Dynamic Properties of Long-Span Steel-Concrete Composite Bridges with External Tendons

2013 ◽  
Vol 831 ◽  
pp. 359-363
Author(s):  
Wei An Wang ◽  
Qiao Li ◽  
Can Hui Zhao ◽  
Wei Lin Zhuang
Keyword(s):  
Dynamic Properties ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Dynamic Interactions ◽  
Element Analysis ◽  
Structural Dynamic ◽  
Equivalent Damping ◽  
Shear Connectors ◽  
External Tendons ◽  
Composite Bridges

The dynamic performance of large-span steel-concrete composite bridges with external tendons is investigated by deriving the formula of equivalent damping ratios of composite bridges, and by considering the influence of shear connectors stiffness of composite girders, external tendons, and pile-soil dynamic interactions on the dynamic properties of steel-concrete composite bridge. Finite element analysis indicates that the equivalent damping ratio has a significant influence on the dynamic response and damping coefficient adjusted must be conducted in structural dynamic analysis.

Experiences From Structural Dynamic Analysis Projects of BWR Plants Within the Scope of Power Uprate Projects Using FEA

2010 ◽  
Author(s):  
Bjo¨rn Sva¨rd ◽  
Jan-Anders Larsson ◽  
Philip Ma˚rtensson ◽  
Bjo¨rn Lundin
Keyword(s):  
Finite Element Analysis ◽  
Dynamic Analysis ◽  
Structural Models ◽  
Dynamic Interactions ◽  
Element Analysis ◽  
Structural Dynamic ◽  
Global Models ◽  
Dynamic Verification ◽  
Strong Dynamic ◽  
Reactor Pressure

During recent years, power-uprate projects have been executed at several BWR-units in Sweden. As part of these projects, structural verification of the safety-related buildings as well as the new and old internal parts of the reactor pressure vessel, RPV, has been performed. In this document, some experiences will be presented from structural dynamic verification, using finite element analysis, FEA, within the scope of these power uprate projects. From this work, a number of conclusions can be drawn. Global models with dense meshes can successfully be used for a broad range of applications. Today, large FEA-models can be used efficiently, e.g. in global vibration and structural verification analyses, if suitable dynamic analysis methods are used. There can be strong dynamic interactions between the containment, fluids, the RPV and RPV-internals. Stress calculation and evaluation can be executed efficiently on large models. The structural models can with advantage be re-utilized in future projects.

Structural Dynamic Topology Optimization of the Transmission Housing

2011 ◽  
Vol 308-310 ◽  
pp. 368-372
Author(s):  
Shou Wen Yao ◽  
Jian Li Lv ◽  
Qing Dong Peng
Keyword(s):  
Topology Optimization ◽  
Dynamic Performance ◽  
Cad Model ◽  
Mass Reduction ◽  
Element Analysis ◽  
Structural Dynamic ◽  
Design Variables ◽  
The Finite Element Analysis ◽  
Dynamic Topology ◽  
Topology Model

Dynamic performance is one of the most important factors in the product’s life. Transmission housing is one of the important components in vehicle, which has direct influence on the vehicle’s powertrain performance. Dynamic topology optimization can improve the product’s performance. The dynamic topology model is built, in which the density of elements are the design variables, the displacement of frequency response and volume are the constraints, and the objective is to maximize the first natural frequency of the housing. According to the result of optimization, the CAD model of housing is rebuilt and the finite element analysis of the new housing is done.The results show that both the static and dynamic performance are improved besides the mass reduction, namely, dynamic topology optimization can significantly improve the product’s performance.

Experimental Validation of Non-Conventional Viscoelastic Models via Equivalent Damping Estimates

2008 ◽  
Author(s):  
Giuseppe Catania ◽  
Silvio Sorrentino
Keyword(s):  
Damping Ratio ◽  
Viscoelastic Model ◽  
Measurement Data ◽  
Vibration Measurement ◽  
Modal Parameter ◽  
Structural Dynamic ◽  
General Validity ◽  
Integer Order ◽  
Equivalent Damping ◽  
Viscoelastic Models

Non-conventional rheological models based on non-integer order differential operators can be used to describe the viscoelastic behavior of materials, especially of polymers. These models are usually selected and then validated by means of creep and relaxation tests. However, engineers dealing with structural dynamic problems may need to obtain model identification from vibration measurement data. In this case, however, the direct identification of an optimal set of parameters of a viscoelastic model from time or frequency domain measurements is a difficult task, especially if the structural dissipative contributions are slight. In this paper, an indirect approach is adopted, based on the concept of damping ratio. When dealing with standard linear viscous dissipative models, a damping ratio modal parameter ζn can be analytically defined and experimentally estimated. But this theoretical parameter shows a dependency from the modal frequency that may dramatically fail in fitting the experimental data. On the contrary, it is known that a better agreement between theory and experiments can be achieved by means of non-integer order differential models, even though in this case analytical expressions for ζn are difficult to find. To overcome this difficulty, a method of general validity for viscoelastic models is developed, based on the concept of equivalent damping ratio and on the circle-fit technique. The proposed method is applied to experimental damping estimates from plane flexural vibrations of clamped-free beams, obtained from specimens of different size made of materials such as Polyethylene, Polyvinyl-chloride and Delrin.

