Transmission of vibration and energy through layered and jointed plates subjected to shock excitation

2011 ◽  
Vol 226 (7) ◽  
pp. 1765-1777 ◽  
Author(s):  
Huifang Xiao ◽  
Yimin Shao ◽  
Chris K Mechefske
Keyword(s):  
Dynamic Responses ◽  
Transmission Ratio ◽  
Nonlinear Behaviour ◽  
Energy Transmission ◽  
Layered Plates ◽  
Element Analysis ◽  
Vibration Transmission ◽  
Shock Excitation ◽  
Shock Amplitude ◽  
Multiple Interfaces

In this article, the vibration and energy transmission characteristics at the multiple interfaces of layered and jointed plates associated with friction are studied as a function of the shock loading amplitude using the established ‘sphere-joint assembled multi-layered plates’ model. The dynamic responses at the multiple interfaces under shock excitation are calculated using finite element analysis. The transmissions of vibration and energy through the multiple interfaces are characterized by the defined vibration and energy transmission ratios. Results show that the acceleration amplitudes at different interfaces increase nonlinearly with the shock amplitude and they are approximated by a third-order polynomial function. The acceleration amplitude nonlinearly decreases along the transmitting interfaces and the maximum attenuation occurs between the first and second transmitting interfaces. A minimum vibration transmission ratio is observed for the range of shock amplitude considered and the value of shock amplitude leading to the minimum is identical for different transmitting interfaces. It is also shown that the energy transmission ratio exhibits a nonlinear behaviour similar to that of the vibration transmission ratio. The expression for determining the shock amplitude resulting in peak energy transmission ratio at the input interface is also presented. Experimental validation is performed, which shows good agreement with numerical results.

Performance enhancement of normal contact ratio gearing system through correction factor

2019 ◽  
Vol 13 (3) ◽  
pp. 5242-5258
Author(s):  
R. Ravivarman ◽  
K. Palaniradja ◽  
R. Prabhu Sekar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Correction Factor ◽  
Bending Strength ◽  
Performance Enhancement ◽  
Transmission Ratio ◽  
Contact Ratio ◽  
Element Analysis ◽  
Normal Contact ◽  
Root Region

As lined, higher transmission ratio drives system will have uneven stresses in the root region of the pinion and wheel. To enrich this agility of uneven stresses in normal-contact ratio (NCR) gearing system, an enhanced system is desirable to be industrialized. To attain this objective, it is proposed to put on the idea of modifying the correction factor in such a manner that the bending strength of the gearing system is improved. In this work, the correction factor is modified in such a way that the stress in the root region is equalized between the pinion and wheel. This equalization of stresses is carried out by providing a correction factor in three circumstances: in pinion; wheel and both the pinion and the wheel. Henceforth performances of this S+, S0 and S- drives are evaluated in finite element analysis (FEA) and compared for balanced root stresses in parallel shaft spur gearing systems. It is seen that the outcomes gained from the modified drive have enhanced performance than the standard drive.

Dynamic Analysis of Large-Scale Power House

2012 ◽  
Vol 446-449 ◽  
pp. 837-840
Author(s):  
Yu Zhao ◽  
Shu Fang Yuan ◽  
Jian Wei Zhang
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Large Scale ◽  
Three Dimensional ◽  
Dynamic Responses ◽  
Dynamic Loads ◽  
Element Analysis ◽  
Power House ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The underwater structure of power house is major structure under the dynamic loads of unit. The vibration problem is very common in operation. So the structures should have sufficient stiffness to resist dynamic loads of unit. This paper establishes three-dimensional finite element models with finite element analysis software—ANSYS. Dynamic characteristics of the power house and dynamic responses of structure under earthquake are analyzed. The results of the computation show that fluid-solid coupling may be ignored when studying dynamic characteristics of structures of the underground power house.

scholarly journals Nonlinear behaviour of reinforced concrete flat slabs after a column loss event

2018 ◽  
Vol 21 (14) ◽  
pp. 2169-2183 ◽  
Author(s):  
Justin M Russell ◽  
John S Owen ◽  
Iman Hajirasouliha
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Progressive Collapse ◽  
Nonlinear Behaviour ◽  
Dynamic Amplification Factor ◽  
Element Analysis ◽  
Flat Slab ◽  
Standard Design ◽  
Loss Event ◽  
Dynamic Amplification

Previous studies have demonstrated that reinforced concrete flat slab structures could be vulnerable to progressive collapse. Although such events are dynamic, simplified static analyses using the sudden column loss scenario are often used to gain an indication into the robustness of the structure. In this study, finite element analysis is used to replicate column loss scenarios on a range of reinforced concrete flat slab floor models. The model was validated against the results of scaled-slab experiments and then used to investigate the influence of different geometric and material variables, within standard design ranges, on the response of the structure. The results demonstrate that slab elements are able to effectively redistribute loading after a column loss event and therefore prevent a progressive collapse. However, the shear forces to the remaining columns were 159% of their fully supported condition and increased to 300% when a dynamic amplification factor of 2.0 was applied. It is shown that this can potentially lead to a punching shear failure in some of the slab elements.

