From my days working aerospace, I have the
following equations that came from a DoD/NASA Adv. Composites Design Guide,
dated July 1983:
For single lap shear joints:
1/K = [ (t1 + t2)^2 ] / (Eb * D^3)
+ 3.72 * [ 1 / (t1*E1) + 1 / (t2*E2) ]
For double lap shear joints:
1/K = [ (t1 + t2/2)^2 ] / (2 * Eb *
D^3) + [ 2 / (t1*E1) + 1 / (t2*E2) ]
Where:
K = lateral stiffness of the
fastener/joint
Eb = modulus of elasticity of the bolt
D = bolt diameter
t1 = thickness of outer plate
E1 = longitudinal modulus of elasticity of the
outer plate
t2 = thickness of inner plate
E2 = longitudinal modulus of elasticity of the
inner plate
For the axial stiffness of a fastener, I usually use K = EA/L
Greg
----- Original Message -----
Sent: Tuesday, November 21, 2000 12:57
PM
Subject: fastener stiffness
representation
Hi!
I was wondering if anyone can give me some
tips or point me to some references
on estimating stiffness coefficients
for springs that represent fasteners in
finite element models. To be
more specific, if there are 3 springs between two
coincident nodes, one for
each translational DOF, how would one go about
estimating the stiffness
coefficients for these springs? Thank you in advance.
M.
Coker