Nov 26, 2017 - NASA. Contractor. Report 4608. Strength. Evaluation of Socket Joints. Larry. C. Rash ...... loads, F 0 and M0, and the load center locations,. 21 and 22 ...... 1150. 1120. PRINT. " 1130. PRINT. " 1140. PRINT. " 1150. PRINT. 1160 ... 1400. PRINT. " X,in. MOMENT,in-lbs. STRESS,psi. MOMENT,in-lbs. STRESS, ...
https://ntrs.nasa.gov/search.jsp?R=19940032751 2017-11-26T13:10:55+00:00Z
NASA
Strength Larry Calspan
National Langley
C.
Evaluation
of Socket
Contractor
Report
4608
Joints
Rash Corporation
° Tullahoma,
Tennessee
Aeronautics and Space Administration Research Center • Hampton, Virginia
Prepared 23681-0001
for Langley Research Center under Contract NAS1-19385
June
1994
STRENGTH
EVALUATION Table
INTRODUCTION
ANALYSIS
Forward Load
Forward
Member
Bending
Aft Bending
Moment
Forward
Joint
Bending
................................................................................
..................................................................................................
..........................................................................................................
Contact
Moment
for Aft Joint
Member
with Continuous
Intermediate
Contact
Relief .....................................................................
Equation
Moment
Equation
Equation
Equations
Shear
Stress
........................................
Stress
5 7
8
9 9
................................................................................................
12
.................................................................................................
13
........................................................................................................
for Aft Joint
Member
with
Internw(tiatc
Contact
Relief .........................
..................................................................................................................
...................................................................................................................
.....................................................................................................................................
Pressure
3 3
Stress .................................................................................................................................
Stress
Contact
with
Relationships
Transverse IIoop
Contact
3
............................................................................................................................
Moment
Moment
Bending
Equation
Equation
Member
Aft Bending
Continuous
Equations
Bending
Stress
with
Moment
Development
Forward
Joint
1
............................................................................................................................
Moment
Bending
Bending
of Contents
..........................................................................................................................................
Development
Central
JOINTS
...............................................................................................................................
Joint
Load
OF SOCKET
...................................................................................................................
14
16
17 17 18 19 19
CONCLUSION
..................................................................................................................................
21
APPENDICES
...................................................................................................................................
23
Appendix
A:
IBM BASIC
A1)pendix
B:
Validation
Appendix
C:
List of Symbols
REFERENCES
Program of Loading
................................................................................................
23
with
28
Finite
Elements
...............................................................
..........................................................................................................
..................................................................................................................................
31 32
Ill
FIGURES
iv
..........................................................................................................................................
33
Figure
1.
Typical
Figure
2.
Figure
Socket
Type
Joints
...........................................................................................
33
Illustration
of Socket
Joint
with
Continuous
34
3.
Illustration
of Socket
Joint
with
Intermediate
Figure
4.
Typical
Figure
5.
Finite
Figure
6.
Load
Socket Element Distributions
Joint
Loadings
Model
and
of Socket
Resulting
Results
Contact Contact
.................................................... Relief ........................................
....................................................................
Joint .............................................................................
from
FEA ........................................................................
35 36 37 38
INTRODUCTION
The
results
included
this
report
is intended
was performed of the the
parallel loads
determining support
systems.
overlapping includes
engages
lamppost
with
is supported
determine support
if the the
be
require
some
by
of a unit
results
joint
and
in this can
joints
and
and
for a joint
between
the joint
a gap
be used during was
joints
was
is applicable members
can
system,
which
and
the
analytical
is sufficient conditions. joint
for
The strength
that
The
determine
to what
the
is included
of new
provide
a method
in wind
tunnel
be
model
applicable
to
are illustrated
in Figure
be considered
to be
basically support
of this
report.
