Question

2. Given that a quality-control inspection can ensure that a structural ceramic part will have no flaws greater than 100 µm (10010-6 m)in size, calculate the maximum service stress available with SiC (KIC = 3 MPa m1/2) and partially stabilized zirconia (PSZ) (KIC = 9 MPa m1/2). (See Example 8.3)

Answer 1

SiC=169.26 Mpa

Partially stabilized zirconia=507.77 Mpa

Step-by-step explanation:

SiC

Stress intensity, K is given by

`K=\sigma Y√(\pi a)` hence making
`\sigma` the subject where
`\sigma` is applied stress, Y is shape factor, a is crack length

`\sigma=\frac {K}{Y√(\pi a)}` substituting the given figures and assuming shape factor, Y of 1

`\sigma=\frac {3}{1\sqrt{\pi 100*10^(-6)}}= 169.2569\approx 169.26 Mpa`

Stabilized zirconia

Stress intensity, K is given by

`K=\sigma Y√(\pi a)` hence making
`\sigma` the subject where
`\sigma` is applied stress, Y is shape factor, a is crack length

`\sigma=\frac {K}{Y√(\pi a)}` substituting the given figures and assuming shape factor, Y of 1

`\sigma=\frac {9}{1\sqrt{\pi 100*10^(-6)}}= 507.7706\approx 507.77 Mpa`