Chapter 8 – Combined Loading

Chapter 8 – Combined Loading

CL = 2 or more stresses at a given point.

8.1 Thin-Walled (r/t > 10) Pressure Vessels:

Assumption: Thin walled so assume stress uniform throughout the wall!

0)2()(20 1 dyrpdytFx

tpr

1 Normal stress in the hoop direction

1 uniform throughout wall!

Circumferential or Hoop Stress:

Assumption: Thin walled so assume stress uniform throughout the wall!

0)()2(0 22 rptrFy

tpr22 Normal stress in the

longitudinal direction

Longitudinal Stress:

Note, this stress = hoop stress/2

tpr22

tpr

1

Summary: Cylindrical Pressure Vessels:

Circumferential or Hoop Stress

Longitudinal Stress

What about Spherical Pressure Vessels?

tpr221

Examples:

Examples:

Elastomer volume = 13.8 in3

(was 16.2 in3)

Wall thickness = .10”

RJM 6/2/04