An Experimental Study on the Performance of Fixed-End Supported PFRP Channel Beams under Flexure

2013 ◽  
Vol 702 ◽  
pp. 31-36 ◽  
Author(s):  
Jaksada Thumrongvut ◽  
Sittichai Seangatith
Keyword(s):  
Shear Deformation ◽  
Beam Theory ◽  
Beam Equation ◽  
Vertical Deflection ◽  
Cross Sectional ◽  
Modes Of Failure ◽  
Theory Equation ◽  
Flexural Torsional Buckling ◽  
Fixed End ◽  
Structural Behaviors

The experimental investigation on the fixed-end supported PFRP channel beams subjected to three-point loading is presented. The objectives of this study are to evaluate the effects of the span on the structural behaviors, the critical buckling loads and the modes of failure of the PFRP beams, and to compare the obtained deflections with those obtained from the Timoshenko’s shear deformation beam theory equation in order to check the adequacy of the equation. The beam specimens have the cross-sectional dimensions of 152 43 10 mm with span-to-depth ratio ranging from 16 to 33. A total of twenty-two specimens were performed. Based on the experimental results, it was found that the loads versus mid-span vertical deflection relationships of the beam specimens are linear up to the failure, but the load versus mid-span lateral deflection relationships are geometrically nonlinear. The general modes of failure are the flexural-torsional buckling. Finally, the Timoshenko’s shear deformation beam equation can satisfactorily predict the vertical deflection of the beams within acceptable engineering error.

Experimental Evaluation on Fixed End Supported PFRP Channel Beams and LRFD Approach

2011 ◽  
Vol 105-107 ◽  
pp. 1671-1676 ◽  
Author(s):  
Jaksada Thumrongvut ◽  
Sittichai Seangatith
Keyword(s):  
Experimental Results ◽  
Geometrically Nonlinear ◽  
Vertical Deflection ◽  
Torsional Buckling ◽  
Cross Sectional ◽  
Modes Of Failure ◽  
Flexural Torsional Buckling ◽  
Fixed End ◽  
Structural Behaviors ◽  
Steel Design

In this paper, the experimental results on the fixed end supported PFRP channel beams subjected to three-point loading are presented. The aims of this study are to evaluate the effects of the span (L) on the structural behaviors, the critical buckling moments and the modes of failure of the beams, and to compare the obtained critical buckling moments with those obtained from the modified LFRD steel design equation in order to check the adequacy of the equation. The beam specimens have the cross-sectional dimensions of 76x22x6 mm, with span-to-depth ratio (L/d) ranging from 13 to 52. A total of twenty-six specimens were tested. Based on the experimental results, it was found that the loads versus mid-span vertical deflection relationships of the beams are linear up to the failure. On the contrary, the load versus mid-span lateral deflection relationships are geometrically nonlinear. The general modes of failure are the flexural-torsional buckling. Finally, the modified LFRD equation can satisfactorily predict the critical buckling moment for L/d exceeds 20. However, for L/d < 20, the equation overestimates the critical buckling moment of the beams and more development is needed.

Influences of Concentric and Eccentric Loads on Buckling of Fixed-End Supported Pultruded FRP Channel Beams

2015 ◽  
Vol 1119 ◽  
pp. 721-725 ◽  
Author(s):  
Jaksada Thumrongvut ◽  
Sittichai Seangatith
Keyword(s):  
Research Work ◽  
Geometrically Nonlinear ◽  
Cross Sectional ◽  
Modes Of Failure ◽  
Cross Sectional Dimension ◽  
Center Position ◽  
The Cross ◽  
Flexural Torsional Buckling ◽  
Fixed End ◽  
Structural Behaviors

This paper presents the results of the experimental research performed on the pultruded FRP (PFRP) channel beams subjected to transversely concentric and eccentric loads. The objectives of the research work are to investigate their structural behaviors and to determine the critical buckling moments and modes of failure of the beams with various span-to-depth ratios and eccentricities. Pultruded beams are fixed-end supported at both ends for major and minor-axis flexure. The beam specimens have the cross-sectional dimension of 102×29×6 mm with span-to-depth ratios, ranging from 20 to 40. A total of 40 mono-symmetric section tests were performed. The effects of vertical load position through the cross-section were studied. Also, shear center position with concentric load and three different eccentricities were investigated ranging from 0 to-3e. The specimens were tested to final buckling. Based upon the results of this study, it is found that the load versus mid-span vertical deflection relationships of the beams are linear up to the failure. On the contrary, the load versus mid-span lateral deflection relationships are geometrically nonlinear. The general mode of failure is the flexural-torsional buckling. The eccentrically loaded specimens are failed at buckling loads lower than their concentric counterparts. Overall, the critical buckling moment decreases as the magnitude of eccentricity increases. Additionally, it is noticed thatL/dratio increases, the critical buckling moment is decreased.

