Lecture21-Notes - ME 382 Lecture 21 YIELD OR FRACTURE? Can...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
ME 382 Lecture 21 1 Y IELD OR F RACTURE ? Can design by comparing fracture load to load required for either (i) Onset of yield ( ˜ σ H = Y anywhere on section) (ii) Net section yield or "plastic collapse" ( ˜ H = Y across section) - upper bound on failure load The two are equivalent for uniaxial tension Yield only occurs along planes of maximum shear Load for onset of yield ( P e ) = load for net section yield ( P p ): P e =P p = (2 b -2 a ) t σ Y Two possible loads for yield: P e = P p = (2 b - a ) t σ Y P Y = P p = 3 . (2 b - 2 a ) t σ Y (for yield of ligament) (inverse of hardness test - complex stress between cracks) Ligament yields only if a > 4 b / 5 Onset of yield and net section yield are different in bending Moment for onset of yield (rectangular beam): M e = tb 2 Y /6 Moment for net section yield (rectangular beam): M p = tb 2 Y /4
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ME 382 Lecture 21 2 Net section yield of beam of width b & crack of length a : M p = t b a ( ) 2 σ Y /4 Complication of beam with single crack and axial load . ..... Moment at cracked section: M = Pa /2 Maximum nominal stress on cracked section (ignoring stress singularity): = M b a ( ) 2 12
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 5

Lecture21-Notes - ME 382 Lecture 21 YIELD OR FRACTURE? Can...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online