Dynamic analysis of damages in materials is a difficult task and it is currently not known what importance different possible mechanisms carry. It is to a large extent due to the difficulty of measuring the dynamic behavior of cracks, debonds and delaminations inside material. It there exists a need to simulate the action of different mechanisms in order to understand the basic physics and possibly identify the signatures of measured vibration and acoustic signals. In this work we study vibrational responses from a specimen which has different types of non-linearities like fractures in it and understand various factors concerned with fracture location, fracture behavior and so on. After finding the fracture location and fracture size, stress intensity factors can be calculated and from them fatigue tests and other failure tests can be done.
Contents
1. Notation
2. Introduction
2.1. Thesis background
2.2. Fracture and Damage Mechanics
2.3. Damages in Heterogeneous Materials
2.4. Geometric nonlinearities
2.5. Material nonlinearities
2.5.1. Cracks
2.5.2. Debonds
2.5.3. Delaminations
2.6. Motivation to the Approach
3. Theory and concepts
3.1. Linear Elastic Fracture Mechanics
3.2. Frequency, wavelength and Time period
3.3. Mechanical waves
3.3.1. Reflection at interface
3.4. Variable Amplitude Loading
3.5. Integration Time step or Step size
3.6. Nonlinear Dynamics and Damage
3.7. Plasticity
4. Dynamic Analysis
4.1. Homogeneous material
4.1.1. Analytical Data and Calculations
4.1.2. Modeling
4.1.3. Frequency Analysis
4.1.4. Dynamic Analysis
4.1.5. Results
4.2. Homogeneous material with crack
4.2.1. Analytical Data and Calculations
4.2.2. Modeling
4.2.3. Frequency Analysis
4.2.4. Dynamic Analysis
4.2.5. Results
4.2.5.1.Homogenous material with fixed crack
4.3. Heterogeneous material
4.3.1. Analytical Data and Calculations
4.3.2. Modeling
4.3.3. Frequency Analysis
4.3.4. Dynamic Analysis
4.3.5. Results
4.4. Heterogeneous material with crack
4.4.1. Modeling
4.4.2. Frequency Analysis
4.4.3. Dynamic Analysis
4.4.4. Results
5. Conclusions
6. Further approach to work
7. References
Author: Vidya Sagar Avadutala
Source: Blekinge Institute of Technology
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