scholarly journals Natural Frequency Characteristics of the Beam with Different Cross Sections Considering the Shear Deformation Induced Rotary Inertia

2020 ◽  
Vol 10 (15) ◽  
pp. 5245
Author(s):  
Chunfeng Wan ◽  
Huachen Jiang ◽  
Liyu Xie ◽  
Caiqian Yang ◽  
Youliang Ding ◽  
...  
Keyword(s):  
Shear Deformation ◽  
Cross Sections ◽  
Timoshenko Beam ◽  
High Frequency ◽  
Natural Frequencies ◽  
Beam Theory ◽  
Equation Of Motion ◽  
Timoshenko Beam Theory ◽  
Rotary Inertia ◽  
Cross Sectional

Based on the classical Timoshenko beam theory, the rotary inertia caused by shear deformation is further considered and then the equation of motion of the Timoshenko beam theory is modified. The dynamic characteristics of this new model, named the modified Timoshenko beam, have been discussed, and the distortion of natural frequencies of Timoshenko beam is improved, especially at high-frequency bands. The effects of different cross-sectional types on natural frequencies of the modified Timoshenko beam are studied, and corresponding simulations have been conducted. The results demonstrate that the modified Timoshenko beam can successfully be applied to all beams of three given cross sections, i.e., rectangular, rectangular hollow, and circular cross sections, subjected to different boundary conditions. The consequence verifies the validity and necessity of the modification.

Optimum Design of Vibration Absorbers for Structurally Damped Timoshenko Beams

1998 ◽  
Vol 120 (4) ◽  
pp. 833-841 ◽  
Author(s):  
E. Esmailzadeh ◽  
N. Jalili
Keyword(s):  
Dynamic Response ◽  
Shear Deformation ◽  
Beam Theory ◽  
Optimization Procedure ◽  
Vibration Absorbers ◽  
Rotatory Inertia ◽  
Cross Sectional ◽  
Beam Dynamic ◽  
Practical Applications ◽  
Optimal Dynamic

A procedure in designing optimal Dynamic Vibration Absorbers (DVA) for a structurally damped beam system subjected to an arbitrary distributed harmonic force excitation, is presented. The Timoshenko beam theory is used to assess the effects of rotatory inertia and shear deformation. The method provides flexibility of choosing the number of absorbers depending upon the number of significant modes which are to be suppressed. Uniform cross-sectional area is considered for the beam and each absorber is modeled as a spring-mass-damper system. For each absorber with a selected mass, the optimum stiffness and damping coefficients are determined in order to minimize the beam dynamic response at the resonant frequencies for which they are operated. For this purpose, absorbers each tuned to a different resonance, are used to suppress any arbitrarily number of resonances of the beam. The interaction between absorbers is also accounted for in the analysis. The optimum tuning and damping ratios of the absorbers, each tuned to the mode of concern, are determined numerically by sloving a min-max problem. The Direct Updated Method is used in optimization procedure and the results show that the optimum values of the absorber parameters depend upon various factors, namely: the position of the applied force, the location where the absorbers are attached, the position at which the beam response should be minimized, and also the beam characteristics such as boundary conditions, rotatory inertia, shear deformation, structural damping, and cross sectional geometry. Through the given examples, the feasibility of using proposed study is demonstrated to minimize the beam dynamic response over a broad frequency range. The resulting curves giving the non-dimensional absorber parameters can he used for practical applications, and some interesting conclusions can be drown from the study of them.

