The students attending this course gain a fundamental understanding of Structural Integrity and the Damage Tolerance-based design of metallic and composite structures. They will acquire knowledge of damage initiation, propagation and fracture mechanisms as well as the concept of stress intensity factors and their experimental determination. The course will also solidify their understanding of the principles of residual strength and critical failure load in metallic and composite materials and explore the behavior of damaged structures under complex loading conditions. Furthermore, they will investigate fatigue fracture in metallic and composite materials through life prediction models and learn to apply the damage tolerance design methodology. Finally, they will be introduced to numerical simulation methods for analyzing damage propagation in metallic and composite materials from a structural integrity standpoint.

The learning outcomes of this course correspond to the descriptive indicator 8, according to the European Qualifications Framework.

COURSE CONTENT

Introduction to damage concepts and failure mechanisms in metallic and composite materials. The concept of residual strength for metallic and composite materials. Linear fracture mechanics theories, stress intensity factor analytical and numerical approaches for its determination. Experimental techniques for determining the critical stress intensity factor. Non-linear fracture mechanics, J-Integral concept and the crack tip opening displacement as failure criteria.

Basic principles of fail-safe, safe-life and damage tolerance design methods, the role of Non-Destructive Inspection methods.

Failure criteria in metallic materials. Crack propagation criteria, fatigue fracture and fatigue life prediction models for structural components, crack retardation models. The philosophy of Damage Tolerance-based design in composite materials, failure modes and criteria, fiber/matrix failure, delamination, Barely Visible Impact Damage (BVID), properties degradation. Simulation of damage propagation and residual strength calculation for metallic and composite structures using the Finite Element Method. Example and application of the damage tolerance design approach.

Το άρθρο Structural Integrity and Damage Tolerance εμφανίστηκε πρώτα στο MEAD.

1. Finite Difference Method: Classification of partial differential equations. Construction of finite difference approximations. Discretization of first and second order derivatives. Temporal discretization. Explicit and implicit numerical schemes. Boundary conditions.
2. Properties of Numerical Methods: Consistency condition. Truncation error. Stability condition. Convergence of numerical schemes.
3. Iterative Methods: Solving systems of equations.
4. Numerical methods for ordinary differential equations: Linear multistep methods. Runge-Kutta methods.
5. Programming and implementation of computational methods.

LEARNING OUTCOMES

The learning outcomes upon successful completion of the course are the following:

• Learning: The students comprehend the basic principles of computational fluid dynamics and can employ numerical methods for the prediction of flow fields.
• Skills: The students will develop skills in solving problems in aerodynamics and fluid mechanics using computer and programming.

Το άρθρο Computational Fluid Dynamics εμφανίστηκε πρώτα στο MEAD.

The content of the course is not specified due to its nature – depended on the internship placement.   The number of the internship placements are assured by the Department via its synergies with public and private industrial enterprises.

LEARNING OUTCOMES

• Ability for students to get in touch with workplaces, acquire new knowledge, participate actively in teamwork and decision making, develop their skills, participate in the design and completion of projects and generally gain work experience.
• Contribution of internships to strengthen the interconnection of educational institutions with the market and development of networking – partnerships.
• Promote modern methods for developing young entrepreneurship
• Qualitative evaluation of the actions so far and the next actions and contribution to improving the career prospects of the students

Το άρθρο Industrial Internship (Aeronautics Engineering) εμφανίστηκε πρώτα στο MEAD.

Basic engine types, operating principles, plants, components and operation characteristics of Gas Turbine (GT) systems. Ideal cycles, Brayton cycle-variants, improvements, shaft power and propulsion cycle analysis and calculations, turboprop, turbofan, turbojet, scramjet, turborocket, thrust augmentation, jet noise suppression. Analysis of turbomachines, flow equations within passages, the Euler equation, velocity triangles, compressibility, nozzles, non-dimensional quantities, efficiencies. Axial compressors and turbines mean pitch line analysis, empirical theories, blade design, degree of reaction, vortex theory, three-dimensional flow, calculation of stage performance, multi-staged systems, the cooled turbine, centrifugal compressors. Combustion chamber systems, flow and fuel configurations, the combustion process, basic sizing and initial design, cooling flow arrangements, pattern factor estimation, practical aspects. Component performance characteristics, prediction of performance, off-design operation, the gas generator, part-load operation and component matching procedures, issues on unstable operation, performance maps, initial sizing and design of a current production turbofan engine.

LEARNING OUTCOMES

The learning outcomes expected by the end of the course for the students are:

• Apply basic fluid mechanic and thermodynamic principles to understand how gas turbine engines operate.
• Develop ability to analyze and predict the cycle performance of gas turbine engines.
• Learn the components of gas turbine engines and their purpose. Understand how the performance of individual components contributes to the overall performance of the engine.
• Learn how to analyze and predict the performance of individual gas turbine engine components
• Develop skills in applying knowledge of gas turbine engine principles in designing components

or systems used in process engineering, transport and the power generation industry.

Το άρθρο Theory and Technology of Gas Turbines εμφανίστηκε πρώτα στο MEAD.

Stress and strain analysis of statically indeterminate multi-cell beams, basic concepts of fracture mechanics and their application in structural integrity. Certification and specifications related to structures. Analysis of connections and cutouts. Rings and frames. Buckling Problems of beams and thin –walled plates, local buckling phenomena and post-buckling behavior. Complex and unconventional aerospace structures. Riveted, bolted and adhesive joints of structural parts and components. Aeroelasticity, focusing on aircraft wings.

Το άρθρο Special Topics in the Analysis of Aircraft Stuctures εμφανίστηκε πρώτα στο MEAD.

