Review -- Week 2

Materials and Processes

 Material Properties

    Yield Strength--Strength of a material at its elastic limit

    Ultimate Tensile Strength--the strength of a material right before fracture

    Shear Strength--for ductile materials Ssy = .577Sy; brittle materials, f(Suc,Sut, eef

    Ductility - Elongation >= 5%

    Brittleness

        Uneven Materials - Suc and Sut are not close in value

        Even Materials - Suc and Sut are relatively close in value

    Toughness--Area under s-e curve up to elastic strain

    Hardness - A material's ability to resist deformation due to impact (Charpy test)

    Fracture Toughness --A material's ability to withstand fracture at the root of cracks

    Heat Treatments

        Quenching

        Tempering

        Annealing

    Cold Working

        Strain Hardening

    Case Hardening

        Carbeurizing


Optimization

Single Variable Optimization--No Constraints

   First derivative 0

   Second derivative +(minimum), -(maximum), 0 (saddle point)

Single Variable Optimization - Constraints

Multivariable Optimization - No constraints

    Gradient must be 0

    Hessian must be + definite for a minimum

    Hessian must be - definite for a maximum

Multivariable Optimization - Constraints

    Gradient of Lagrangian must be 0

    Characteristic polynomial roots tell whether we have minimum, maximum, or saddle point


Solver

Need design variable(s) defined

Need constraints defined

Need objective function defined