Experimental Investigation on Axially Loaded PFRP Compression Members Having Double C-Sections

2014 ◽  
Vol 548-549 ◽  
pp. 510-514
Author(s):  
Sittichai Seangatith ◽  
Jaksada Thumrongvut ◽  
Chanon Chatwiwat
Keyword(s):  
Experimental Investigation ◽  
Research Work ◽  
Test Results ◽  
Cross Sectional ◽  
Modes Of Failure ◽  
Linear Behavior ◽  
Compression Members ◽  
Axially Loaded ◽  
Structural Behaviors ◽  
Structural Plastics

This paper presents the results of an experimental investigation on axially loaded PFRP compression members having double C-sections with pinned-pinned supports. The objectives of this research work are to investigate their structural behaviors and modes of failure and to propose their design equations. The specimens were built from single PFRP C-section, having three cross-sectional dimensions of 76×22×6 mm, 102×29×6 mm and 152×43×10 mm. A total of 42 specimens with slenderness ratios ranging from 21 to 168 were tested. The compression members can be classified as short and long. The short compression members have linear behavior up to 90% to 95% of the ultimate crushing loads. The long compression members have linear behavior up to 80-90% of the flexural buckling loads. By comparing and fitting the test results with the design equations as presented in the ASCE Structural Plastics Design Manual, the design equations that can be used to predict the ultimate compressive stress of the compression members were proposed.

Experimental Investigation on Simply Supported PFRP Channel Beams Subjected to Three-Point Loading

2011 ◽  
Vol 335-336 ◽  
pp. 1321-1326 ◽  
Author(s):  
Sittichai Seangatith ◽  
Jaksada Thumrongvut
Keyword(s):  
Research Work ◽  
Geometrically Nonlinear ◽  
Test Results ◽  
Cross Sectional ◽  
Simply Supported ◽  
Modes Of Failure ◽  
Mode Of Failure ◽  
General Mode ◽  
Flexural Torsional Buckling ◽  
Steel Design

This paper presents the experimental results on the simply supported PFRP channel beams subjected to three-point loading. The objectives of the research work are to investigate the effects of the span (L) of the beams on the behaviors, the critical buckling moments and the modes of failure of the beams, and to compare the obtained critical buckling moments with those obtained from the modified LFRD steel design equation in order to check the adequacy of the equation. The beam specimens have the cross-sectional dimensions of 102×29×6 mm with span-to-depth ratio (L/d) ranging from 20 to 40. A total of ten specimens were tested. Based on the test results, it was found that the load versus mid-span vertical deflection relationships are linear up to the failure, but the load versus mid-span lateral deflection relationships are geometrically nonlinear. The general mode of failure is the flexural-torsional buckling. Finally, the modified LFRD equation can satisfactorily predict the critical buckling moment of the PFRP beams used in this study.

The Influence of Geometric and Material Design Variables on the Free Vibration of Thin-Walled Composite Material Beams

1989 ◽  
Vol 111 (3) ◽  
pp. 290-297 ◽  
Author(s):  
L. C. Bank ◽  
C. H. Kao
Keyword(s):  
Shear Deformation ◽  
Beam Theory ◽  
Material Design ◽  
Mode Shapes ◽  
Cross Sectional ◽  
Advanced Composite Materials ◽  
Design Variables ◽  
Maximum Stiffness ◽  
Thin Walled ◽  
Materials Used

The natural frequencies and mode shapes of thin-walled beams constructed of walls, or panels, of advanced composite materials depend upon both the geometry of the cross-section and the mechanical properties of the materials used in the panels. A shear deformation beam theory having the form of a Timoshenko beam theory is used to investigate the influence of these design variables. It is found that the maximum stiffness of a particular beam configuration is obtained when the contributions from the bending and shearing modes of deformation are optimized. Results show the influence of shear deformation even in the fundamental mode of vibration. Simply-supported, cantilever and free-free beams of various cross-sectional shapes and materials are analyzed.

