MT-1620 al.2002 This further implies from above (since No in-plane variation du but this is not exactly true INCONSISTENCY Why? This is an idealized model and thus an approximation. There are, in actuality, triaxial (o,,etc. ) stresses that we ignore here as being small relative to the in-plane stresses we will return to try to define“sma∥) Final note: for an orthotropic material, write the tensorial stress-strain equation as x 2-D plane stress (a,β,,Y=12) Paul A Lagace @2001 Unit⇒ MIT - 16.20 Fall, 2002 This further implies from above ∂ (since = 0) ∂y3 No in-plane variation ∂u3 = 0 ∂yα but this is not exactly true ⇒ INCONSISTENCY Why? This is an idealized model and thus an approximation. There are, in actuality, triaxial (σzz, etc.) stresses that we ignore here as being small relative to the in-plane stresses! (we will return to try to define “small”) Final note: for an orthotropic material, write the tensorial stress-strain equation as: 2-D plane stress σαβ = εσγ (, α β, σ, γ = 1 2 , ) αβσγ ∗ E Paul A. Lagace © 2001 Unit 6 - p. 8