Distributed Friction Damping of Traveling Wave Vibration in Rods

2007 ◽  
Author(s):  
X. W. Tangpong ◽  
J. A. Wickert ◽  
A. Akay
Keyword(s):  
Traveling Wave ◽  
Longitudinal Vibration ◽  
Periodic Boundary Conditions ◽  
Frequency Range ◽  
Brake Rotor ◽  
Spatially Distributed ◽  
Computationally Intensive ◽  
Distributed Friction ◽  
Automotive Brake ◽  
Base Structure

A ring damper can be affixed to a rotating base structure such as a gear, an automotive brake rotor, or a gas turbine’s labyrinth air seal. Depending on the frequency range, wavenumber, and level of preload, vibration of the base structure can be effectively and passively attenuated by friction that develops along the interface between it and the damper. The assembly is modeled as two rods that couple in longitudinal vibration through spatially-distributed hysteretic friction, with each rod having periodic boundary conditions in a manner analogous to an unwrapped ring and disk. As is representative of rotating machinery applications, the system is driven by a traveling wave disturbance, and for that form of excitation, the base structure’s and the damper’s responses are determined without the need for computationally-intensive simulation. The damper’s performance can be optimized with respect to normal preload, and its effectiveness is insensitive to variations in preload or the excitation’s magnitude when its natural frequency is substantially lower than the base structure’s in the absence of contact.

Distributed friction damping of travelling wave vibration in rods

2007 ◽  
Vol 366 (1866) ◽  
pp. 811-827 ◽  
Author(s):  
Xiangqing W Tangpong ◽  
Jonathan A Wickert ◽  
Adnan Akay
Keyword(s):  
Longitudinal Vibration ◽  
Periodic Boundary Conditions ◽  
Travelling Wave ◽  
Frequency Range ◽  
Brake Rotor ◽  
Spatially Distributed ◽  
Computationally Intensive ◽  
Distributed Friction ◽  
Automotive Brake ◽  
Base Structure

A ring damper can be affixed to a rotating base structure such as a gear, an automotive brake rotor or a gas turbine's labyrinth air seal. Depending on the frequency range, wavenumber and level of preload, vibration of the base structure can be effectively and passively attenuated by friction that develops along the interface between it and the damper. The assembly is modelled as two rods that couple in longitudinal vibration through spatially distributed hysteretic friction, with each rod having periodic boundary conditions in a manner analogous to an unwrapped ring and disc. As is representative of rotating machinery applications, the system is driven by a travelling wave disturbance, and for that form of excitation, the base structure's and the damper's responses are determined without the need for computationally intensive simulation. The damper's performance can be optimized with respect to normal preload, and its effectiveness is insensitive to variations in preload or the excitation's magnitude when its natural frequency is substantially lower than the base structure's in the absence of contact.

scholarly journals Thermal expansion and fatigue properties of automotive brake rotor made of AlSi–SiC composites

2020 ◽  
Vol 6 (12) ◽  
pp. 1265d2 ◽  
Author(s):  
F M Firouz ◽  
E Mohamed ◽  
A Lotfy ◽  
A Daoud ◽  
M T Abou El-Khair
Keyword(s):  
Thermal Expansion ◽  
Fatigue Properties ◽  
Brake Rotor ◽  
Sic Composites ◽  
Automotive Brake

Seismic Hazard and Loss Analysis for Spatially Distributed Infrastructure in Christchurch, New Zealand

2016 ◽  
Vol 32 (2) ◽  
pp. 697-712 ◽  
Author(s):  
Hasan Manzour ◽  
Rachel A. Davidson ◽  
Nick Horspool ◽  
Linda K. Nozick
Keyword(s):  
New Zealand ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Regional Scale ◽  
Average Error ◽  
Loss Analysis ◽  
Spatially Distributed ◽  
Small Set ◽  
Computationally Intensive ◽  
Distributed Infrastructure

The new Extended Optimization-Based Probabilistic Scenario method produces a small set of probabilistic ground motion maps to represent the seismic hazard for analysis of spatially distributed infrastructure. We applied the method to Christchurch, New Zealand, including a sensitivity analysis of key user-specified parameters. A set of just 124 ground motion maps were able to match the hazard curves based on a million-year Monte Carlo simulation with no error at the four selected return periods, mean spatial correlation errors of 0.03, and average error in the residential loss exceedance curves of 2.1%. This enormous computational savings in the hazard has substantial implications for regional-scale, policy decisions affecting lifelines or building inventories since it can allow many more downstream analyses and/or doing them using more sophisticated, computationally intensive methods. The method is robust, offering many equally good solutions and it can be solved using free open source optimization solvers.

AlSi-SiC Composites for Automotive Brake Rotor

2020 ◽  
Vol 835 ◽  
pp. 178-185
Author(s):  
Fatma Firouz ◽  
Atef Daoud ◽  
Malak Abou El-Khair
Keyword(s):  
Solution Treatment ◽  
Stir Casting ◽  
Primary Phase ◽  
Casting Method ◽  
Sic Particles ◽  
Brake Rotor ◽  
Eutectic Si ◽  
Sic Composites ◽  
Brake Rotors ◽  
Automotive Brake