Study on Bearing Dynamic Properties of Nano-Particle Reinforced ZA27 Alloy Composite Material

2011 ◽  
Vol 328-330 ◽  
pp. 1467-1470
Author(s):  
Zhou Qin ◽  
Kun Peng Ma
Keyword(s):  
Aluminum Alloy ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Nano Particles ◽  
Zinc Alloy ◽  
Element Analysis ◽  
Application Range ◽  
Za27 Alloy ◽  
Frictional Characteristic ◽  
The Finite Element Analysis

Although the zinc-aluminum alloy has gotten substantial increase in terms of strength and friction characteristics than the traditional zinc alloy, it has limitation in the operating temperature and speed. In order to further improve the frictional characteristic and expand its application range, we adopted the inexpensive zinc-aluminum alloy of ZA27 reinforced by TiC nano-particles to replace the traditional bronze alloys (ZQSn6-6-3) to produce bearing bush. And through its dynamic performance of the finite element analysis to prove particle reinforced ZA27 bearing bush has good dynamic performance.

Modal Analysis of Linear Guide Way Junction Surface

2013 ◽  
Vol 380-384 ◽  
pp. 105-108
Author(s):  
Sheng Le Ren ◽  
Tian Yu Cheng ◽  
Ye Dai
Keyword(s):  
Damping Ratio ◽  
Dynamic Performance ◽  
Surface Characteristics ◽  
Test Method ◽  
Joint Surface ◽  
Small Scale ◽  
Static Stiffness ◽  
Element Analysis ◽  
Scale Test ◽  
The Many

Rails is an affordable, fixed, direct the mobile device. Among the many factors that affect performance, the rail surface is a very important factor. This article use test method gets the static stiffness of joint surface and the top five bands of the natural frequency and damping ratio for small linear guides. Test access to the static stiffness will be important in finite element analysis of input parameters. In the course of the study, analysis of dynamic performance of small - scale test guide, Study on Effect of surface characteristics on the structure of the component. By comparing the small guide the results of the analysis and the experimental results to verify the validity and accuracy of the analysis method.

scholarly journals Structural Dynamic Improvement for Petal-Type Deployable Solid-Surface Reflector Based on Numerical Parameter Study

2020 ◽  
Vol 10 (18) ◽  
pp. 6560
Author(s):  
He Huang ◽  
Qiang Cheng ◽  
Lei Zheng
Keyword(s):  
Solid Surface ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Dynamic Test ◽  
Mode Shapes ◽  
Design Parameters ◽  
Prototype Model ◽  
Parameter Study ◽  
Structural Dynamic ◽  
Replacement Method

Petal-type Deployable Solid-surface Reflector (PDSR) is a kind of important structure widely applied in deployable reflector antennas in aerospace engineering. The dynamic properties of this reflector structure in deployed state are significant to the reflector accuracy for antennas. However, the study of the dynamic evaluation of deployable structure with revolute joints is difficult and seldom concerned by researchers. In order to study dynamic properties of the PDSR, the Cable Replacement Method (CRM) was utilized to equivalently simulate the nonlinear structural stiffness of the revolute joint for numerical analyses. The Finite Element Model (FEM) of this reflector structure was established by commercial software ANSYS (ANSYS Inc., Canonsburg, PA, USA) and verified by the theoretical analysis and dynamic test of actual prototype model. The natural frequencies and mode shapes of deployed reflector were computed to study the influence of drag spring design parameters as stiffness, pre-tensioned force, and distance of two adjacent linkage butts. Finally, the analysis results were concluded that the drag springs between two adjacent petals can essentially improve the dynamic performance of reflector structure in deployed state. It can be a useful technical system for future engineering applications of PDSR antennas.

scholarly journals Dynamic Response of Self-Supported Power Transmission Tower Subjected to Wind Action

2018 ◽  
Vol 7 (4.35) ◽  
pp. 476
Author(s):  
Nur Hamizah Hamzah ◽  
Fathoni Usman ◽  
Mohd Yazee Mat Yatim
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Power Transmission ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Time History ◽  
Transmission Tower ◽  
Electrical Transmission ◽  
Structural Dynamic ◽  
Wind Action

