Question

Problem: 3.2: [20pts) a) Calculate transition crack lengths at for the following materials: Material Kic/MPa ms 02/MPa F-Steel 187 760 PET 50 59 ABS 3.0 42 Epoxy 0.6 40 b) Comment on the values obtained and any trends observed for the different classes of material. Which particular materials do you think are likely to be internally flawed?

Answer 1

We know that, Toam sitim crack length is given as Ccoit KIC bys HE i) F-steel 0.5 Kico 187 Mpam PaPa 760 MPa 2 Can't x S. Cena 6187 760 Jт 0.0605 T Conit 0:03.4 Im 34.1 mm 2) PET KIC Gys mois MPa mpa 59 Con't a ( त M 0.608

Cont 0.343 m = 343 mm 2 ABS Đc : Gys 3 MPamo.5 42 MPa 2 Ccoitoa (3. 0.00510 vo 20 2877 m Ganita 2.8 77 mm 4) Epoxy kac bys = O a6 MPamoos 40 MPa Conte Coro 20-000225 e 06.00-12.69m = 0.000 1269 m

Can't = o.1269 mm Material ЕРозу ABS F steel PET Cen't (mm) O126 2-877 34:1 343 - So epoxy has minimum transition crack length and PET has maximum tronssition crack length. As ratio of kic to bys decreaser the (σαρο length deco eases. has least ratio and PET has maxionum ratio. the So е ероя