# FE Post Processing Plotting Campbell Diagram Goodman Diagram Fracture Yield Principal Stress.

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FE Post Processing Plotting Campbell Diagram Goodman Diagram Fracture Yield Principal Stress

POST PROCESSING PLOTS

Deformed Shape Plot

Contour Plots

History Plot

Invert Colors for Hard Copies

CAMPBELL DIAGRAMS

Campbell Diagram

Probabilistic Campbell Diagram

GOODMAN DIAGRAMS

Inputs Include Material: – Ultimate tensile strength, – Yield stress – 0.2%, – High cycle fatigue strength, Loads – Steady stress, – Vibratory, Half amplitude, zero-peak, Full amplitude, peak-peak,

HCF Test Data Fit R=-1 data – For example: Pick number of cycles to failure: N f Solve for corresponding half-amplitude stress:

Goodman Diagram Material Inputs

My Choice

FRACTURE MECHANICS

Fracture Modes

Stress Intensity Factor Mode I Stresses near crack tip are singular and vary as the inverse square root of distance from crack tip K I is the stress intensity factor

Fracture – ¼ Points

Modeling Cracks

VON MISES STRESS & PLASTIC YIELDING

Von Mises Stress is the stress tensor is the equivalent hydrostatic pressure is the deviatoric stress

Invariants of Stress Invariants do not change values when coordinate system is rotated. The first invariant of the stress is The second invariant of the deviatoric stress is The third invariant of the deviatoric stress is the determinant.

Uniaxial Tension :yield stress

Equivalent Mises Stress Yielding occurs when Or when equivalent stress When yielding occurs Stress ratio is

PRINCIPAL STRESSES

Principal Stresses Eigenvalues of stress tensor (matrix) are principal stresses – All values are real – Order is 1:maximum, 2: intermediate, 3:minimum Associated eigenvectors are normal to face Use maximum principal stress for fracture 11 22 33 x y z

STRESS CONTOURS

Ansys Stress Contour Plots

FE Post Processing Plotting – Includes displaced, contour, and scatter plots Campbell Diagram – Finds important resonances Goodman Diagram – Predicts high cycle fatigue life Fracture – Indicates failure due to crack propagation Yield – Establishes yield through the use of equivalent (Mises) stress Principal Stress – Aids in determining failure due to presence of flaws

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