The Effects of Frequency and Pivot Flexibility on the Dynamic Properties of Tilting-Pad Journal Bearings | Chapter 04 | Research Developments in Science and Technology Vol. 5

 Tilting-pad journal bearings (TPJB) dynamic modelling must take into account the frequency dependency of the dynamic parameters, according to tribologists. Blades, impellers, and seals in industrial compressors, turbines, and other rotating devices cause instability, resulting in dominating vibratory frequencies that are often significantly different from rotational frequency. Though the literature has supplied relevant methodologies and numerical data, the design community does not have a complete grasp of the physics of TPJB frequency dependence, and theorists and experimentalists frequently disagree. This study is based on a single-pad, two-degree-of-freedom model that establishes a foundation for comprehending the various geometries and operating circumstances associated with frequency dependence for a complete bearing. The analytical results show that both stiffness and stiffness. The frequency dependency is principally connected with the pad rotational damping and the flexibility of the pivot contact region that provides support for the pad, as shown by and damping coefficients. This research aims to give insight into the role of pivot flexibility in conjunction with fluid film in order to assist analysts in reaching a consensus between theory and experiment.

This article is a revised and enlarged version of a paper delivered at the ASME 2019 Turbo Expo, which took place from June 17 to 21 in Phoenix, Arizona. The work was titled "On the Frequency Dependency of Tilting-Pad Journal Bearings" and has the number GT2019-90195.

Author(S) Details

Laurence F. Wagner
Rotor Bearing Solutions Intl. LLC, 5211 Mountainview Rd., Winston Salem, NC 27104, USA.

Paul E. Allaire
Rotor Bearing Solutions Intl. LLC, 5211 Mountainview Rd., Winston Salem, NC 27104, USA.

View Book:- https://stm.bookpi.org/RDST-V5/article/view/6865

Experimental Modeling of Mechanical Characteristics in Living Elastic Bodies | Chapter 10 | New Visions in Science and Technology Vol. 10

Experimental modelling of mechanical properties in living elastic entities is one of the research goals.

Methods: Research into the acoustic and mechanical properties of the force of live bodies led to the conclusion that acoustic fields can have a detailed influence on the bodies of hazardous insect larvae. The mass, stiffness, and resonance frequency of these bodies must all be known.

Results: A method has been devised for identifying the resonance frequency of the larvae of hazardous insects. The research is based on the notion that the larva's body is similar to that of a homogeneous cylindrical shaft. The larvae's organs are placed in a specific apparatus. The modulus of elasticity and rigidity of the larva's body were calculated after the experimental data was processed.

Author(S) Details

Galyna I. Sokol
Oles Honchar Dnipro National University, Ukraine.

Tatyana L. Savchuk
Oles Honchar Dnipro National University, Ukraine.

Danylo O. Snobko
Oles Honchar Dnipro National University, Ukraine.

View Book:- https://stm.bookpi.org/NVST-V10/article/view/4891

Studies on the Stiffness Properties of Pinus caribaea Round Timber Logs | Chapter 10 | New Ideas Concerning Science and Technology Vol. 1

 

The current study evaluated the estimate of the longitudinal (E) and transversal (G) elasticity modulus of the round structural beams of Pinus caribaea timber in order to verify whether the relationship between the two modules of the Brazilian Standard ANBT NBR 7190 is actually reliable for this species of wood. Twenty pieces of green wood were tested with an average length, diameter and conicity of 750 cm, 30 cm and 4 percent , respectively, to conduct such an assessment. At three points of each object, two static bending tests were applied, being nondestructive and using distinct distances between supports. The relationship of length and diameter relationship (L / d) was set to be equal to 24 in the first test; however, it was set to 12 in the second test. A successive use of the Timoshenko beam theory equation, which takes into account the shearing stress effect on displacement measurements, calculated the elasticity moduli. The results of the tests were connected by means of the least square evaluation process. G = E/43 was the relation found between elasticity moduli.

Author(s) Details

André Luis Zangiácomo
Department of Engineering, Federal University of Lavras, Lavras/MG, Brazil.

Vinicius Borges de Moura Aquino
Araguaia Engineering Institute, Federal University of Southern and Southeastern Pará (UNIFESSPA), Santana do Araguaia/PA, Brazil.

André Luis Christoforo
Department of Civil Engineering (DECiv), Federal University of São Carlos, São Carlos/SP, Brazil.

Francisco Antonio Rocco Lahr

Department of Structural Engineering, São Carlos School of Engineering of São Carlos, University of São Paulo (USP), São Carlos/SP, Brazil.

View Book :- https://bp.bookpi.org/index.php/bpi/catalog/book/308