In-Plane Bending and Shear Deformation of Belt Contributions on Tire Cornering Stiffness Characteristics

2020 ◽  
Author(s):  
Gibin Gil ◽  
Sujin Lee
Keyword(s):  
Mathematical Model ◽  
Shear Deformation ◽  
Beam Theory ◽  
Slip Angle ◽  
Wear Properties ◽  
Angle Change ◽  
Foundation Model ◽  
Plane Bending ◽  
Stiffness Characteristics ◽  
Brush Model

ABSTRACT In radial tires, belt structure plays a role of minimizing the lateral deflection of carcass, which has a significant influence on the cornering and wear properties of a tire. The deflection of carcass affects the magnitude of tread block deformation when the tire is under the slip angle. As a result, it can change the cornering stiffness characteristics of the tire, especially when the vertical load is high. During tire development, a tire design engineer tries to find the optimal belt ply angle that satisfies the various performance requirements simultaneously, but it is not an easy task because the effect of belt angle change is different depending on the size of the tire. There have been many attempts to construct a mathematical model that represents the structural properties of the belt package, including the string-based model and the beam on elastic foundation model. But, in many cases, only the in-plane bending of belt is considered and the shear deformation is not taken into consideration. In this study, the effect of belt angle change on belt stiffness is analyzed using a mathematical model based on the Timoshenko beam theory. This model can account for the in-plane bending and shear deformation of the belt structure at the same time. The results of the analysis show how the contribution of bending and shear is changed depending on a tire design parameter, herein the belt cord angle. The effect of belt ply angle change on cornering stiffness is investigated by means of the brush model including belt flexibility. The prediction by the brush model is compared with the measurement using a Flat-trac machine, and the validity of the model is discussed.

scholarly journals Estimating Deterioration in the Concrete Tie-Ballast Interface Based on Vertical Tie Deflection Profile: A Numerical Study

2016 ◽  
Author(s):  
Hailing Yu
Keyword(s):  
Direct Detection ◽  
Numerical Study ◽  
Interface Condition ◽  
Vertical Deflection ◽  
Cohesive Elements ◽  
Material Loss ◽  
Element Analysis ◽  
Cross Sectional ◽  
Technical Requirements ◽  
Support Conditions

In ballasted concrete tie track, the tie-ballast interface can deteriorate resulting in concrete tie bottom abrasion, ballast pulverization and/or voids in tie-ballast interfaces. Tie-ballast voids toward tie ends can lead to unfavorable center binding support conditions that can result in premature concrete tie failure and possible train derailment. Direct detection of these conditions is difficult. There is a strong interest in assessing the concrete tie-ballast interface conditions indirectly using measured vertical deflections. This paper seeks to establish a link between the vertical deflection profile of a concrete tie top surface and the tie-ballast interface condition using the finite element analysis (FEA) method. The concrete tie is modeled as a concrete matrix embedded with prestressing steel strands or wires. The configurations of two commonly used concrete ties, one with 8 prestressing strands and the other with 20 prestressing wires, are employed in this study. All models are three-dimensional and symmetric about the tie center. A damaged plasticity model that can predict onset and propagation of tensile cracks is applied to the concrete material. The steel-concrete interface is homogenized and represented with a thin layer of cohesive elements sandwiched between steel and concrete elements. Strand- or wire-specific elasto-plastic bond models developed at the Volpe Center are applied to the cohesive elements to account for the interface bonding mechanisms. FE models are developed for both original and worn concrete ties, with the latter assuming hypothetical patterns of reduced cross sections resulting from abrasive interactions with the ballast. Static analyses of pretension release in these concrete ties are conducted, and vertical deflection gradients along tie lengths are calculated and shown to correspond well with the worn cross sectional patterns for a given reinforcement type. The ballast is further modeled with Extended Drucker-Prager plasticity, and hypothetical voids are applied toward the tie ends along the concrete tie-ballast interface to simulate center binding support conditions. The distance range over which the concrete tie is supported in the center is variable and yields different center binding severity. Static simulations are completed with vertical rail seat loads applied on the concrete tie-ballast assembly. The influences of various factors on the vertical deflection profile, including tie type, vertical load magnitude, center binding severity, cross sectional material loss and prestress loss, are examined based on the FEA results. The work presented in this paper demonstrates the potential of using the vertical deflection profile of concrete tie top surfaces to assess deteriorations in the tie-ballast interface. The simulation results further help to clarify minimum technical requirements on inspection technologies that measure concrete tie vertical deflection profiles.

On the shear deformation modes in the framework of Generalized Beam Theory

2014 ◽  
Vol 84 ◽  
pp. 325-334 ◽  
Author(s):  
Rodrigo Gonçalves ◽  
Rui Bebiano ◽  
Dinar Camotim
Keyword(s):  
Shear Deformation ◽  
Beam Theory ◽  
Deformation Modes ◽  
Generalized Beam Theory
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