ASTM D5961/D5961M-96
(Test Method)Standard Test Method for Bearing Response of Polymer Matrix Composite Laminates
Standard Test Method for Bearing Response of Polymer Matrix Composite Laminates
SCOPE
1.1 This test method determines the bearing response of multi-directional polymer matrix composite laminates reinforced by high-modulus fibers by either double-shear (Procedure A) or single-shear (Procedure B) tensile loading of a specimen. Standard specimen configurations using fixed values of test parameters are described for each procedure. However, when fully documented in the test report, a number of test parameters may be optionally varied. The composite material forms are limited to continuous-fiber or discontinuous-fiber (tape or fabric, or both) reinforced composites for which the laminate is balanced and symmetric with respect to the test direction. The range of acceptable test laminates and thicknesses are described in 8.2.1.
1.2 This test method is consistent with the recommendations of MIL-HDBK-17, which describes the desirable attributes of a bearing response test method.
1.3 The multi-fastener test configurations described in this test method are similar to those used by industry to investigate the bypass portion of the bearing bypass interaction response for bolted joints, where the specimen may produce either a bearing failure mode or a bypass failure mode. While this test method may be referenced as guidance in bearing bypass test programs, the scope of this test method is limited to bearing failure modes.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 5961/D 5961M – 96
Standard Test Method for
Bearing Response of Polymer Matrix Composite Laminates
This standard is issued under the fixed designation D 5961/D 5961M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Composites by Matrix Digestion
D 3878 Terminology of High-Modulus Reinforcing Fibers
1.1 This test method determines the bearing response of
and Their Composites
polymer matrix composite laminates by either double shear
D 5229/D 5229M Test Method for Moisture Absorption
(Procedure A) or single shear (Procedure B) tensile loading of
Properties and Equilibrium Conditioning of Polymer Ma-
a coupon. Standard specimen configurations using fixed values
trix Composite Materials
of test parameters are described for each procedure. However,
D 5687/D 5687M Guide for Preparation of Flat Composite
when fully documented in the test report, a number of test
Panels with Processing Guidelines for Specimen Prepara-
parameters may be optionally varied. The material form is
tion
limited to high-modulus continuous-fiber or discontinuous-
E 4 Practices for Force Verification of Testing Machines
fiber reinforced composites for which the elastic properties are
E 6 Terminology Relating to Methods of Mechanical Test-
balanced and symmetric with respect to the test direction.
ing
1.2 This test method is consistent with the recommendations
E 83 Practice for Verification and Classification of Exten-
of MIL-HDBK-17, which describes the desirable attributes of
someters
a bearing response test method.
E 122 Practice for Choice of Sample Size to Estimate a
1.3 This standard does not purport to address all of the
Measure of Quality for a Lot or Process
safety concerns, if any, associated with its use. It is the
E 177 Practice for Use of the Terms Precision and Bias in
responsibility of the user of this standard to establish appro-
ASTM Test Methods
priate safety and health practices and determine the applica-
E 238 Test Method for Pin-Type Bearing Test of Metallic
bility of regulatory limitations prior to use.
Materials
1.4 The values stated in either SI units or inch-pound units
E 456 Terminology Relating to Quality and Statistics
are to be regarded separately as standard. Within the text the
E 1309 Guide for the Identification of Composite Materials
inch-pound units are shown in brackets. The values stated in
in Computerized Material Property Databases
each system are not exact equivalents; therefore, each system
E 1434 Guide for Development of Standard Data Records
must be used independently of the other. Combining values
for Computerization of Mechanical Test Data for High-
from the two systems may result in nonconformance with the
Modulus Fiber-Reinforced Composite Materials
standard.
E 1471 Guide for the Identification of Fibers, Fillers, and
2. Referenced Documents Core Materials in Computerized Material Property Data-
bases
2.1 ASTM Standards:
2.2 Other Document:
D 792 Test Methods for Density and Specific Gravity (Rela-
MIL-HDBK-17, Polymer Matrix Composites, Vol 1, Sec-
tive Density) of Plastics by Displacement
tion 7
D 883 Terminology Relating to Plastics
D 953 Test Method for Bearing Strength of Plastics
3. Terminology
D 2584 Test Method for Ignition Loss of Cured Reinforced
3.1 Definitions—Terminology D 3878 defines terms relating
Resins
to high-modulus fibers and their composites. Terminology
D 2734 Test Methods for Void Content of Reinforced Plas-
D 883 defines terms relating to plastics. Terminology E 6
tics
defines terms relating to mechanical testing. Terminology
D 3171 Test Method for Fiber Content of Resin-Matrix
E 456 and Practice E 177 define terms relating to statistics. In
the event of a conflict between terms, Terminology D 3878
This test method is under the jurisdiction of ASTM Committee D-30 on High
Modulus Fibers and Their Composites and is the direct responsibility of Subcom- Annual Book of ASTM Standards, Vol 15.03.
mittee D30.05 on Structural Test Methods. Annual Book of ASTM Standards, Vol 03.01.
