The Experts below are selected from a list of 102228 Experts worldwide ranked by ideXlab platform
Tarun Kant - One of the best experts on this subject based on the ideXlab platform.
-
effect of cross sectional warping of anisotropic sandwich laminates due to Dynamic Loads using a refined theory and c finite elements
International Journal for Numerical Methods in Engineering, 1992Co-Authors: Tarun KantAbstract:An attempt has been made to study the effect of cross-sectional warping in the symmetrically laminated anisotropic composite sandwich plates for transient Loads. A higher-order shear deformation theory (HOST) is used in conjunction with the simple displacement based C° finite element method (FEM). As is well-known, the classical first-order theories hitherto considered were inadequate to describe the propagation of waves in the highly orthotropic sandwich laminates. The present theory, which is more accurate than the Reissner-Mindlin theory, is applied herein, for the evaluation of plate response to different types of Dynamic Loads. An explicit central difference scheme is employed for the integration of Dynamic equations of equilibrium with a diagonalized mass matrix obtained by a special procedure applicable to quadrilateral isoparametric elements. The numerical results of the present investigation have been compared with the first-order shear deformation theory (FOST) and the differences between HOST and FOST are examined. The results presented here should be useful in obtaining better correlation between theory and experiment, and to numerical analysts in verifying their results.
-
Effect of cross‐sectional warping of anisotropic sandwich laminates due to Dynamic Loads using a refined theory and C° finite elements
International Journal for Numerical Methods in Engineering, 1992Co-Authors: Mallikarjuna, Tarun KantAbstract:An attempt has been made to study the effect of cross-sectional warping in the symmetrically laminated anisotropic composite sandwich plates for transient Loads. A higher-order shear deformation theory (HOST) is used in conjunction with the simple displacement based C° finite element method (FEM). As is well-known, the classical first-order theories hitherto considered were inadequate to describe the propagation of waves in the highly orthotropic sandwich laminates. The present theory, which is more accurate than the Reissner-Mindlin theory, is applied herein, for the evaluation of plate response to different types of Dynamic Loads. An explicit central difference scheme is employed for the integration of Dynamic equations of equilibrium with a diagonalized mass matrix obtained by a special procedure applicable to quadrilateral isoparametric elements. The numerical results of the present investigation have been compared with the first-order shear deformation theory (FOST) and the differences between HOST and FOST are examined. The results presented here should be useful in obtaining better correlation between theory and experiment, and to numerical analysts in verifying their results.
Shengyang Zhu - One of the best experts on this subject based on the ideXlab platform.
-
interface damage and its effect on vibrations of slab track under temperature and vehicle Dynamic Loads
International Journal of Non-linear Mechanics, 2014Co-Authors: Shengyang Zhu, Chengbiao CaiAbstract:Abstract This paper presents a three-dimensional finite element model to investigate the interface damage occurred between prefabricated slab and CA (cement asphalt) mortar layer in the China Railway Track System (CRTS-II) slab track system. In the finite element model, a cohesive zone model with a non-linear constitutive law is introduced and utilized to model the damage, cracking and delamination at the interface. Combining with the temperature field database obtained from the three-dimensional transient heat transfer analysis, the interface damage evolution as a result of temperature change is analyzed. A three-dimensional coupled Dynamic model of a vehicle and the slab track is then established to calculate the varying rail-supporting forces which are utilized as the inputs to the finite element model. The non-linearities of the wheel–rail contact geometry, the wheel–rail normal contact force and the wheel–rail tangential creep force are taken into account in the model. Setting the maximum interface damaged state calculated under temperature change as the initial condition, the interface damage evolution and its influence on the Dynamic response of the slab track are investigated under the joint action of the temperature change and vehicle Dynamic load. The analysis indicates that the proposed model is capable of predicting the initiation and propagation of cracks at the interface. The prefabricated slab presents lateral warping, resulting in severe interface damage on both the sides of the slab track along the longitudinal direction during temperature drop process, while the interface damage level does not change significantly under vehicle Dynamic Loads. The interface damage has great effects on the Dynamic responses of the slab track.
Chengbiao Cai - One of the best experts on this subject based on the ideXlab platform.
