Corner loading and curling stress analysis for concrete pavements — an alternative approach

2002 ◽  
Vol 29 (4) ◽  
pp. 576-588 ◽  
Author(s):  
Ying-Haur Lee ◽  
Ying-Ming Lee ◽  
Shao-Tang Yen
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Projection Pursuit ◽  
Structural Response ◽  
Concrete Pavements ◽  
Finite Element Program ◽  
Response Characteristics ◽  
Wide Range ◽  
Bending Stresses ◽  
Wheel Loading

Since corner breaks are one of the major structural distresses in jointed concrete pavements, this research study mainly focuses on the determination of the critical bending stresses at the corner of the slab due to the individual and combination effects of wheel loading and thermal curling. A well-known slab-on-grade finite element program (ILLI-SLAB) was used for the analysis. The structural response characteristics of a slab corner were first investigated. Based on the principles of dimensional analysis, the dominating mechanistic variables were carefully identified and verified. A series of finite element factorial runs over a wide range of pavement designs was carefully selected and conducted. The resulting ILLI-SLAB corner stresses were compared with the theoretical Westergaard solutions, and adjustment factors were introduced to account for this discrepancy. Prediction equations for stress adjustments were developed using a modern regression technique (Projection Pursuit Regression). A simplified stress analysis procedure was proposed and implemented in a user-friendly computer program (ILLISTRS) to facilitate instant stress estimations and practical trial applications.Key words: concrete (rigid) pavements, corner breaks, loading, thermal curling, corner stress.

Corner Stress Analysis of Jointed Concrete Pavements

1996 ◽  
Vol 1525 (1) ◽  
pp. 44-56 ◽  
Author(s):  
Ying-Haur Lee ◽  
Ying-Ming Lee
Keyword(s):  
Finite Element ◽  
Prediction Models ◽  
Projection Pursuit ◽  
Computation Time ◽  
Element Model ◽  
Concrete Pavements ◽  
Finite Element Program ◽  
Bending Stresses ◽  
Stress Prediction ◽  
Jointed Concrete Pavements

Because corner breaks are one of the major structural distresses in jointed concrete pavements, the ILLI-SLAB finite-element program was used to analyze the critical corner stresses of concrete pavements under different loading conditions. Subsequently, the effects of a finite slab size, different gear configurations, a widened outer lane, a tied concrete shoulder, and a second bonded or unbonded layer were considered. Based on the principles of dimensional analysis and experimental designs, the dominating mechanistic variables were carefully identified and verified. The resulting ILLI-SLAB stresses were compared with theoretical Westergaard solutions to develop adjustment (multiplication) factors. A new regression technique (projection pursuit regression) was used to develop prediction models to account for these theoretical differences and to instantly estimate the critical corner stresses. A practical application example illustrating the use of the prediction models was also provided and carefully verified using the ILLI-SLAB program. The research findings can be used practically for various designs and analyses of jointed concrete pavements based on theoretical considerations. Not only can the use of these stress prediction models reduce the possibility of obtaining incorrect results due to the improper use of the finite-element model, but it can also reduce the complicated computation time significantly. Furthermore, the critical bending stresses can be conveniently, accurately, and—best of all—instantly calculated through the use of these stress prediction models.

Foundation Modeling for Jointed Concrete Pavements

2000 ◽  
Vol 1730 (1) ◽  
pp. 34-42 ◽  
Author(s):  
William G. Davids
Keyword(s):  
Finite Element ◽  
Temperature Gradient ◽  
Load Transfer ◽  
Plain Concrete ◽  
Positive Temperature ◽  
Concrete Pavements ◽  
Finite Element Program ◽  
Joint Load ◽  
Foundation Type ◽  
Dense Liquid

Issues related to the finite element modeling of base and subgrade materials under jointed plain concrete pavements are examined. The threedimensional finite element program EverFE, developed in conjunction with the Washington State Department of Transportation, was employed for the analyses. The relevant modeling capabilities of EverFE are detailed, including the ability to model multiple foundation layers, the incorporation of loss of contact between slab and base, and the efficient iterative solution strategies that make large three-dimensional finite element analyses possible on desktop computers. The results of parametric studies examining the effects of foundation type (layered elastic and dense liquid) and properties on the response of jointed plain concrete pavements subjected to axle and thermal loads are presented. Special attention is paid to the interactions between joint load transfer effectiveness and foundation type, and joint load transfer is shown to change significantly with different foundation models and properties. A consideration of simultaneous thermal and axle loadings indicates that the effect of foundation type and properties on critical slab stresses caused by edge loading and a positive temperature gradient is relatively small. However, the slab response is quite sensitive to foundation type for a combined negative temperature gradient and corner loading. On the basis of these results, use of an equivalent dense liquid foundation modulus in mechanistic rigid pavement analysis or design is not recommended when stiff base layers are present.

