length of steel rebar also affect the load carrying capacity.

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