Finite element analysis of soil–steel structures

1983 ◽  
Vol 10 (2) ◽  
pp. 287-294 ◽  
Author(s):  
Hisham Hafez ◽  
George Abdel-Sayed
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computation Time ◽  
Steel Structures ◽  
Nonlinear Behaviour ◽  
Construction Simulation ◽  
Element Analysis ◽  
Interface Elements ◽  
State Highway ◽  
Strain Relationship

The present paper introduces some improvements in the finite element analysis of soil–steel structures. It applies two-noded spring-type interface elements and accounts for the compaction effects during construction simulation. The analyses are performed in increments using a hyperbolic stress–strain relationship for the nonlinear behaviour of the soil and take into account the shear or tension failure in the soil elements. Also, a combination of constant and compatible linear strain elements for soil is used to increase the accuracy of the analysis around the conduit while keeping the storage requirement and computation time for the numerical solution manageable.The analytical results show satisfactory agreement with those obtained experimentally. They also show that the American Association of State Highway and Transportation Officials (AASHTO) provisions overestimate the thrust due to live load and underestimate the thrust due to dead load. A better comparison is found with the Ontario Highway Bridge Design Code (OHBDC).

Design of a High-Bandwidth XY Nanopositioning Stage for High-Throughput Micro/Nano Manufacturing

2010 ◽  
Author(s):  
Sebastian Polit ◽  
Jingyan Dong
Keyword(s):  
Mechanism Design ◽  
High Throughput ◽  
Closed Loop ◽  
Open Loop ◽  
Dynamic Responses ◽  
Element Analysis ◽  
Loop Bandwidth ◽  
Decoupled Motion ◽  
High Bandwidth ◽  
Critical Requirement

A high natural frequency (open-loop bandwidth) is a critical requirement for nanopositioners in high-throughput nanomanufacturing and nano-metrology applications. This paper presents the design and analysis of a high-bandwidth nanopositioning XY stage. The monolithic stage design has two axes and each axis is comprised of a doubly-clamped beam and a parallelogram hybrid flexure with complaint beams and circular flexure hinges. The doubly-clamped beam that is actuated by a piezoelectric actuator acts as a linear prismatic axis. The parallelogram hybrid flexures are used to decouple the actuation effect from the other axis. The mechanism design decouples the motion in the X and Y directions and restricts parasitic rotations in the XY plane while allowing for an increased bandwidth with linear kinematics in the operating region (or workspace). Kinematic and dynamic analysis shows that the mechanical structure of the stage has decoupled motion in XY direction, while achieving high bandwidth and good linearity. Finite element analysis is adapted to verify the dynamic responses from theoretical analysis. The stage is actuated by piezoelectric stack actuators, and two capacitive gauges were added to the system to build a closed-loop positioning system. The results from frequency test show that the resonation frequencies of the two vibrational modes are over 8K Hz. The stage is capable of about 15 microns of motion along each axis with a resolution of about 1 nanometer. Due to parallel kinematic mechanism design, a uniform performance is achieved across the workspace. A PI controller is implemented for the stage and a high closed-loop bandwidth is obtained.

Research on Pulley Strain of Metal Belt CVT

2014 ◽  
Vol 952 ◽  
pp. 249-252
Author(s):  
Wu Zhang ◽  
Wei Guo ◽  
Fa Rong Kou ◽  
Yi Zhi Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Analytical Method ◽  
Compressive Strain ◽  
Continuously Variable Transmission ◽  
Transmission Ratio ◽  
Element Analysis ◽  
Variable Transmission

Pulley strain aggravated whole-Part abrasion, affected friction and lubricates state of metal belt continuously variable transmission. Pulley strain was analyzed by analytical method and finite element analysis. The results indicate that with the increase of transmission ratio, the driver pulley compressive strain is increases after reduces for a while, and the driven pulley increase. Compressive strain dense when radius is lesser and vice versa. Two methods results are basically the same, whereby demonstrating that the model is rational and that the analysis results are reliable.