A power transmission tower carries electrical transmission conductor at adequate distance from the ground. It must withstand all nature’s forces besides its self-weight. In structural analysis, natural frequency, mode shape and damping ratio are used to define the structural dynamic properties which relate to the basic structural features. This paper described the dynamic analysis including the modal and the time history analysis on each segment of the self-supported transmission tower to understand its dynamic responses subjected to wind action. The factors such as different height above ground, a different value of wind speed and different wind angle of attack were included in this study to see the influence of those factors towards dynamic response of the structure. The contribution of the wind towards the displacement of the structure is determined in this study by comparing the result obtained in a linear static analysis which considered the load combination without and with the presence of wind action. It was found that displacement using dynamic analysis is bigger than static linear analysis. The result illustrates that the studied factors gave a significant effect on the dynamic response of the structure and the findings indicate that dynamic analysis is vital in structural design.

scholarly journals Detection of Friction Stir Welding Defects of AA1060 Aluminum Alloy Using Specific Damping Capacity

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2437 ◽  
Author(s):  
Waheed AbuShanab ◽  
Essam Moustafa
Keyword(s):  
Finite Element ◽  
Friction Stir Welding ◽  
Natural Frequency ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Impact Testing ◽  
Damping Capacity ◽  
Element Analysis ◽  
Friction Stir ◽  
Specific Damping Capacity

The demand for nondestructive testing has increased, especially in welding testing. In the current study, AA1060 aluminum plates were jointed using the friction stir welding (FSW) process. The fabricated joints were subjected to free vibration impact testing in order to investigate the dynamic properties of the welded joint. Damping capacity and dynamic modulus were used in the new prediction method to detect FSW defects. The data acquired were processed and analyzed using a dynamic pulse analyzer lab shop and ME’Scope’s post-processing software, respectively. A finite element analysis using ANSYS software was conducted on different types of designed defects to predict the natural frequency. The results revealed that defective welded joints significantly affect the specific damping capacity. As the damping ratio increased, so did the indication of opportunities to increase the presence of defects. The finite element simulation model was consistent with experimental work. It was therefore revealed that natural frequency was insufficient to predict smaller defects.

Dynamic Characterization of Car Door and Hood Panels Using FEA and EMA

2013 ◽  
Vol 471 ◽  
pp. 89-96 ◽  
Author(s):  
Zahir Hanouf ◽  
Waleed F. Faris ◽  
Mohd Jailani Mohd Nor
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Properties ◽  
Experimental Modal Analysis ◽  
Modal Testing ◽  
Dynamic Characterization ◽  
Element Analysis ◽  
Structural Dynamic

The dynamic characterization of vehicle structures is a crucial step in NVH analysis and helps in refining the vibration and noise in new vehicles. This paper investigates the dynamic properties of two parts of the vehicle structure which are door and hood panels. Theoretical modal analysis which is referred to as Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA) or modal testing has been used as investigative tools. The paper investigates the structural dynamic properties of door and hood panels of a local car. ME'scope software was used to analyze the data obtained from Pulse to extract the dynamic properties of the panels. LS-DYNA software was used to analyze the dynamic behavior of the structure. The comparison between the results obtained from both analyses showed some similarity in frequencies and mode shapes. Finally the paper concludes that experimental modal analysis and finite element analysis can both be used to extract dynamic properties of structures.

Structural Dynamics Analysis of Three-Dimensional Bi-Axial Sun-Tracking System Structure Determined by Numerical Modal Analysis

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Fateh Ferroudji ◽  
Cherif Khelifi ◽  
Toufik Outtas
Keyword(s):  
Large Scale ◽  
Tracking System ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
System Structure ◽  
Quality Factors ◽  
Element Analysis ◽  
Structural Dynamic ◽  
Modal Damping ◽  
Key Factor

Sun-tracking system (STS) is a key factor for solar photovoltaic (PV) future and new answers for the solar market. It will expand large-scale PV projects (PV farms) worldwide, and it is possible to collect more energy from the sun. PV farms consist of thousands of STS that are subject to dynamic loads (wind, snow, etc.), vibrations, and gravitational loads. This paper presents the structural dynamic analysis of a 24 m2 bi-axial STS (azimuth-elevation) at different elevation angles based on its modal parameters (natural frequencies, modal shapes, and modal damping ratios) and dynamic performance indices (modal participation factors (MPF), forcing frequencies, and mechanical quality factors) by means of the finite element analysis (FEA). The simulation results show that the structural dynamic design of the STS meets the desired structural requirements and agrees well with structural dynamic standards (EN 1991-1-4 and ASHRAE). These results can be used for further analysis on optimal design and vibration safety verification for the bi-axial STS (PV applications).

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