The Nature of Composite Materials: Polymer Matrices: Ways of Classifying Polymers. Thermosets and Thermoplastic Polymers. Polymer morphology. Microstructure. Effect of Deformation on Polymer Morphology. Engineering Plastics. Composite materials. Structural Foam. Elastomers. Polymeric Mixtures. Liquid Polymeric Crystals. Typical Characteristics of Some Important Plastics. The Modern Technology of Plastics and Composite Materials – Possibilities and Prospects in the Greek Industry. Manufacturing technologies for polymers and composites.

Properties and Applications of Engineering Thermoplastics. Mechanics of Materials. Mechanical Behavior of Polymers: Stress-strain relations. Basic Equations and Theory of 2D Elasticity. Field equations. The 2D Elasticity Problem. Elastic and Viscoelastic Behavior. Creep in Polymers. Mathematical formulation of the creep problem. Reinforcing Fiber: Fiber Types. Continuous Fibers. Chopped fibers. Woven fabric reinforcements. Mat type reinforcements. Fiber Length Distribution. Fiber Orientation distribution. Voids. Lamina and Laminates. Fiber-Matrix Interface: Two Materials Adhesion. Elastic Behavior of Fiber reinforced Composite Materials: Elastic Properties of One Layer with Parallel Fibers. Elastic Properties of One Layer with Long Fibers and Random Orientation. Distribution of stress and strain along a single Fiber. Elastic Properties of Short Fiber Composite Materials. Definition of Damage in Composites. Interaction Between Cracks and Fiber. Fiber pull-out. Micro-mechanical models for the along the fiber and normal to the fiber direction. Shear Properties.

LEARNING OUTCOMES   

Understanding of the properties of composite materials as a basis for the improvement of the properties, manufacturing processes and design of products made from these materials. Although the emphasis is on the properties of the composite materials as a whole, a knowledge is required of the properties of the individual components: the fiber, the matrix and the interface between the fiber and the matrix. Students also understand the essence of composite materials technology which is, the ability to put strong stiff fibers in the right place, in the right orientation with the right volume fraction. Implicit in this approach is the concept that in making the composite material one is also making the final product. At first, the student learn about the classification and definition of composite materials as well as about the relation between composite materials and more traditional engineering materials and the manufacturing routes for products made from composite materials. Next, students proceeds to the properties of the fibers and matrices and their relation to microstructure and processing conditions. The concept of the fiber-matrix interface and the methods of measuring the bond strength are also presented to the students. Next, the geometrical aspects of composites with particular reference to the characterization of fiber volume fraction, fiber length distribution, fiber orientation in 2D and 3D, void content, etc. is presented to the students. Next to this, the students learn about the elastic properties of a UD lamina and comparisons between theoretical predictions and experimental results of different fiber-resin systems are given. Finally, the elastic properties of a laminate is studied and presented using classical lamination theory. Students also learn about short fiber composites, particulates as well as hybrid composites. A series of lectures is also devoted to the dynamic mechanical behavior of composites, thermal and mechanical fatigue, water absorption, fracture mechanics and crack propagation and a number of other of special topics which are updated each year.

Το άρθρο Introduction to Composite Materials εμφανίστηκε πρώτα στο MEAD.

1. Introduction to rotating machinery diagnostics and prognostics – Basic principles and problems
2. Data acquisition
3. Signal and non-parametric processing
4. Time domain rotating machinery diagnostics
5. Frequency domain rotating machinery diagnostics
6. Rotating machinery prognostics
7. Applications and laboratory testing

LEARNING OUTCOMES 

One of the objectives of this course is for the student to develop the following abilities / skills:

a) data and information search, analysis and synthesis, using corresponding technologies,

b) adapting to new environments

c) decision making

d) independent work

e) working in an interdisciplinary environment

f) evaluation and self-evaluation

g) encouraging free, creative and deductive thinking

Το άρθρο Machninery Diagnostics and Prognostics εμφανίστηκε πρώτα στο MEAD.

1. Introduction to stochastic signals and systems
2. Fundamental notions of stochastic signals in the time domain
3. Non-parametric estimation of stochastic signals in the time domain
4. Fundamental notions of stochastic signals in the frequency domain
5. Non-parametric estimation of stochastic signals in the frequency domain
6. Theory of stationary and linear stochastic signals and systems
7. Theory and properties of parametric ARMA models
8. ARMA models originating from the sampling of continuous time models
9. Introduction to non-stationary and seasonal stochastic signals
10. Theory of optimal prediction
11. Identification, estimation, and validation of stochastic parametric models
12. Introductory remarks on vector stochastic signals

LEARNING OUTCOMES

The course constitutes a comprehensive introduction into discrete-time stochastic signals and systems, with reference to random vibration. Upon successful completion of the course the student will be in position to:

• Understand the form and basic notions of stationary stochastic signals and systems in the time and frequency domains
• Appreciate their applications in mechanical & aeronautical engineering, as well as in other scientific disciplines
• Mathematically describe stationary, and certain non-stationary, stochastic signals
• Comprehend the basic notions of estimation, as well as the estimation of mathematical models of stochastic signals in the time and frequency domains
• Thoroughly analyze mathematical models for stationary stochastic signals and systems in the time and frequency domains
• Relate the mathematical models to underlying physical systems and their properties
• Perform stochastic signal prediction
• Validate an estimated model
• Model and analyze stationary stochastic signals and systems from the engineering practice using realizations and proper software (such as MATLAB/SIMULINK, R)

Το άρθρο Stochastic Signals and Systems εμφανίστηκε πρώτα στο MEAD.