Polymers for Vibration Damping Applications

Bikash C. Chakraborty, Debdatta Ratna

• Publisher: Elsevier
• Year: 2020
• Print ISBN: 9780128192528
• eBook ISBN: 9780128192535
• Topic: Technology & Engineering
• Subtopic: Industrial & Technical Chemistry
• Index: Technology & Engineering

Polymers for Vibration Damping Applications is a detailed guide on the use of polymers and polymer composites for vibration and shock damping. The book begins with two chapters that introduce the fundamentals of both vibration and shock damping. The next part of the book presents in-depth coverage of polymeric materials for vibration damping, including viscoelastic properties, design of polymer systems, and modes and applications. Finally, measurement techniques are discussed in detail. Throughout the book, the different perspectives of materials and engineering are considered, and both mathematical and conceptual approaches are used. This is an essential resource for all those looking to understand the application of polymers for vibration damping, including researchers, scientists and advanced students in polymer science, plastics engineering, materials science and mechanical engineering, as well as engineers and R&D personnel in the automotive, marine, defense and construction industries. - Equips the reader with a complete, fundamental understanding of vibration and shock damping - Explains the viscoelastic properties, design and applications of polymeric materials for vibration damping applications - Includes cutting-edge research on the use of polymers for advanced civil and defense applications

Chapter 1

Fundamentals of vibration damping

Abstract

This chapter introduces simple harmonic motion (SHM), sinusoidal dynamic displacement, velocity, acceleration, and natural frequency of a body. Equations related to undamped, underdamped, critically damped, and overdamped systems in free vibration are provided with graphs. Physical representations and equations of an undamped and damped body for single-degree of freedom (SDOF) are illustrated for forced vibration. The vibration transmissibility of a machine and foundation against frequency are expressed with examples of different viscoelastic materials (VEM) at several modes. Method of calculating system loss factor from the resonance peak is elaborated. A table summarises the important parameters related to vibration and damping. Two examples of numerical calculation of damped forced vibration are provided. Method of selection and tailoring of a VEM for designing vibration mount is described in an example and an Appendix A. Test methods for recording responses of both the machine and base excitation are given in brief.

Keywords

Vibration; Natural frequency; Undamped; Damped; Single-degree of freedom (SDOF); Loss factor; Transmissibility; Modes; Compression

Abbreviations

DSA dynamic signal analyser

FFT Fast Fourier Transform

SHM simple harmonic motion

SDOF single degree of freedom

SONAR sound navigation and ranging

VEM viscoelastic material

Symbols with units

A amplitude of vibration (displacement) (m)

a acceleration (m/s²)

C ₁, C₂ constants of integration

E modulus of elasticity (N/m² (Pa))

F force (N)

f frequency (Hz)

g acceleration due to gravity (9.81 m/s²)

h height or thickness (m)

i imaginary quantity (=$\sqrt{-1}$

)

k stiffness (spring constant) (N/m)

m mass (kg)

n mode number (dimensionless)

P power (W or J/s)

Q quality factor (dimensionless)

R ratio of vibration intensities (dimensionless)

T time period of oscillation (s)

t time (s)

u displacement (m)

v velocity (m/s)

W weight (N)

δ deflection (m)

ɛ transmissibility (dimensionless)

η viscoelastic loss factor (dimensionless)

Δ logarithmic decrement (dimensionless)

φ phase angle (radian)

λ damping coefficient (N s/m)

ω angular frequency (rad/s)

ξ damping factor (dimensionless)

1.1 Vibration

Vibration is a very common phenomenon. In fact, everything vibrates—it is only the question of intensity and its effect on man, machine, and environment that can be a concern to the mankind. Vibration may be defined as a time-dependent movement of a particle around its equilibrium position. The dynamic (time-dependent) displacement is either uniform in timescale (harmonic) or nonuniform (nonharmonic). However, the difference in oscillation and vi...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Preface
• Chapter 1: Fundamentals of vibration damping
• Chapter 2: Fundamentals of shock damping
• Chapter 3: Viscoelasticity
• Chapter 4: Design of polymer systems for vibration damping
• Chapter 5: Mode of damping
• Chapter 6: Experimental techniques and instruments for vibration damping
• Index