A
herein
can
be used
to
of the
soil
to
included pressure
any 1 and
end of a model
is the subject
of
laterally
round
bar assembly
and
to external
forces
and
can
tongue
and
proper here
the design
of a clamped
are subjected
technique. to
bearing
to
forward
technique the
to
found
found
by an aft support
analytical
are
in the
during
for most
the joint
other
joint
at the
the
groove
stress by
joint
relationships
using
strip
theory
moments
would,
however,
which
could
to evaluate
be the
of the joint.
report
for both
the method
a plane
Transonic
The
development
width
method
over
National
objective type
reacted
about
systems
easily
socket
reacted
define
member.
type
analysis
original
in the joints
to better
support could
were
that
was developed
joint
ground
groove
this
a similar
provided
the
high wind
and
using
be used
from
penetration
during
additional
accomplished
The
of
of a tongue
evaluated
strength
depth
the
that
was
1, and
study
the stresses
moment
tapered,
of the
analysis,
of this
technique
analytical
one
to that
of a validation
in the joint
tool that
for which
the results
see Reference
moment
a design
the
report,
the
in the model
the
is supported by
lamppost
the strength
socket
and
Prior
new analytical
precise,
where
pressure
B.
the result
in concentric,
Some joints
to document
found
more
completed,
contact
and
as a company
by assuming
were
joints
be
configurations
by the
resolved
The
and stresses Once
general
system
To
released
as Appendix
and to provide
type joint.
supported
both
loads
were
sting
systems. the
analysis
here
centerline.
LaRC
support
that
the stresses
in typical
at NASA
model
and
horizontal
stresses
were previously
included
systems
of the joint
and
Facility
and
support
to the
report
to formalize
later
model
center
in this
a joint
the
form
design
applications where
with
members
of new model the
the joint
intermediate along
of equations
need of more members contact
about
that
are for a concentric,
support
systems
lengthy
relief.
one-third
The joint
to determine
analyses
are in continuous
of the midsection
socket
the
can be avoided.
contact with
tapered
along
intermediate of the joint,
the
type
strength
of
Results
are
full length
contact typical
relief of
of has
NASALaRCstingjoints,andthejoint members arein full contactforeandaft of thismidsection gap. Illustrationsof bothjoint typesaregivenin Figures2 and3. Analytically,the approach for bothwas to useStrengthof Materialsprinciplesto analyzethe joint members by idealizingthe joint as two rigid, parallelbeamsthat arejoinedby an infinite numberof springsalongthe contactingsurfaces. The contactloadscanbepicturedasbeingequivalentto theloadsdeveloped in the springsalongthe lengthof thejoint attributedto thedifferentialslopebetween two rigidjoint members.The contact loadsbetweenthe joint members arerepresented as externallyapplied,linearlyvarying,distributed loadsandareasshownon thefreebodydiagrams in Figure2 and3. Eachjoint memberis treatedlike a simplebeamandthe contactloadsbetween the beamsaretakento act likeexternalloadsthat are independently appliedto eachof the two beams.Forthefirst joint member, depictedin Figures2b and3b, theexternallyapplied loadsarebalanced by theapplicationof thecontacttypeloadsandfor the secondjoint member, depictedin Figures2cand3c,thecontactloadsarethe onlyloadsthat act on theendof thecantilevered beams.Thesecontactloads,in conjunction with theexternallyapplied loadsfor the forwardjoint members are usedto developindependent expressions for the bending momentalongthelengthof thejoint for thetwojoint members.Thejoint stressrelationships for the joint membersare determinedfrom the bendingmomentequationsby includingthe effectsof appropriatesectionproperties for a givengeometry.The geometry of the contactingsurfaces for the joint in this reportis in theshapeof a frustumof a coneandis representative of the taperedsocket typejointsfoundin modelsupportsystems in NASALaRCwindtunnels. The resultsin this report joints have
directly been
from
programed
report.
A copy
tapered,
socket
joint
can
be used
dimensions
for a personal
of an IBM BASIC type
joint
is included
to determine and
externally
computer program
the
that
as Appendix
distributed
applied
loads.
to automatically was developed A.
contact
loads
As a design compute
to evaluate
all
and aid,
the
stresses
the key equations
results
the results
in sting
given
in this
for a concentric
ANALYSIS
FORWARD
Load
To
JOINT
WITH
CONTINUOUS
joint,
the
CONTACT
Development
identify
moments
the and
members loads
applied
required
mating
surface
the
that
unique that loads forward
F0
the
similar
for this
joint
+
W 1
linear
load
=
L
the
- b
+
variation
triangles
(the
Wl
(l_a-c)
be used
location,
consider
distributed
linear refer
and
at
and
three
moments
provides to Figure
2b.