Current edition approved May 10, 1996. Published July 1996. Annual Book of ASTM Standards, Vol 14.02.
2 7
Annual Book of ASTM Standards, Vol 08.01. Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Annual Book of ASTM Standards, Vol 08.02. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 5961/D 5961M
shall have precedence over the other documents. shear modulus that is dependent upon Young’s modulus and
3.2 Definitions of Terms Specific to This Standard: Poisson’s ratio). An orthotropic material has 9 independent
elastic constants. The general concept of orthotropy also
NOTE 1—If the term represents a physical quantity, its analytical
applies to material properties other than elastic, such as
dimensions are stated immediately following the term (or letter symbol) in
thermal, electromagnetic, or optical, although the number of
fundamental dimension form, using the following ASTM standard sym-
bology for fundamental dimensions, shown within square brackets: [M] independent constants and the type of mathematical transfor-
for mass, [L] for length, [T] for time, [Q] for thermodynamic temperature,
mation may differ, depending upon the order of the tensor of
and [nd] for nondimensional quantities. Use of these symbols is restricted
the property. The behavior of an orthotropic material as viewed
to analytical dimensions when used with square brackets, as the symbols
from the principal material coordinate system is called spe-
may have other definitions when used without the brackets.
cially orthotropic. However, if the material behavior is evalu-
3.2.1 bearing area, [L ],n—the area of that portion of a
ated from another coordinate system coupling terms may
bearing coupon used to normalize applied loading into an
appear in the stress/strain relation. While the material itself
effective bearing stress; equal to the diameter of the loaded
remains specially orthotropic, from this other coordinate sys-
hole multiplied by the thickness of the coupon.
tem the material behavior is then called generally orthotropic.
−2
3.2.2 bearing load, P [MLT ],n—the total load carried by
3.2.11 pitch distance ratio, w/D [nd],n—in a bearing
a bearing coupon.
coupon, the ratio of specimen width to hole diameter.
br
3.2.3 bearing strain, e [nd],n—the normalized hole de-
3.2.11.1 Discussion—The pitch distance ratio may be either
formation in a bearing coupon, equal to the deformation of the
a nominal value determined from nominal dimensions or an
bearing hole in the direction of the bearing load, divided by the
actual value, determined as the ratio of the actual distance
diameter of the hole.
br −1 −2 between the center of the hole and the nearest side-edge to the
3.2.4 bearing strength, F [ML T ],n—the value of
x
actual hole diameter.
bearing stress occurring at a significant event on the bearing
3.2.12 ply orientation, u,n—the angle between the refer-
stress/bearing strain curve.
ence axis and the ply principal axis, expressed in degrees, with
3.2.4.1 Discussion—Two types of bearing strengths are
a range of − 90° < u # 90°. The ply orientation is expressed as
commonly identified, and noted by an additional superscript:
a positive quantity when taken from the reference direction to
offset strength and ultimate strength.
br −1 −2
the ply principal axis, following a right-handed Cartesian
3.2.5 bearing stress, s [ML T ],n—the bearing load
coordinate system.
divided by the bearing area.
3.2.6 diameter to thickness ratio, D/h [nd],n—in a bearing
3.2.12.1 Discussion—The reference direction is usually re-
coupon, the ratio of the hole diameter to the coupon thickness.
lated to a direction of load application or a major geometric
3.2.6.1 Discussion—The diameter to thickness ratio may be
feature of a component.
either a nominal value determined from nominal dimensions or
3.2.13 ply principal axis, n—the coordinate axis in the plane
an actual value determined from measured dimensions.
of a lamina that is used as the reference direction for that
3.2.7 edge distance ratio, e/D [nd],n—in a bearing coupon,
lamina.
the ratio of the distance between the center of the hole and the
3.2.13.1 Discussion—The ply principal axis will, in general,
coupon end to the hole diameter.
be different for each ply of a laminate. The angle made by this
3.2.7.1 Discussion—The edge distance ratio may be either a
axis relative to the reference axis is the ply orientation. The
nominal value determined from nominal dimensions or an
convention is to align the ply principal axis with a material
actual value determined from measured dimensions.
feature that is the direction of maximum stiffness (such as the
3.2.8 nominal value, n—a value, existing in name only,
fiber direction for unidirectional tape or the warp direction for
assigned to a measurable quantity for the purpose of conve-
fabric-reinforced material). Conventions for other laminated
nient designation. Tolerances may be applied to a nominal
material forms have not yet been established.
value to define an acceptable range for the quantity.
bro −1 −2
3.2.14 principal material coordinate system, n—a coordi-
3.2.9 offset bearing strength, F [ML T ],n—the value
x
nate system with axes that are normal to the planes of
of bearing stress, in the direction specified by the subscript, at
symmetry inherent to a material.
the point where a bearing chord stiffness line, offset along the
bearing strain axis by a specified bearing strain value, inter- 3.2.14.1 Discussion—Common usage, at least for Cartesian
axes (123, xyz, etc.), generally assigns the coordinate system
sects the bearing stress/bearing strain curve.
