1. Introduction to Design 2. Materials and Processes 3. Load Determination 4. Stress, Strain, and Deflection 5. Static Failure Theories 6. Fatigue Failure Theories 7. Shaft and Shaft Components

Design -- (Dictionary) (1) create and work out the details of..... (2) make a pattern or sketch of A process which integrates many diverse technical and nontechnical activities to proceed from product definitions, through conceptualization, to production and ultimately disposal.  A design is some type of information  During design is a process  Design science will be a science of process

Need Formulation of specification Creative synthesis DraftingAnalysis Manufacture Testing Redesign as required

the Need  Conceptual Design (concept exploration)  Preliminary Design (demonstration and validation)  Detail Design  Engineering and Manufacturing Development  Production  Operation

During the process of this process, it needs: *Team Work *Communication *Concurrent Engineer (knowledge needed) *Information Management Design is a process.

CAD (Computer-Aided Design) packages: -- Pro/Engineer -- Unigraphics -- Catia -- AutoCAD -- Microstation -- Aries ConceptStation -- IDEAS -- Cadkey -- Solidworks -- DesignCAD

-- ADAMS (Automatic Dynamic Analysis of Multi- bodies Systems) -- Pro/Mechanica (Motion, Structure, Thermal) -- Working Model (2D & 3D)

-- Ansys -- Abcus -- Nastran -- Pro/Mechanica -- Algor

-- TKSolver -- MathCad -- Matlab -- Maple -- Excel -- Lotus

Why do we need the design factor of safety?  because of loading variation;  value from experiment (Lab.) may differ from reality;  reduce probability of failure;  might have some defect in the material property;  cost.

ndnd (When stress is linearly proportional to load) "Strength" represents various quantity chosen by the design. e.g. minimum, mean, yield, tensile, shear, fatigue, etc. and have the same unit as stress. Comparing stress & strength must be of the same reference point.

Taking into account the uncertainty, we have n d = n s n L where n d = design factor of safety, n s = accounting uncertainty of strength, n L = accounting the uncertainty of the load. (if uncertainty of strength is ±15%, the n s = 1/0.85. If the uncertainty of allowable load is ±20%, n L = 1.2. Then, n d = 1/0.85 * 1.2 = )

When the stress is not linearly proportional to the load,

-- ratio of the strength to the actual or computed stress. where σ & τ are the stresses computed using the final selected size.

Design factor of safety, n d -- represents the aim during the beginning or the design. Realized factor of safety, n r -- represents what has actually been obtained from the design.

e.g. 6 parts failed per 1000 parts tested  R = 1- 6/1000 = 0.994

Limits: Max. and Min. Dimensions Tolerance: Difference between the two limits Bilateral Tolerance: Unilateral Tolerance: