Page 340 - Mechanical Behavior of Materials

Section 8.2 Preliminary Discussion 341

Table 8.2 Fracture Toughness of Some Polymers and Ceramics at Room Temperature

Material √ K Ic √ Material √ K Ic √
Polymers 1 MPa m (ksi in) Ceramics 2 MPa m (ksi in)
ABS 3.0 (2.7) Soda-lime glass 0.76 (0.69)
Acrylic 1.8 (1.6) Magnesia, MgO 2.9 (2.6)
Epoxy 0.6 (0.55) Alumina, Al 2 O 3 4.0 (3.6)
PC 2.2 (2.0) Al 2 O 3 , 15% ZrO 2 10 (9.1)
PET 5.0 (4.6) Silicon carbide 3.7 (3.4)
Polyester 0.6 (0.55) SiC
PS 1.15 (1.05) Silicon nitride 5.6 (5.1)
PVC 2.4 (2.2) Si 3 N 4
PVC 3.35 (3.05) Dolomitic limestone 1.30 (1.18)
rubber mod. Westerly granite 0.89 (0.81)
Concrete 1.19 (1.08)

Notes: 1,2 See Tables 4.3 and 3.10, respectively, for additional properties of similar materials.
Sources: Data in [ASM 88] p. 739, [Karfakis 90], [Kelly 86] p. 376, [Shah 95] p. 176, and
[Williams 87] p. 243.

a, inches
0 0.5 1.0 1.5 2.0 2.5
100
S
600
a t b
σ = 518 MPa a 80 S
o
S, Gross Stress, MPa 400 area loss 60 ksi

failure data

t = 1.5 mm
200 b = 152 mm 40
20
K = S πa = 66 MPa m
c
0
0 20 40 60
a, Crack Length, mm
Figure 8.5 Failure data for cracked plates of 2014-T6 Al tested at −195 C. (Data from
◦
[Orange 67].)