3.2.9.1 Discussion—Unless otherwise specified, an offset axes to the normal directions of planes of symmetry in order
that the highest property value in a normal direction (for elastic
bearing strain of 2 % is to be used in this test method.
3.2.10 orthotropic material, n—a material with a property properties, the axis of greatest stiffness would be 1 or x, and the
lowest (if applicable) would be 3 or z). Anisotropic materials
of interest that, at a given point, possesses three mutually
perpendicular planes of symmetry defining the principal mate- do not have a principal material coordinate system due to the
rial coordinate system for that property. total lack of symmetry, while, for isotropic materials, any
3.2.10.1 Discussion—As viewed from the principal material coordinate system is a principal material coordinate system. In
coordinate system of an orthotropic elastic material, exten- laminated composites the principal material coordinate system
sional stresses are totally uncoupled from shear strains and the has meaning only with respect to an individual orthotropic
shear moduli are totally independent of the other elastic lamina. The related term for laminated composites is reference
constants (unlike a metal, which is isotropic and that has a coordinate system.
D 5961/D 5961M
3.2.15 quasi-isotropic laminate, n—a balanced and sym- 3.3.13 K—calculation factor used in bearing equations to
metric laminate for which a constitutive property of interest, at distinguish single-shear tests from double-shear tests in a
a given point, displays isotropic behavior in the plane of the
single bearing strain equation.
laminate. Common quasi-isotropic laminates are [0/660]s and
3.3.14 L —extensometer gage length.
g
[0/645/90]s.
3.3.15 n—number of coupons per sample population.
3.2.15.1 Discussion—Usually a quasi-isotropic laminate re-
3.3.16 P—load carried by test coupon.
fers to elastic properties, for which case, the laminate contains
f
3.3.17 P —load carried by test coupon at failure.
equal numbers of identical plies at k orientations such that the
max
3.3.18 P —maximum load carried by test coupon prior to
angles between the plies are 180i/k,(i 50, 1,., k − 1); k $
3. Other material properties may follow different rules. For failure.
example, thermal conductivity becomes quasi-isotropic for k $
3.3.19 s —standard deviation statistic of a sample popu-
n−1
2, while strength properties generally are not capable of true
lation for a given property.
quasi-isotropy, only approximating this behavior.
3.3.20 w—coupon width.
3.2.16 reference coordinate system, n—a coordinate system
3.3.21 x —test result for an individual coupon from the
i
for laminated composites used to define ply orientations. One
sample population for a given property.
of the reference coordinate system axes (normally the Carte-
3.3.22 x¯—mean or average (estimate of mean) of a sample
sian x-axis) is designated the reference axis, assigned a
population for a given property.
position, and the ply principal axis of each ply in the laminate
3.3.23 d—extensional displacement.
is referenced relative to the reference axis to define the ply
orientation for that ply.
3.3.24 e—general symbol for strain, whether normal strain
3.2.17 specially orthotropic, adj—a description of an ortho-
or shear strain.
br
tropic material as viewed in its principal material coordinate
3.3.25 e —bearing strain.
system. In laminated composites a specially orthotropic lami-
br
3.3.26 s —bearing stress.
nate is a balanced and symmetric laminate of the [0:i/90:j]ns
family as viewed from the reference coordinate system, such
4. Summary of Test Method
that the membrane-bending coupling terms of the stress/strain
relation are zero. 4.1 Procedure A, Double Shear:
3.2.18 tracer yarn, n—a small filament-count tow of a fiber
4.1.1 A flat, constant rectangular cross-section coupon with
type that has a color that contrasts with the surrounding
a centerline hole located near the end of the coupon, as shown
material form, used for directional identification in composite
in the coupon drawings of Figs. 1 and 2, is loaded at the hole
material fabrication.
in bearing. The bearing load is normally applied through a
3.2.18.1 Discussion—Aramid tracer yarns are commonly
close-tolerance, lightly torqued fastener (or pin) that is reacted
used in carbon fiber composites and carbon tracer yarns are
in double shear by a fixture similar to that shown in Figs. 3 and
commonly used in aramid or glass fiber composites.
4. The bearing load is created by pulling the assembly in
bru −1 −2
3.2.19 ultimate bearing strength, F [ML T ],n—the
x tension in a testing machine.
value of bearing stress, in the direction specified by the
4.1.2 Both
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.