Assume that an aneurysm can be modelled as a thin walled sphere having an inner

ID: 1861628 • Letter: A

Question

Assume that an aneurysm can be modelled as a thin walled sphere having an inner radius

of 3 mm, a wall thickness of 20 ?m, with a blood pressure of 130 mm Hg. The critical stress at

which the aneurysm is liley to rupture is on the order of 5 MPa. A) Would you recommend that

the patient undergo risky surgery or would it be safe to closely monitor the aneurysm over time?

B) The capability to accurately measure the wall thickness is a critical factor in predicting the

likelyhood of a rupture. What can you say about the variation in measuring the wall thickness

and it

stress in sphere = pd/4t

since 1mm Hg = 133.32 Pa

130mm = 21331 pa

stree = 21331*3.02*10^-3/ 4*20*10^-6

= 805245 pa

that is less tha 5*10^6 pa

so it will be safe