Analysis Comparative of Methods to Evaluate Consolidation Mechanisms in Plastic and Viscoelastic Materials Used as Direct Compression Excipients

The consideration of damping in structural dynamics problems is an important and non-trivial problem. Its complexity, not least, is due to the need to set the correct data for the materials used and to select a model suitable for analysis. In this paper, we consider some models of viscoelastic materials from the point of view of the possibilities of using these models for the harmonic analysis of the damping properties of various materials in the linear region of elastic deformations. The proposed analysis is based on the use of parameters of viscoelastic materials specified in the form of coefficients of the differential equation of small forced vibrations. It is shown that the considered models are characterized by a different frequency dependence of the parameters of the simulated materials. This opens up the possibility of combining the model with the frequency characteristics of its parameters, approaching the frequency characteristics of the parameters of the studied viscoelastic materials.

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Integrated Dynamic Characterization of Thermorheologically Simple Viscoelastic Materials Accounting for Frequency, Temperature, and Preload Effects

Materials ◽

10.3390/ma12121962 ◽

2019 ◽

Vol 12 (12) ◽

pp. 1962 ◽

Cited By ~ 2

Author(s):

Eduardo G. Olienick Filho ◽

Eduardo M. O. Lopes ◽

Carlos A. Bavastri

Keyword(s):

Vibration Isolation ◽

Dynamic Properties ◽

Linear Optimization ◽

Optimization Technique ◽

Integrated Approach ◽

Viscoelastic Materials ◽

Materials Used ◽

Traditional Approaches ◽

Frequency Temperature

In vibration insulation projects, a parameter affecting the dynamic properties of the viscoelastic materials is the previous static load acting on the supports, denominated here as the ‘preload’. Most of the currently-used methodologies obtain the dynamic properties by considering only the effects of temperature and frequency. The additional effect of preload can be added to the usual methodologies by employing the hyperelastic theory developed by Mooney–Rivlin. The current work proposes an integrated approach to characterize thermorheologically simple viscoelastic materials, including the preload effect along with the influence of temperature and frequency. The proposed method uses a hybrid optimization process, combining a genetic algorithm (GA) and a non-linear optimization technique—named ‘simplex’—in an inverse problem structure applied to all experimental data at hand. A set of samples of elastomer BT-806 55 (butyl rubber) was tested at various temperatures, frequencies, and preloads. The comparison between the results of the present methodology and traditional approaches to a variation in the dynamic properties at all frequencies and temperatures for a constant vibration amplitude. The present results prove that the proposed methodology is a viable alternative to represent the dynamic properties of materials used in vibration isolation.

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Using of Recycled Materials to Protect the Working and Natural Environment by Reducing Noise and Vibration

Strojnícky casopis – Journal of Mechanical Engineering ◽

10.2478/scjme-2020-0031 ◽

2020 ◽

Vol 70 (2) ◽

pp. 197-211

Author(s):

Žiaran Stanislav ◽

Šooš Ľubomír ◽

Chlebo Ondrej

Keyword(s):

Frequency Spectrum ◽

Natural Environment ◽

Mechanical Systems ◽

Experimental Results ◽

Theoretical Knowledge ◽

Sound Waves ◽

Viscoelastic Materials ◽

Recycled Materials ◽

Noise And Vibration ◽

Materials Used

AbstractThe aim of the article is to define the conditions for the use of recycled resilient materials in the reduction of noise and vibration as an integral part of the mounting and installation of mechanical systems in the work and natural environment. Based on the frequency spectrum, the vibro-isolation efficiency of the vibro-isolators and the viscoelastic materials used is analysed. The solution of this problem is based on the theoretical knowledge and methodology of the transmission of vibration-sound waves. The measurements of the vibration at the sources and along the path of transmission were performed for different recycled materials to compare experimental results with theory.

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Robust Phase Velocity Dispersion Estimation of Viscoelastic Materials Used for Medical Applications Based on the Multiple Signal Classification Method

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control ◽

10.1109/tuffc.2018.2792324 ◽

2018 ◽

Vol 65 (3) ◽

pp. 423-439 ◽

Cited By ~ 9

Author(s):

Piotr Kijanka ◽

Bo Qiang ◽

Pengfei Song ◽

Carolina Amador Carrascal ◽

Shigao Chen ◽

...

Keyword(s):

Phase Velocity ◽

Velocity Dispersion ◽

Signal Classification ◽

Classification Method ◽

Medical Applications ◽

Viscoelastic Materials ◽

Multiple Signal Classification ◽

Multiple Signal ◽

Phase Velocity Dispersion ◽

Materials Used

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EXPERIMENTAL ANALYSIS OF DAMPING PROPERTIES OF VISCOELASTIC MATERIALS

Acta Metallurgica Slovaca ◽

10.36547/ams.27.2.896 ◽

2021 ◽

Vol 27 (2) ◽

pp. 63-67

Author(s):

Piotr Łabuński ◽

Lucjan Witek

Keyword(s):

Free Vibrations ◽

Butyl Rubber ◽

Experimental Investigations ◽

Steel Beam ◽

Damping Properties ◽

Viscoelastic Materials ◽

Rubber Layer ◽

Acceleration Sensors ◽

Materials Used ◽

Half Power

This study presents results of an experimental investigations of the materials used in passive damping vibrations. The main purpose of this paper was to examine the damping properties of selected viscoelastic materials (VEM), using the modal analysis. In presented analysis three configurations of specimens were considered. At first, the separated steel beam was analyzed. As results of this analysis, the frequencies and amplitudes of the beam during resonance were obtained. In next part of the work the modified specimen was investigated. In this modification the bitumen-based material (as a damper) was fixed to the surface of the beam. This method is known as free layer damping (FLD) treatment. In last configuration, the butyl rubber layer was connected to the steel beam. Using the Unholtz-Dickie UDCO-TA250 electrodynamic vibration system, the natural frequencies and amplitudes of free vibrations for all examined specimens were obtained. The vibration amplitude of the beam was measured using piezoelectric acceleration sensors. In order to define the damping capabilities of both the bitumen based material and the butyl rubber, the relative amplitude of specimens and the loss factor using half-power bandwidth method were calculated.

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Deformation Replication

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100068394 ◽

1970 ◽

Vol 28 ◽

pp. 280-281

Author(s):

J. Temple Black

Keyword(s):

Cutting Speed ◽

Machining Process ◽

Depth Of Cut ◽

Rake Face ◽

Orthogonal Machining ◽

Aluminum Chips ◽

Before And After ◽

Materials Used ◽

Glass Knife ◽

Very High

Tool materials used in ultramicrotomy are glass, developed by Latta and Hartmann (1) and diamond, introduced by Fernandez-Moran (2). While diamonds produce more good sections per knife edge than glass, they are expensive; require careful mounting and handling; and are time consuming to clean before and after usage, purchase from vendors (3-6 months waiting time), and regrind. Glass offers an easily accessible, inexpensive material ($0.04 per knife) with very high compressive strength (3) that can be employed in microtomy of metals (4) as well as biological materials. When the orthogonal machining process is being studied, glass offers additional advantages. Sections of metal or plastic can be dried down on the rake face, coated with Au-Pd, and examined directly in the SEM with no additional handling (5). Figure 1 shows aluminum chips microtomed with a 75° glass knife at a cutting speed of 1 mm/sec with a depth of cut of 1000 Å lying on the rake face of the knife.

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