Dynamic Analysis of Flexible Rotor-Ball Bearings System with Unbalance-Misalignment-Rubbing Coupling Faults

2011 ◽  
Vol 105-107 ◽  
pp. 448-453 ◽  
Author(s):  
Jun Hong Zhang ◽  
Liang Ma ◽  
Jie Wei Lin ◽  
Gui Chang Zhang
Keyword(s):  
High Frequency ◽  
Ball Bearing ◽  
Frequency Component ◽  
Sine Wave ◽  
Dynamic Responses ◽  
High Frequency Component ◽  
Element Analysis ◽  
Frequency Wave ◽  
Coupling Faults ◽  
Bearing System

Dynamic responses of flexi rotor-ball-bearing system under unbalance misalignment rubbing coupling faults are studied. Coupling faults dynamic control model of flexi-multi-system of rotor-ball-bearing system is established, based on finite element analysis and numerical integral combined simulate method. Then nonlinear bearing force and rub-impact force models are programmed in MATLAB. Analysis and compare vibration characteristics of system while under faults-free, unbalance and rub-impact faults. The result demonstrates that when system under unbalance faults, vibration frequency brought by eccentric mass is agreed with rotating speed frequency, its fundamental frequency wave add high frequency component, can show the characteristics of unbalance-rubbing faults efficiently; when system under misalignment faults, with frequency double vibration and high harmonics; when system under unbalance-misalignment-rubbing coupling faults, support force of shafting of rotor system appears high frequency responses like saw tooth based on sine wave, causing aggravation of rub-impact faults.

scholarly journals Modeling and Control of the Vibration of Two Beams Coupled with Fluid and Active Links

2012 ◽  
Vol 19 (4) ◽  
pp. 653-668 ◽  
Author(s):  
Zhiyi Zhang ◽  
Fang Hu ◽  
Zeng Li ◽  
Hongxing Hua
Keyword(s):  
Superposition Principle ◽  
Fluid Pressure ◽  
Mode Shapes ◽  
Impulse Response Functions ◽  
Response Functions ◽  
Orthogonal Functions ◽  
Element Analysis ◽  
Vibration Transmission ◽  
Modeling And Control ◽  
And Control

Investigated are modeling and control approaches for vibration analysis of two identical beams which are coupled with fluid and active mechanical links. In the modeling of the coupled beam system, orthogonal functions are used to represent vibration of the beams and the fluid-structure interaction is considered. Frequency Response Functions (FRFs) are derived from the coupled governing equations and the superposition principle for linear vibration systems. In the control of vibration of the beams, impulse response functions corresponding to the FRFs and an adaptive control algorithm are employed to attenuate vibration transmission between the two beams. Natural frequencies, mode shapes as well as the pressure distribution in the fluid are computed. The results obtained by the proposed modeling method are in good consistency with those obtained by the finite element analysis. Moreover, it is demonstrated that the active mechanical link is able to reduce vibration transmission and change the deformation of beams as well as the distribution of fluid pressure.

FRAMEWORK OF WIND–VEHICLE–BRIDGE INTERACTION ANALYSIS AND ITS APPLICATIONS

2013 ◽  
Vol 07 (03) ◽  
pp. 1350020 ◽  
Author(s):  
C. S. CAI ◽  
WEI ZHANG ◽  
XIANZHI LIU ◽  
WEI PENG ◽  
S. R. CHEN ◽  
...  
Keyword(s):  
Interaction Analysis ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Dynamic Responses ◽  
Future Research ◽  
Element Analysis ◽  
Long Span Bridges ◽  
Safety Issues ◽  
Wind Speeds ◽  
Moving Vehicles

Under strong winds, bridges may exhibit large dynamic responses. Wind may also endanger the safety of moving vehicles on the roadways as well as on bridges. For regular aerodynamic study of long-span bridges, traffic loads are not typically considered, assuming that bridges will be closed to traffic at high wind speeds. Therefore, bridges are usually tested in wind tunnels or analyzed numerically without considering moving vehicles on them. However, there are numerous possible scenarios under which vehicles may still be on the bridge when higher wind speeds occur. These scenarios include unexpected increase in hurricane forward speed or intensity, evacuation traffic gridlock, accidents/stalled vehicles or rainfall flooding blocking the road ahead, etc. Wind, together with vehicles, will also cause serviceability and bridge fatigue damage issues. The present study will present the framework of wind–vehicle–bridge interaction analysis and its applications, developed in the last decade by the authors' group, focused on the vehicle and bridge safety issues. It consists of the following five parts: (1) A three dimensional finite element analysis framework considering the interaction of wind, bridge and vehicles; (2) experimental facilities development and studies for both static and aerodynamic tests of bridge section models and vehicles; (3) Computation fluid dynamic (CFD) prediction of loading on vehicles; (4) performance evaluation of vehicle safety and bridge fatigue; and (5) bridge vibration mitigations. Case study will also be presented and future research needs are discussed.

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