Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Institution
- Publication
- Publication Type
- File Type
Articles 1 - 10 of 10
Full-Text Articles in Engineering
Vibration Based Planetary Gear Analysis And Damage Detection, Rene Sawatzky
Vibration Based Planetary Gear Analysis And Damage Detection, Rene Sawatzky
Master's Theses
With this thesis the research at the engineering department is continued, based on previous thesis projects. These projects were considering the possibility of simulation gears with rigid bodies. After researches with different emphasizes on the rigid body simulation, the gained knowledge showed limitations of the rigid body model. Gear failures are very diverse and the actual simulation technique could not represent all necessary failure modes that can occur. That led to this thesis as a research project to find a way to detect and analyze the failure modes that cannot be considered with the current rigid body approach. With the …
Mathematical Equations And System Identification Models For A Portable Pneumatic Bladder System Designed To Reduce Human Exposure To Whole Body Shock And Vibration, Ezzat Aziz Ayyad
UNLV Theses, Dissertations, Professional Papers, and Capstones
A mathematical representation is sought to model the behavior of a portable pneumatic foam bladder designed to mitigate the effects of human exposure to shock and whole body random vibration. Fluid Dynamics principles are used to derive the analytic differential equations used for the physical equations Model. Additionally, combination of Wiener and Hammerstein block oriented representation techniques have been selected to create system identification (SID) block oriented models. A number of algorithms have been iterated to obtain numerical solutions for the system of equations which was found to be coupled and non-linear, with no analytic closed form solution. The purpose …
Think Outside The Box: New Materials, Design Application, And Performance Of Railway Turnout Bearers, Sakdirat Kaewunruen
Think Outside The Box: New Materials, Design Application, And Performance Of Railway Turnout Bearers, Sakdirat Kaewunruen
Sakdirat Kaewunruen
Railway turnout systems are a main feature in railway tracks. There are two types of turnout support structures, which can be designed to be either a slab or a cluster of discrete bearers. The choice of turnout support system depends on asset management strategy of the rail operators or maintainers. This paper will focus on the discrete turnout bearer system where turnout alignments, settlement and deformation are comparatively more flexible and retrievable by routine ballast tamping. It embraces the consideration of new materials for use as a turnout bearer. Traditional bearer materials are timber, steel, and concrete. Recent developments have …
The Influence Of Gaps On The Frequency Response Of A Beamspring Contact System, Wenbin Zhang
The Influence Of Gaps On The Frequency Response Of A Beamspring Contact System, Wenbin Zhang
Open Access Theses
Some mechanical systems with gaps such as in disc brakes and Cardan joints exhibit nonlinearity under certain load conditions, which is unpredictable and highly sensitive to initial conditions. Previous studies were mainly focused on either a single-degree-of-freedom (DOF) system or a flexible beam with uniform elastic foundation. The analysis of this thesis is a combination of these two where gaps are first introduced to a flexible beam model. A model of a beam resting on compliant foundation with gaps has been developed and analyzed. The assumed modes method is used to derive the equations of motion (EOM's) for the system. …
Review Of Live Loads Due To Human Movements, William Saul, Christopher Tuan
Review Of Live Loads Due To Human Movements, William Saul, Christopher Tuan
Christopher Y. Tuan
Present U.S. structural engineering practice assumes that live load components due to human occupancy and human movements for the design of assembly structures, such as grandstands, can be represented as statically applied uniform or line loads. A review of code values and procedures reveals a history of theoretical, experimental, empirical, and practical developments and events that provide insight into their sources and meanings. The mechanisms by which they have been implemented should prove to be interesting and informative to the design engineer and others concerned with the modernization of codes. The designer is provided with a perspective of a complex …
Loads Due To Spectator Movements, Christopher Tuan, William Saul
Loads Due To Spectator Movements, Christopher Tuan, William Saul
Christopher Y. Tuan
