Title Page
ABSTRACT
ABSTRACT (KOREAN)
Contents
CHAPTER 1. INTRODUCTION 14
CHAPTER 2. THEORY 20
2.1. Vibration transmissibility 20
2.2. Shape factor 25
2.3. Time-temperature superposition (TTS) principle 27
CHAPTER 3. MATERIALS AND METHODS 28
3.1. Materials 28
3.2. Polymer specimen preparation 28
3.3. Density (internal void) and surface morphology measurement 29
3.4. Dynamic mechanical analysis 32
3.5. Vibration testing 32
CHAPTER 4. RESULTS AND DISCUSSIONS 34
4.1. Mechanophysical characterization 34
4.2. Viscoelastic constitutive model for dynamic modulus vs. frequency 38
4.3. Dynamic modulus vs. shape factor 47
4.4. Experimental verification 52
CHAPTER 5. CONCLUSIONS 57
REFERENCES 60
Table 2.1. Comparison of various viscoelastic constitutive models (Maxwell model, Kelvin-Voigt model, Generalized Maxwell (GM) model, Standard liner solid (SLS) model, and... 23
Table 2.2. Dynamic modulus of various viscoelastic constitutive models (Maxwell model, Kelvin-Voigt model, Generalized Maxwell (GM) model, Standard liner solid (SLS) model,... 24
Table 3.1. Summary of the fabrication conditions used for the preparation of polymer plates made of PSR, SR, and PDMS. 31
Table 4.1. Summary of the averaged R² values of viscoelastic constitutive models in ascribing the dependence of the dynamic modulus master curves of PSR, SR, and PDMS... 41
Table 4.2. Summary of the parameter values of the FDSLS model used in describing the dependence of the dynamic modulus master curves on frequency for 3 viscoelastic polymers. 42
Table 4.3. Summary of the values of the parameters associated with the proportionality constants, showing the relation between proportionality constants and shape factor for 3... 51
Fig. 1.1. Vibration transfer in viscoelastic polymers. (a) Vibration transfer characteristics of viscoelastic polymer plates. Viscoelastic polymer plates transmit vibrational excitations... 19
Fig. 2.1. SDOF damped system subjected to harmonic base excitation. (a) Lumped spring-mass-dashpot (Kelvin-Voigt) system. (b) SDOF damped system made of viscoelastic... 22
Fig. 3.1. Specimen preparation and experimental set-up. (a) Preparation of viscoelastic polymer plates (b) Density measurement. (c) Surface roughness characterization of... 30
Fig. 4.1. Mechanophysical characterization of viscoelastic polymer plates. (a) Optical images of PSR, SR, and PDMS plates with different thicknesses of 0.4, 0.5, 0.6, 0.7, 0.8,... 36
Fig. 4.2. Output voltage vs. frequency of an accelerometer mounted on an exciter using diverse mounting methods such as cyanoacrylate adhesive (401, Loctite (Germany)),... 37
Fig. 4.3. Construction of the storage modulus master curve of viscoelastic polymers using the TTS principle. (a-c) Storage modulus vs. frequency (d-f) Time-temperature master curve. 43
Fig. 4.4. Construction of the loss modulus master curve of viscoelastic polymers using the TTS principle. (a-c) Loss modulus vs. frequency (d-f) Time-temperature master curve 44
Fig. 4.5. Comparison of a set of viscoelastic constitutive models in describing the frequency-dependent dynamic modulus of viscoelastic polymers. Storage modulus, loss... 45
Fig. 4.6. A systematic method for predicting the low-pass filtering characteristics of viscoelastic polymer plates, based on the fundamentals of viscoelastics, solid polymer... 46
Fig. 4.7. Dynamic modulus vs. shape factors for viscoelastic polymer plates. (a) Displacement transmissibility of PSR (left), SR (center), and PDMS (right) plates with... 50
Fig. 4.8. Experimental verification of the accuracy of the proposed model in estimating the low-pass filtering characteristics of viscoelastic polymer plates. (a) Displacement... 56