-
interface damage and its effect on vibrations of slab track under temperature and vehicle Dynamic Loads
International Journal of Non-linear Mechanics, 2014Co-Authors: Shengyang Zhu, Chengbiao CaiAbstract:Abstract This paper presents a three-dimensional finite element model to investigate the interface damage occurred between prefabricated slab and CA (cement asphalt) mortar layer in the China Railway Track System (CRTS-II) slab track system. In the finite element model, a cohesive zone model with a non-linear constitutive law is introduced and utilized to model the damage, cracking and delamination at the interface. Combining with the temperature field database obtained from the three-dimensional transient heat transfer analysis, the interface damage evolution as a result of temperature change is analyzed. A three-dimensional coupled Dynamic model of a vehicle and the slab track is then established to calculate the varying rail-supporting forces which are utilized as the inputs to the finite element model. The non-linearities of the wheel–rail contact geometry, the wheel–rail normal contact force and the wheel–rail tangential creep force are taken into account in the model. Setting the maximum interface damaged state calculated under temperature change as the initial condition, the interface damage evolution and its influence on the Dynamic response of the slab track are investigated under the joint action of the temperature change and vehicle Dynamic load. The analysis indicates that the proposed model is capable of predicting the initiation and propagation of cracks at the interface. The prefabricated slab presents lateral warping, resulting in severe interface damage on both the sides of the slab track along the longitudinal direction during temperature drop process, while the interface damage level does not change significantly under vehicle Dynamic Loads. The interface damage has great effects on the Dynamic responses of the slab track.
Łukasz Jankowski - One of the best experts on this subject based on the ideXlab platform.
-
Off-line identification of Dynamic Loads
Structural and Multidisciplinary Optimization, 2009Co-Authors: Łukasz JankowskiAbstract:This paper considers off-line identification of spatial and temporal characteristics of a Dynamic load, and is focused on the case of a limited number of sensors. Both elastic and elasto-plastic structural behaviours are taken into account. The identification is performed off-line, based on optimisation of modelled local structural responses, and—in the case of limited number of sensors—identifies an observationally equivalent load, which in a given sense optimally approximates the actual load. Compared to previous researches this approach allows to identify general Dynamic Loads of unknown locations, including multiple impacts and moving Loads, and gives more insight into the identification process by distinguishing between the reconstructible and unreconstructible load components. Additionally, the problem of optimum sensor location is discussed.
Ling Yu - One of the best experts on this subject based on the ideXlab platform.
-
Evaluation of Dynamic Loads on a skew box girder continuous bridge - Part II: Parametric study and Dynamic load factor
2007Co-Authors: Demeke B. Ashebo, Tommy H.t. Chan, Ling YuAbstract:Studies on Dynamic Loads are important for bridge engineering as well as pavement design. A large number of research studies have indicated that bridge Dynamic Loads increase road surface damage by a factor of 2-4. Although the field test is the best available approach to understanding actual vehicle-induced Dynamic Loads on bridges, according to pervious studies there is only a limited amount of field data available on skew box girder continuous bridges. This paper presents an evaluation of vehicle-induced Dynamic Loads, based on a field test that was carried out on a skew box girder continuous bridge as reported in a companion paper (Part I). The effects of different parameters such as the weight, speed, type, number of axles and position of vehicles on Dynamic Loads are investigated. Based on the statistical analysis, the use of the Dynamic load factor (DLF) is proposed. The Dynamic load factor obtained in this study is less than the values provided by most bridge design codes.
-
evaluation of Dynamic Loads on a skew box girder continuous bridge part i field test and modal analysis
Engineering Structures, 2007Co-Authors: Demeke B. Ashebo, Tommy H.t. Chan, Ling YuAbstract:Abstract Field measurements were carried out to evaluate Dynamic Loads on an existing skew box girder continuous bridge. This paper presents the experimental procedure, the data acquisition system, the calibration test, the modal analysis and the load distribution in a transversal direction. A three-axle heavy truck was hired for use in the test to calibrate the field measurements. The static and Dynamic bending moments of the tested bridge induced by the calibration truck were obtained. The relationship between the measured strain and bending moment were determined. Information on the Dynamic behaviours of the bridge were obtained from an experimental and theoretical modal analysis. The influence of skewness on the static and Dynamic behaviours of the bridge as well as on the load distribution in the transversal direction for the calibration truck and in-service vehicles was investigated. It was found that the influence of skew in both the static and Dynamic behaviours of the bridge within the skew angle range of 0 ∘ –30 ∘ is very small.
-
evaluation of Dynamic Loads on a skew box girder continuous bridge part i field test and modal analysis
Faculty of Built Environment and Engineering, 2007Co-Authors: Demeke B. Ashebo, Tommy H.t. Chan, Ling YuAbstract:Field measurements were carried out to evaluate Dynamic Loads on an existing skew box girder continuous bridge. This paper presents the experimental procedure, the data acquisition system, the calibration test, the modal analysis and the load distribution in a transversal direction. A three-axle heavy truck was hired for use in the test to calibrate the field measurements. The static and Dynamic bending moments of the tested bridge induced by the calibration truck were obtained. The relationship between the measured strain and bending moment were determined. Information on the Dynamic behaviours of the bridge were obtained from an experimental and theoretical modal analysis. The influence of skewness on the static and Dynamic behaviours of the bridge as well as on the load distribution in the transversal direction for the calibration truck and in-service vehicles was investigated. It was found that the influence of skew in both the static and Dynamic behaviours of the bridge within the skew angle range of 0 degrees-30 degrees is very small.