This manuscript investigates the Fabrication and Microstructure of Automotive Brake Rotor Made of AlSi-SiC Composites. This work is oriented toward fabrication of automotive brake rotors from Al-9Si and Al-12Si reinforced with 10 and 20% SiC particles using stir-casting method. The brake rotors were subjected to heat treatment. Aging behavior showed that hardness increased with the addition of SiC reinforcements by 104%, comparing to solution treatment condition. Also, the addition of SiC particles accelerates formation of precipitates. Microstructure of brake rotors made of composite revealed uniform distribution of SiC particles, primary phase (⍺-Al) and modified eutectic Si. EDX analysis showed the presence of Al, Mg and O at the interface between matrix and SiC particles.

scholarly journals A Novel Traveling Wave Sandwich Piezoelectric Transducer With Single Phase Drive: Theoretical Modeling , Experimental Validation and Application Investigation

2020 ◽  
Author(s):  
Liang Wang ◽  
Fushi Bai ◽  
Viktor Hofmann ◽  
Jiamei Jin ◽  
Jens Twiefel
Keyword(s):  
Transfer Matrix ◽  
Piezoelectric Transducer ◽  
Traveling Wave ◽  
Single Phase ◽  
Longitudinal Vibration ◽  
Experimental Results ◽  
Sandwich Composite ◽  
Driving Frequency ◽  
Mobile System ◽  
Mean Velocity

Abstract Most of traditional traveling wave piezoelectric transducers are driven by two phase different excitation signals, leading to a complex control system and seriously limiting their applications in industry. To overcome these issues, a novel traveling wave sandwich piezoelectric transducer with a single-phase drive is proposed in this study. Traveling waves are produced in two driving rings of the transducer while the longitudinal vibration is excited in its sandwich composite beam, due to the coupling property of the combined structure. This results in the production of elliptical motions in the two driving rings to achieve the drive function. An analytical model is firstly developed using the transfer matrix method to analyze the dynamic behavior of the proposed transducer. Its vibration characteristics are measured and compared with computational results to validate the effectiveness of the proposed transfer matrix model. Besides, the driving concept of the transducer is investigated by computing the motion trajectory of surface points of the driving ring and the quality of traveling wave of the driving ring. Additionally, application example investigations on the driving effect of the proposed transducer are carried out by constructing and assembling a tracked mobile system. Experimental results indicated that 1) the assembled tracked mobile system moved in the driving frequency of 19410 Hz corresponding to its maximum mean velocity through frequency sensitivity experiments; 2) motion characteristic and traction performance measurements of the system prototype presented its maximum mean velocity with 59 mm/s and its maximum stalling traction force with 1.65 N, at the excitation voltage of 500 V RMS . These experimental results demonstrate the feasibility of the proposed traveling wave sandwich piezoelectric transducer.

scholarly journals Multiobjective calibration of the MESH hydrological model on the Reynolds Creek Experimental Watershed

2010 ◽  
Vol 7 (2) ◽  
pp. 2121-2155 ◽  
Author(s):  
A. J. MacLean ◽  
B. A. Tolson ◽  
F. R. Seglenieks ◽  
E. Soulis
Keyword(s):  
Snow Water Equivalent ◽  
Model Simulation ◽  
Hydrologic Model ◽  
Simulation Accuracy ◽  
Mesh Model ◽  
Reynolds Creek ◽  
Spatially Distributed ◽  
Multiobjective Calibration ◽  
Computationally Intensive ◽  
Computational Budget

Abstract. The spatially distributed MESH hydrologic model (Pietroniro et al., 2007) was successfully calibrated and then validated for the prediction of snow water equivalent (SWE) and streamflow in the Reynolds Creek Experimental Watershed in Idaho, USA. The tradeoff between fitting to SWE versus streamflow data was assessed and showed that both could be simultaneously predicted with good quality by the MESH model. Not surprisingly, calibrating to only one objective (e.g. SWE) yielded poor simulation results for the other objective (e.g. streamflow). The multiobjective calibration problem in this study was efficiently solved via a simple weighted objective function approach and analyses showed that the approach yielded a balanced solution between the objectives. Our approach therefore eliminated the need to rely on a potentially more computationally intensive evolutionary multiobjective algorithm to approximate the entire tradeoff surface between objectives. Additional calibration experiments showed that for our calibration computational budget (2000 model evaluations), the autocalibration procedure would fail without being initialized to a model parameter set carefully determined for this specific case study. This study serves as a benchmark for MESH model simulation accuracy which can be compared with future versions of MESH.

Finite Element Simulation of an Automotive Brake Rotor With Metallic Damping Inserts

2010 ◽  
Author(s):  
Shung H. Sung ◽  
M. David Hanna ◽  
James G. Schroth
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Sound Pressure ◽  
Radiated Noise ◽  
Press Fit ◽  
Modal Damping ◽  
Brake Rotor ◽  
Radiated Sound ◽  
Automotive Brake ◽  
Element Method

A finite element method is developed for simulating the performance of an automotive brake rotor with metallic inserts that are used to dampen the vibration and radiated noise response. The metallic inserts are located in slots that are cast at the edge of the rotor circumference between the two rotor surfaces. Three different rotor configurations are evaluated: (a) an undamped solid rotor, (b) a damped rotor with an unconstrained press-fit metallic insert, and (c) a damped rotor with a constrained cast-in coated metallic insert. Comparisons of the predicted versus measured rotor surface vibration and radiated sound pressure are made to evaluate the effect of the insert and the accuracy of the finite element method. The comparisons show that significant modal damping of the rotor vibration and radiated noise can be achieved through the use of the coated metallic insert. A methodology is developed and applied to evaluate the damping of different metallic inserts and coatings from only the radiated sound pressure response.

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