Dakota MAX II, Operation Manual

Page: 118 / 216

Dakota Ultrasonics
110
Area
For bolts with complex geometry, the areas should be estimated by averaging each
individual area and length. In the case of a hollow fastener, the area of the hole must
be subtracted from the overall area. The area of a fastener with complex geometry
can be estimated as follows:



L
AL
A
AVG
Average Area
A = Area of a region
L = Length of a region
The value for the Modulus of Elasticity, or Young’s Modulus, should be provided
directly from the manufacturer of the bolts.
E = Modulus of Elasticity of the Bolt Material From Manufacturer
The effective length is the average length of the fastener under stress when a load is applied.
For an applied constant load, the elongation of a fastener is directly proportional to the
effective length. Therefore, errors in the effective length will result in load errors by a
proportional amount. The effective length of a fastener is a combination of the actual clamp
length of the joint being fastened, plus that area of stress found in the head, nut(s), and or
blind hole of the fastener.
C L A M P L E N G T H
E F F E C T IV E L E N G T H
1 /2 T H E D IA M E T E R 1 /2 T H E D IA M E T E R
CLAM P LEN G TH
EFFECTIV E LEN G TH
1/2 TH E D IAM ETER 1/3 TH E D IAM ETER