Typical spectator movements were simulated by persons individually on a force platform with which dynamic force components were measured. Impulsive loadings are produced by movements such as rising, sitting, or jumping off the floor, while continuous loadings are generated in repetitive motion such as swaying, bending and straightening knees repetitively in place, jumping or dancing. Descriptive parameters derived from statistical and spectral studies of the load samples are presented. In particular, the vertical components of the impulsive loadings are modeled as random forcing functions, and a narrow‐band live load spectrum is proposed for checking potential resonant response of a structure …
Understanding Chassis Inputs From The Rear Suspension Of A Snowmobile, Jamie L. Kleinendorst
Understanding Chassis Inputs From The Rear Suspension Of A Snowmobile, Jamie L. Kleinendorst
Dissertations, Master's Theses and Master's Reports - Open
Today’s snowmobile industry faces great challenges in the field of noise & vibration. The area of main concern is the pass-by noise restriction defined by the Society of Automotive Engineers (SAE) test standard J192, with a maximum sound pressure level of 78 dB(A) being required by many states and national parks. To continue meet or beat this requirement without effecting machine performance, a deeper understanding of the sound transfer paths is required. This thesis examines the transfer paths created by the tunnel, rear suspension, drive shaft, and rubber composite track, with the primary source being suspension input through the ground. …
Investigating The Optimal Passive And Active Vibration Controls Of Adjacent Buildings Based On Performance Indices Using Genetic Algorithms, Muhammad N. S Hadi, Mehmet Uz
Investigating The Optimal Passive And Active Vibration Controls Of Adjacent Buildings Based On Performance Indices Using Genetic Algorithms, Muhammad N. S Hadi, Mehmet Uz
Faculty of Engineering and Information Sciences - Papers: Part A
This study proposes the optimal passive and active damper parameters for achieving the best results in seismic response mitigation of coupled buildings connected to each other by dampers. The optimisation to minimise the H2 and H- norms in the performance indices is carried out by genetic algorithms (GAs). The final passive and active damper parameters are checked for adjacent buildings connected to each other under El Centro NS 1940 and Kobe NS 1995 excitations. Using real coded GA in H- norm, the optimal controller gain is obtained by different combinations of the measurement as the feedback for designing the control …
A Novel Magnetorheological Elastomer Isolator With Negative Changing Stiffness For Vibration Reduction, Jian Yang, Shuaishuai Sun, Haiping Du, Weihua Li, Gursel Alici, Huaxia Deng
A Novel Magnetorheological Elastomer Isolator With Negative Changing Stiffness For Vibration Reduction, Jian Yang, Shuaishuai Sun, Haiping Du, Weihua Li, Gursel Alici, Huaxia Deng
Australian Institute for Innovative Materials - Papers
Magneto-rheological elastomers (MREs) have attracted notable credits in the development of smart isolators and absorbers due to their controllable stiffness and damping properties. For the purpose of mitigating unwanted structural and/or machinery vibrations, the traditional MRE-based isolators have been generally proven effective because the MR effect can increase the stiffness when the magnetic field is strengthened. This study presents a novel MRE isolator that experienced reduced stiffness when the applied current was increased. This innovative work was accomplished by applying a hybrid magnet (electromagnet and permanent magnets) onto a multilayered MRE structure. To characterise this negative changing stiffness concept, a …
Topographical Optimization Of Structures For Use In Musical Instruments And Other Applications, William Brandon Kirkland
Topographical Optimization Of Structures For Use In Musical Instruments And Other Applications, William Brandon Kirkland
All ETDs from UAB
Mallet percussion instruments such as the xylophone, marimba, and vibraphone have been produced and tuned since their inception by arduously grinding the keys to achieve harmonic ratios between their 1st, 2nd, and 3rd transverse modes. In consideration of this, it would be preferable to have defined mathematical models such that the keys of these instruments can be produced quickly and reliably. Additionally, physical modeling of these keys or beams provides a useful application of non-uniform beam vibrations as studied by Euler-Bernoulli and Timoshenko beam theories. This thesis work presents a literature review of previous studies regarding mallet percussion instrument design …