Finite-Element Simulation and Analysis on High Velocity Impact Damage of Aircraft Panel Structure

2007 ◽  
Vol 353-358 ◽  
pp. 1033-1036
Author(s):  
Shu Lin Li ◽  
Man Yi Hou
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
High Velocity ◽  
Equations Of State ◽  
Impact Damage ◽  
Simulation Models ◽  
Finite Element Program ◽  
Contact Algorithm ◽  
Response Characteristics ◽  
Element Simulation

The finite-element simulation models of the projectile and the discrete rod impacting to the aircraft panel structure in high velocity are established according to some experiment projects. Based on dynamic finite-element Program, the forming of impact damage in the panel structure is simulated. Through comparing the simulation results of damage pattern and size in the panel to the experiment results, the reliability of the material models and equations of state and contact algorithm used in the simulations is testified. Take the simulation of projectile vertically impacting to the panel as example, the aircraft panel structure response characteristics are analyzed briefly based on the results including the displacement of typical node in the panel, the stress course of one element and the energy change of the panel.

scholarly journals NONLINEAR FINITE ELEMENT ANALYSIS OF DAMAGED AND STRENGTHENED REINFORCED CONCRETE BEAMS

2014 ◽  
Vol 20 (2) ◽  
pp. 201-210 ◽  
Author(s):  
Muharrem Aktas ◽  
Yusuf Sumer
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Structural Response ◽  
Experimental Tests ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Element Analysis ◽  
Finite Element Program ◽  
Moment Capacity

Bending test of seven reinforced concrete beams are modeled in finite element program to validate the modeling strategies by comparing the structural response of the beams. Three beams in the set are pre-damaged and strengthened with fiber reinforced composites before the bending tests. Cracks are implemented into the model by inserting geometrical discontinuities to represent the pre-damaged beams. Parametric variables such as crack width, length and interval are chosen to simulate different pre-damage levels. Once the proposed modeling strategies are validated by real experimental tests then 196 finite element models are created to study the effects of pre-damage levels on the moment capacity of reinforced concrete beams repaired with CFRP. Results indicate that inclusion of pre-damage levels by means of cracks into the cross sections have significant effect on beams moment capacity.

Implementation of a Finite Element Model for Gear Stress Analysis Based on Tie-Surface Constraints and Its Validation Through the Hertz's Theory

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Ignacio Gonzalez-Perez ◽  
Alfonso Fuentes-Aznar
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Stress Analysis ◽  
Element Model ◽  
Gear Drive ◽  
Bearing Contact ◽  
Stress Maximum ◽  
Bending Stresses ◽  
Gear Drives ◽  
Surface Constraints

A new finite element model for stress analysis of gear drives is proposed. Tie-surface constraints are applied at each tooth of the gear model to obtain meshes that can be independently defined: a finer mesh at contact surfaces and fillet and a coarser mesh in the remaining part of the tooth. Tie-surface constraints are also applied for the connection of several teeth in the model. The model is validated by application of the Hertz's theory in a spiral bevel gear drive with localized bearing contact and by observation of convergency of contact and bending stresses. Maximum contact pressure, maximum Mises stress, maximum Tresca stress, maximum major principal stress, and loaded transmission errors are evaluated along two cycles of meshing. The effects of the boundary conditions that models with three, five, seven, and all the teeth of the gear drive provide on the above-mentioned variables are discussed. Several numerical examples are presented.

scholarly journals Design and Stress Analysis of Low-Noise Adjusted Bearing Contact Spiral Bevel Gears

2002 ◽  
Vol 124 (3) ◽  
pp. 524-532 ◽  
Author(s):  
Alfonso Fuentes ◽  
Faydor L. Litvin ◽  
Baxter R. Mullins ◽  
Ron Woods ◽  
Robert F. Handschuh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Computational Procedure ◽  
Low Noise ◽  
Element Analysis ◽  
Bearing Contact ◽  
Bending Stresses ◽  
Analysis Computer ◽  
Spiral Bevel

An integrated computerized approach for design and stress analysis of low-noise spiral bevel gear drives with adjusted bearing contact has been developed. The computational procedure is an iterative process requiring four separate steps that provide: (a) a parabolic function of transmission errors that is able to reduce the effect of errors of alignment, and (b) reduction of the shift of bearing contact caused by misalignment. Application of finite element analysis permits the contact and bending stresses to be determined and the formation of the bearing contact to be investigated. The design of finite element models and boundary conditions is automated and does not require intermediate CAD computer programs. A commercially available finite element analysis computer program with contact capability is used to conduct the stress analysis. The theory developed is illustrated with numerical examples.

