ASTM D is a test method used to study the compressive properties of a composite laminate that has a hole cut into it. The GD fixture meets the requirements of ASTM D for open-hole compressive strength testing of fiber-reinforced polymer-matrix composite. The ASTM D / DM fixture is used to perform open-hole compressive tests on multi-directional polymer matrix composite laminates reinforced with high .
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A number in parentheses indicates the year of last reapproval.
A superscript epsilon e indicates an editorial change since xstm last revision or reapproval. The composite material forms are limited to continuous-?
The range of acceptable test laminates and thicknesses are described in 8. 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 astk. Combining values from the two systems may result in nonconformance with the standard. 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.
Current edition approved Mar. Originally approved in Terminology D de?
Terminology E 6 de? Terminology E and Practice E de? In the event of a con? Use of these symbols is restricted to analytical dimensions when used d648 square brackets, as the symbols may have other de? Tolerances may be applied to a nominal value to de?
Anisotropic materials do not have a principal material coordinate system due to the total lack of symmetry, while, for isotropic materials, any coordinate system is a principal material coordinate system. In laminated composites, the principal material coordinate system has meaning only with respect to an individual orthotropic lamina. One of the reference coordinate system axes normally the Cartesian x-axis is designated the reference axis, assigned a position, and the ply principal axis of each ply in the laminate is referenced relative to the reference axis to de?
Summary of Test Method 4. Edgemounted extensometer displacement transducers are optional. Ultimate strength r6484 calculated based on the gross crosssectional area, disregarding the presence of the hole. While the hole causes a stress concentration and reduced net section, it is common aerospace practice to develop notched design allowable strengths based on gross section stress to account for various stress concentrations fastener holes, free edges,?
Two acceptable test procedures are provided. The force is transmitted by shear into the support?
ASTM D Open-Hole Compression (OHC) Testing of CFRP Video | LabTube
The portion of the force initially transferred into the support? Properties that may be derived from this test method include open-hole notched compressive strength OHC. However, since the notch dominates the strength, consistent preparation of the hole, without damage to the laminate, is important to meaningful results. Damage caused by hole preparation will affect strength results.
Some types of damage, such as longitudinal splitting and delamination, can blunt the stress concentration caused by the hole, increasing the force-carrying capacity of the coupon and the calculated strength. Results may also be affected by the ratio of hole diameter to thickness; the preferred ratio is the range from 1. Results may also be affected by the ratio of ungripped specimen length to specimen width; this ratio should be maintained at 2.
Sources of variation in this lateral pressure include? This may result in non-conservative data. Valid OHC strength results should only be reported when appropriate failure modes are observed, in accordance with Thus, data gathered using this test method may not translate directly into equivalent thickstructure properties. Hydraulic grip-loaded data typically exhibit linear behavior at the onset of loading. At high force levels, some nonlinear behavior may be observed due to grip slippage.
For typical specimen geometries, an instrument with an accuracy of 3? Additionally, a micrometer or gage capable of determining the hole diameter to ? If this gap does not meet the minimum requirement, shim the contact area between the support plate and the short grip with stainless steel shim stock. If the gap is too large, shim between the support plate and the long grip, holding the shim stock on the support plate with tape. The threading of the support plate is optional. Standard test specimens are 36 by mm [1.
In Procedure A, the? In Procedure B, the? A cutout exists on both faces of the? The long and short? An optional threaded support plate is shown in Figs. The following general notes apply to these? For non-ambient environmental conditions, the recommended?
However, they can be bene? NOTE 2—Experience has shown that? A short loading train, and either rigidly mounted hydraulic grips or? Hydraulic wedge grips shall apply sufficient lateral pressure to prevent slippage between the grip face and the support? The platen surfaces shall be parallel within 0. If the platens are not sufficiently hardened, or simply to protect the platen surfaces, a hardened plate with parallel surfaces can be inserted between each end of the?
ASTM D6484 Open-Hole Compression (OHC) Testing of CFRP
A rectangle should be 4 FIG. The velocity of the movable head shall be capable of being regulated in accordance with This device shall be essentially free from inertia lag at the speci? Extensometers shall satisfy, at a minimum, Practice E 83, Class B-1 requirements for the strain range of interest, and shall be calibrated over that range in accordance with Practice E The extensometers shall be essentially free of inertia lag at the speci?
Chamber conditions shall be monitored either on an s6484 continuous basis or on a manual basis at regular intervals. This chamber shall be capable of maintaining the gage section of the test specimen at the required test environment during the mechanical test. Sampling and Test Specimens 8. Report the method of sampling. Flag symbol 1 For existing?
Fabric laminates 6 containing satin-type weaves shall have symmetric warp surfaces, unless otherwise speci? This laminate design has been found to yield the highest likelihood of acceptable failure modes.
The panel must be? Report the panel fabrication method. Take precautions when cutting specimens from plates to avoid notches, undercuts, rough or uneven surfaces, or delaminations due to inappropriate machining methods. The use of diamond tooling has been found to be extremely effective for many material systems.
Holes should be drilled undersized and reamed to? Take special care to ensure that creation of the specimen hole does not delaminate or otherwise damage the material surrounding the hole. Ma8 chining tolerances and surface?
Record and report the specimen cutting and hole preparation methods.
Threaded support plate used with bolt-only installation. Estimate the coupon strength to aid in transducer selection, calibration of equipment, and determination of equipment settings. Volume percent of the constituents may be evaluated by one of the matrix digestion procedures of Test Method Dor, for certain reinforcement materials such as glass and ceramics, by the matrix burn-off technique in accordance with Test Method D The void content equations of Test Method D are applicable to both Test Method D and the matrix digestion procedures.
Store the specimens in the conditioned environment until test time, if the test environment is different than the conditioning environment. Measure the hole diameter, Asm, distance from hole edge to closest coupon side, f, and axtm from the hole edge to coupon end, g. Record the dimensions to three signi? If the ultimate strength of the material cannot be reasonably estimated, initial trials should be conducted using standard speeds until the ultimate strength of the material and the compliance of the system are known, and speed of testing can be adjusted.
ASTM D6484 Testing Fixture
However, cases such as elevated temperature testing of a moist specimen place unrealistic requirements on the capabilities of common testing machine environmental chambers.
In such cases, the mechanical test environment may need to be modi?
This should result in the specimen hole being centered in the? Tighten the four bolts just enough to hold the specimen in place during? The ends of asfm grip-jaws on wedge-type grips should be even with each other following insertion to 11 avoid inducing a bending moment which could result in premature failure of the specimen. A gap outside of this tolerance range is indicative of either improper assembly, an out-of-tolerance specimen, or damaged?
Unless coupon rupture is speci? The torque level may be increased above this level when acceptable failure modes cannot be achieved using 7 N-m [60 in-lbf] applied torque. Reduce the compressive force to 7 N [30 lbf], and re-zero and balance all instrumentation. If the specimen is to be failed, record the maximum force, the failure force, and the head displacement at, or as near as possible to, the moment of rupture. NOTE 5—Other valuable data that can be useful in understanding axtm anomalies and gripping or specimen slipping problems includes force versus strain data, percent edgewise bending, and force versus time data.
Retests shall be performed for any specimen on which values are not calculated. Factors considered should include the? The failure is often heavily in?