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Dr. Wang Xingbo Dr. Wang Xingbo Email: [email protected] Email: [email protected] QQ:168731668 QQ:168731668 Homepage: wxbstudio.home4u.china.com Homepage: wxbstudio.home4u.china.com Fall Fall 2005 2005 Mathematical & Mechanical Mathematical & Mechanical Method in Mechanical Engineering Method in Mechanical Engineering

Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

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Mathematical & Mechanical Method in Mechanical Engineering. Dr. Wang Xingbo Email: [email protected] QQ:168731668 Homepage: wxbstudio.home4u.china.com Fall , 2005. Mathematical & Mechanical Method in Mechanical Engineering. Motivation of This Course. - PowerPoint PPT Presentation

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Page 1: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

Dr. Wang XingboDr. Wang XingboEmail: [email protected]: [email protected]

QQ:168731668QQ:168731668Homepage: wxbstudio.home4u.china.comHomepage: wxbstudio.home4u.china.com

FallFall ,, 20052005

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Page 2: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1.1. Mechanical Engineering is being a subject of Mechanical Engineering is being a subject of sciencescience

2.2. Development of cross &Multi-subjects,especially Development of cross &Multi-subjects,especially Computer science

3.3. Future requirements of persons in research Future requirements of persons in research workwork

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Motivation of This CourseMotivation of This Course

Page 3: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1.1. To show idea of scientific methodologyTo show idea of scientific methodology

2.2. To introduce fundamental methodsTo introduce fundamental methods

3.3. To agitate the creative competenceTo agitate the creative competence

4.4. To dig out one or more elitesTo dig out one or more elites

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Purpose of the coursePurpose of the course

Page 4: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1.1. Experiential Method Experiential Method

2.2. Scientific Method Scientific Method

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Methodology Methodology

Page 5: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

Originates from people’s experience and Originates from people’s experience and intuition without any logical or scientific intuition without any logical or scientific principlesprinciples

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Methodology Methodology Experiential MethodExperiential Method

Page 6: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1. Utility 1. Utility

2. Simple 2. Simple

3. 3. Trial Trial

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Experiential Method Experiential Method --TraitsTraits

Page 7: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1.1. A method but not the perfect oneA method but not the perfect one

2.2. Less cost but high efficientLess cost but high efficient

3.3. Without extension Without extension

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Experiential MethodExperiential Method - -EvaluationEvaluation

Page 8: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

A process by which scientists, collectivelA process by which scientists, collectively and over-time, endeavor to construct ay and over-time, endeavor to construct an accurate representation of the worldn accurate representation of the world

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Scientific Method Scientific Method

Page 9: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1. Observation and description

2. Formulation of a hypothesis

3. Use of the hypothesis

4. Performance of experimental tests

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Scientific Method-Scientific Method-Four StepsFour Steps

Page 10: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1. A hypothesis is a limited statement regarding cause and effect in specific situations

2. A model is reserved when hypothesis has is valid

3. A scientific theory or law represents a hypothesis confirmed through repeated experimental tests

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Scientific Method:Scientific Method:Hypotheses, Models, Theories and Laws Hypotheses, Models, Theories and Laws

Page 11: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

Step1. State the problem

Step 2. Research the problem

Step 3. Form a hypothesis

Step 4 . Test the hypothesis

Step 5. Draw conclusions from the data

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Scientific Method:Scientific Method:Solving Problems with Scientific Methods Solving Problems with Scientific Methods

Page 12: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

A process of creating a mathematical representation of some phenomenon in order to gain a better understanding of that phenomenon

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Mathematical Models Mathematical Models

Four procedures as follows

Page 13: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1. Building a Mathematical Model

2. Verifying and Refining a Model

3. Variables and Parameters

4. Continuous /Discrete in Time

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Mathematical Models Mathematical Models

Page 14: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1. Newtonian Dynamics

2. LaGrangian and Hamiltonian Dynamics

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Mechanical Models Mechanical Models

Page 15: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1. A body remains at rest or in a uniform state of motion if no external force acts on it.

2. A body, upon which a force acts, moves in such a way that the time rate of change of the momentum equals the force.

3. If two bodies act on one another by means of forces, these force

s have equal magnitudes and opposite directions.

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Mechanical Models :Mechanical Models :Newtonian Dynamics

Page 16: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

The actual path of a dynamical system in configuration space extermeizes the action between two defined locations and times

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Mechanical Models :Mechanical Models :LaGrangian and Hamiltonian Dynamics

Page 17: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

Chapter 1: Scientific methodsChapter 2 and 3: Vector and tensorChapter 4: Differential form Chapter5: Variational calculusChapter 6: Lie groupChapter 7: Manifold theoryChapter 8: Classical mechanics Chapter 9 :Finite deformation

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Contents in this course Contents in this course

Page 18: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

Course procedure:20%

Homework & Discussion:20%

Final Exam:60%

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

About ExaminationAbout Examination

Page 19: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

Chapter 1 is over!

Take a rest!

To be continued……

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

11:00am.,Oct.,26,200511:00am.,Oct.,26,2005

Page 20: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1. Identify the problem

2. Begin with a simple model.

3. Identify important variables and constants.

4. Develop the equation(s)

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Mathematical Models:Mathematical Models:Building a Mathematical Model Building a Mathematical Model

Page 21: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1. Is the information produced reasonable?

2. Are the assumptions made?

3. Are there any factors not considered?

4. How do the results, if available?

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Mathematical Models:Mathematical Models:Verifying and Refining a Model Verifying and Refining a Model

Page 22: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1. Output variables

2. Input variables

3. Parameters (constants)

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Mathematical Models:Mathematical Models:Variables and Parameters Variables and Parameters

Page 23: Dr. Wang Xingbo Email: xbwang.nudt@gmail QQ:168731668 Homepage: wxbstudio.home4u.china

1. Is the information produced reasonable?

2. Are the assumptions made?

3. Are there any factors not considered?

4. How do the results, if available?

Mathematical & MechanicalMathematical & MechanicalMethod in Mechanical EngineeringMethod in Mechanical Engineering

Mathematical Models:Mathematical Models:Continuous /Discrete in Time