The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
David Thambiratnam - One of the best experts on this subject based on the ideXlab platform.
-
Dynamic Characteristics of steel-deck composite floors under human-induced loads
Computers & Structures, 2009Co-Authors: Sandun S. De Silva, David ThambiratnamAbstract:This paper treats the Dynamic Characteristics of a multi-panel floor system under human-induced loads, using finite element techniques. Load models with variable parameters of intensity, foot contact ratio, frequency and damping are developed and applied as pattern loads. Panel response in terms of deflections and accelerations are evaluated and used to assess the panel for suitable occupancies. Results indicate the occurrence of multimodal vibration in these structures and the importance of applying pattern loads to capture these modes. Vibration caused by the higher harmonics of the activity frequency can also cause discomfort and excessive deflections in the floor panels.
-
Dynamic Characteristics of steel deck composite floors under human induced loads
Faculty of Built Environment and Engineering, 2009Co-Authors: Sandun S. De Silva, David ThambiratnamAbstract:Steel-deck composite floor systems are a popular choice in high-rise buildings as they are economical and easy to construct. These composite floor systems use high strength materials to achieve longer spans, but are slender and vulnerable to vibration under human induced loads. These floors are normally designed using static methods which will not capture the true Dynamic response resulting in inappropriate designs, undesirable vibration and discomfort to occupants. At present there is no adequate design guidance to address the vibration in these composite floors, due to a lack of research information on their Dynamic Characteristics, resulting in wasteful post event retrofits
Sandun S. De Silva - One of the best experts on this subject based on the ideXlab platform.
-
Dynamic Characteristics of steel-deck composite floors under human-induced loads
Computers & Structures, 2009Co-Authors: Sandun S. De Silva, David ThambiratnamAbstract:This paper treats the Dynamic Characteristics of a multi-panel floor system under human-induced loads, using finite element techniques. Load models with variable parameters of intensity, foot contact ratio, frequency and damping are developed and applied as pattern loads. Panel response in terms of deflections and accelerations are evaluated and used to assess the panel for suitable occupancies. Results indicate the occurrence of multimodal vibration in these structures and the importance of applying pattern loads to capture these modes. Vibration caused by the higher harmonics of the activity frequency can also cause discomfort and excessive deflections in the floor panels.
-
Dynamic Characteristics of steel deck composite floors under human induced loads
Faculty of Built Environment and Engineering, 2009Co-Authors: Sandun S. De Silva, David ThambiratnamAbstract:Steel-deck composite floor systems are a popular choice in high-rise buildings as they are economical and easy to construct. These composite floor systems use high strength materials to achieve longer spans, but are slender and vulnerable to vibration under human induced loads. These floors are normally designed using static methods which will not capture the true Dynamic response resulting in inappropriate designs, undesirable vibration and discomfort to occupants. At present there is no adequate design guidance to address the vibration in these composite floors, due to a lack of research information on their Dynamic Characteristics, resulting in wasteful post event retrofits
Juipi Hung - One of the best experts on this subject based on the ideXlab platform.
-
effect of preload of linear guides on Dynamic Characteristics of a vertical column spindle system
International Journal of Machine Tools & Manufacture, 2010Co-Authors: Juipi HungAbstract:Realization on the Dynamic Characteristics of the column–spindle system is of importance for enhancing the structural performance of a vertical milling machine. Generally, the spindle head is fed under linear guide mechanism through a ball-screw driver. To assess the Dynamic Characteristics of a vertical column–spindle system under the influence of a linear guide, this study developed a finite element model integrated with the modeling of linear components with the implementation of contact stiffness at the rolling interface. Both the finite element simulations and the vibration tests reveal that the preload of a linear guide greatly affects the vibration behavior associated with a spindle head, and the Dynamic stiffness of the spindle head could be enhanced by increasing the preload of the linear guide. Current results clearly indicate that the simulations agree well with the experimental measurements. This also confirms that the proposed model can be successfully applied to evaluate the Dynamics Characteristics of machine tool systems of various configurations.
Jeremy Carter - One of the best experts on this subject based on the ideXlab platform.
-
Dynamic Characteristics of the diverging taper honeycomb stator seal
Journal of Turbomachinery-transactions of The Asme, 2006Co-Authors: Anthony J Smalley, Massimo Camatti, Dara W Childs, Justin R Hollingsworth, Giuseppe Vannini, Jeremy CarterAbstract:This paper introduces a variant on the honeycomb-stator seal, which can extend the already strong stabilizing influence of this seal geometry for centrifugal compressors. The paper presents predicted and measured Dynamic Characteristics, demonstrating how a clearance, which diverges axially from inlet to outlet, increases the maximum effective damping of a honeycomb-stator seal, even though the average clearance is increased. The results also show a strong negative direct stiffness at zero and low frequency for this seal geometry (termed the "diverging taper honeycomb seal (DTHCS)"). The predictions are made with ISOTSEAL, software developed at The Texas A&M Turbomachinery Laboratory. (This code was developed within the Turbomachinery Laboratory and is not a commercial product (not for sale).) The test data, also obtained at the Turbomachinery Laboratory, confirm the nature and magnitude of both these Dynamic Characteristics with close fidelity. However, measured leakage falls significantly below predicted leakage. The frequency dependence of the seal Dynamic Characteristics and the strong negative static stiffness require careful attention in rotor Dynamics analysis.
-
Dynamic Characteristics of the diverging taper honeycomb stator seal
ASME Turbo Expo 2004: Power for Land Sea and Air, 2004Co-Authors: Anthony J Smalley, Massimo Camatti, Dara W Childs, Justin R Hollingsworth, Giuseppe Vannini, Jeremy CarterAbstract:This paper introduces a variant on the honeycomb-stator seal, which can extend the already strong stabilizing influence of this seal geometry for centrifugal compressors. The paper presents predicted and measured Dynamic Characteristics, demonstrating how a clearance, which diverges axially from inlet to outlet, increases the maximum effective damping of a honeycomb-stator seal, even though the average clearance is increased. The results also show a strong negative direct stiffness at zero and low frequency for this seal geometry (termed the “Diverging Taper Honeycomb Seal (DTHCS)”). The predictions are made with ISOTSEAL, software developed at The Texas A&M Turbomachinery Laboratory. The test data, also obtained at the Turbomachinery Laboratory, confirms the nature and magnitude of both these Dynamic Characteristics with close fidelity. However, measured leakage falls significantly below predicted leakage. The frequency dependence of the seal Dynamic Characteristics and the strong negative static stiffness require careful attention in rotor Dynamics analysis.Copyright © 2004 by ASME
S K Laha - One of the best experts on this subject based on the ideXlab platform.
-
steady state and Dynamic Characteristics of axial grooved journal bearings
Tribology International, 2009Co-Authors: L. Roy, S K LahaAbstract:Abstract The steady state and Dynamic Characteristics including whirl instability of oil journal bearings with single axial groove located at the top of the bearing and then at some angular interval from the top from which oil is supplied at constant pressure are obtained theoretically. The Reynolds equation is solved numerically by finite difference method satisfying the appropriate boundary conditions. The Dynamic behaviour in terms of stiffness and damping coefficients of fluid film and stability are found using a first-order perturbation method for each location of the groove. It has been shown that both load capacity, end flow is maximum when the feeding groove is at 12° location and thereafter the load capacity falls, stability improves for smaller groove angle and groove length at higher value of eccentricity ratio and speed. The stiffness and damping coefficient magnitude is found to be higher for the bearing with smaller groove angle and groove length, the difference between the hydroDynamic and hydrostatic load increases at 12° groove location.