that
upper
there
each
end
two
for a third Summing
some surface
variable
of the
joint,
equations
equation.
distributed intermediate to
lower
unknowns
which
concentrated
be required and
vertical
the
other
for a
an assumption
For an illustration
in the
of
to simplify
or the
will therefore
of the
forces
at
mating
in terms
of the
are two other
equations
provide
the basis
the
reverses
bending
axis of the beam
magnitudes
as a dependent
loads
loads,
the longitudinal
loading
from
distributed
can be developed
for maximum
can
distributed
loads along
of the
shift
to evaluate
direction
of the for the
0
about
[
of the
solving
loads
reversal
be used
for distributed
direction
location
can
yields
W 2
moments
+
are
dimensions
member
- W 1
reversal
loads
load variation
and
The
of forces
loads
relevant
pressure
tile contact
to the
Summation
distributed
Summing
M0
load
are equivalent
and
a linear
magnitudes
solution. the
by assuming
where
this
To solve
Expressions
equilibrium.
is literally and
contact
stresses.
contact
achieve
maximum
loads
the
to the
to
which
expressions.
in the
loads
attributed
location
are
stresses
ultimately
the externally
For
MEMBER
load center
w2
c
of the externally
(b c)l E 3
assumption,
ratio
_
(X)
-
W2
the
of all corresponding
L - a
loads
can
applied
M0, provides
:°
-
be
F 0 and
loads,
related
sides of similar
(2)
by using triangles
the
geometric
properties
of
are equal)
(3)
To
equate
the
determined
preceding
in terms
load
for a linearly
load
times
equations,
of concentrated
varying
the distance
for the distributed
in terms
using
load the
that
load
distributed
a basic
loads
definition
that
goes to zero is half the
acts.
The
of the concentrated
following
given
in equation
an equivalent
product
relationships
(3) can
of the peak distributed are rearranged
to solve
loads.
(4)
c
(5)
(4)
concentrated
and
loads
(5)
after
into
equation
(3)
gives
the
following
relationship
between
the
grouping
[(b-a)2 - 2c(b-a) + c2] W2 - c2W1 : 0
Three
linearly
independent
simultaneously and
for the
M0) and
the joint
3(b-a)
[M 0
equations,
three
(1),
unknowns
dimensions
+
be
concentrated
2W 2
equations
equivalent
which
for the
2W 1 b-a-c
-
w2 substituting
loads,
distributed over
loads
Wl
expressions
F0(L-a)]
(2),
(3a)
and
(c, W 1 and
as shown
- 2(b-a)2F
in Figure
(3a)
W2) 2.
are
in terms The
now
available
of the externally
load reversal
location
that
can
be
applied would
solved
loads
(F 0
be
0 (6)
6[M 0
To simplify in terms
the
+
F0(L-a)]
following
of the load
3[M 0
+
F0(L-a)]
location,
0
for the equivalent c, which
is defined
-'-
+
concentrated
loads,
in the preceeding
the equations
are expressed
equation
- cF 0
(7)
2(b-a)
3[M 0 W2
expressions
reversal
W 1
- 3(b-a)F
F0(L-a)][c + 2(b-a)
2(b-a)]
F0
(8)
The
dimension
the
varying
The
identifying contact
dimension
surfaces
the load
load
identifies
to the
lower
acting
Forward
Moment
Bending
Expressions
along
downward
contact
acting
considering
the forward as a function
the beam, using
magnitude load
the external
The
variable
would
location and
following
where
the
distinguishes
and for the upward
development contact
where
acting
be used
loads
separate
loads,
to simplify
expression
as an independent shift
governing
see Figure
the
from
the
variable.
upper
equations
for
mating
are required
2.
moment
Wx
at
w1
of the joint
loads
by
load of the x-distance
similar
figure.
triangles,
general
_L-b
the
x-L+b
distributed
distance
would
"x"
from
be
L-o-c
for L-
concentrated
__
load
b.00001
470 480 490
E=O# F=0# PRINT
500 510
INPUT GOTO
520
PRINT
530 540
INPUT PRINT
550 560
INPUT PRINT
570 580 590
INPUT DI2,DM2,DO2 IF DMI.0001) ABS(LAF-X)