Determining track-induced lateral thermal expansion forces on a curved railway track

2021 ◽  
pp. 095440972199531
Author(s):  
Jubair A Musazay ◽  
Allan M Zarembski ◽  
Joseph W Palese
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Expansion ◽  
Stress Analysis ◽  
Railway Track ◽  
Thin Wall ◽  
Element Analysis ◽  
Thermally Induced ◽  
Wide Range ◽  
Research Studies

This research studies the development of lateral thermal expansion forces on a curved railway track. The geometric alignment of a railway right of way often requires railway tracks to be curved. This curvature which is usually defined by the radius of curvature or degree of curvature represents a higher level of complexity in the track’s analysis and design process. Particularly, presence of curvature on the track introduces multiple sources of force in the lateral (radial) direction, including, but not limited to, lateral thermal expansion, lateral wheel/rail forces due to centrifugal action, lateral components of vertical loads, bogie hunting and nosing effects of locomotives, and vehicle curving dynamics. Some of these forces are well understood such as centrifugal forces while some are not as well understood, such as lateral thermal expansion forces. To bridge this gap, this research studies the development of track-induced lateral thermal expansion forces on a curved railway track. In this research, the curved track is assumed to be an arbitrary arc section of a circular track and is modeled as an equivalent idealized circular ring for analysis. Owing to its importance, three analytical methods are used to include: 1) Timoshenko thermoelastic stress analysis in cylindrical coordinate system, 2) mechanics of thin wall cylinders and 3) adaptation of a variational calculus formulation method from a previous comparable study. A fourth analysis approach is also introduced using a commercially available finite element analysis package. The results of these analyses are compared through a wide range of parametric studies and are then validated by the finite element analysis. The results of this study showed that the several methods presented in this paper, could be used to approximate thermally induced expansion behavior (pre-buckling) on a curved railway track. While all three techniques are effective, the Timoshenko stress analysis method appears to be the most suitable as it is a direct method that examines the stress build up from the element level and takes into account additional material properties, such as the Poisson effect. The research resulted in a methodology for determining load transfer from thermally induced forces in curved railroad track to the fastener and supporting structure.

Further Developments in Applying the Finite Element Method to the Calculation of Temperature Distributions in Machining and Comparisons With Experiment

1983 ◽  
Vol 105 (3) ◽  
pp. 149-154 ◽  
Author(s):  
M. G. Stevenson ◽  
P. K. Wright ◽  
J. G. Chow
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Temperature Fields ◽  
The Finite Element Method ◽  
Finite Element Program ◽  
Temperature Distributions ◽  
Wide Range ◽  
Metal Machining ◽  
Element Program ◽  
Element Method

The finite element program developed in previous work [1] for calculating the temperature distributions in the chip and tool in metal machining has been extended in its range of application. Specifically, the program no longer needs a flow field as input and it can accommodate a wide range of shear angle and contact lengths. An important feature of this paper is that temperature fields from the finite element method have been compared with temperatures obtained with a previously described metallographic method [7]. This is the first time these two techniques have been used for the same machining conditions and the comparisons are very good.

Finite-Element Analysis of Portland Cement Concrete Pavements with Cracks

1997 ◽  
Vol 1568 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jeffery R. Roesler ◽  
Lev Khazanovich
Keyword(s):  
Finite Element ◽  
Crack Depth ◽  
Stress Singularity ◽  
Element Model ◽  
Concrete Pavements ◽  
Portland Cement Concrete ◽  
Element Analysis ◽  
Finite Element Program ◽  
Spring Element ◽  
Element Program

It was verified that finite-element modeling could be successfully used to analyze concrete pavements with partial-depth cracks. An existing finite-element program, ILLI-SLAB, was modified (ILSL97) to allow for partial-depth crack analysis. To model a partial-depth crack, a special line spring element was added to the finite-element code. The line spring elements mimic the behavior of a crack by acting as a rotational hinge between two continuous slabs. By using available fracture mechanics techniques, a relationship was derived between the amount of moment load transfer across a crack and the crack depth. This analytical solution was then used to formulate the element stiffness matrix for the line spring element. The deflections predicted by the new finite-element program are correct, but the stresses in the vicinity of the crack tip needed to be corrected to match the stress singularity zone in front of cracks. Several example problems were used to verify the proposed finite-element model, and an example of a typical highway loading condition was analyzed.

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