Gardner Impact ASTM D, D Falling Dart Impact (Gardner Impact) ASTM D, ASTM D Scope: Falling dart impact, also known as Gardner. This standard is issued under the fixed designation D ; the number 1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics. ASTM D Standard Test Method for Impact Resistance of Flat, Rigid Plastic Specimen by Means of a Striker Impacted by a Falling Weight (Gardner Impact).

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A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. The values given in brackets are for information only.

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. For example, in some cases incipient cracking in glass-reinforced polymers is difficult to differentiate from the reinforcing? In such cases, apply a penetrating dye such as gentian violet to the stressed surface to determine the onset of crack formation.

Current edition approved February 1, Originally approved in Last previous edition approved in as D – Different materials respond differently to changes in the velocity of impact. Consider the end use environment and requirements when choosing from the available striker geometries. However, the selection of any one of the striker geometries is permitted, after such consideration.

NOTE 2—Material processing can have a signi? Consult relevant material standards for processing guidelines FIG. Summary of Test Method 4.

There is no satm means for correlating the results of tests made by different methods or procedures. However, the velocity of a free-falling object is a function of the square root of the drop height. A change of a factor of two in the drop height will cause a change of only 1.

Hagan, et al 2 found that the mean-failure energy 6.

Thus, use impact tests only to obtain relative rankings of materials. Impact values cannot be considered absolute unless the geometry of the test equipment and specimen conform to the v5420 requirement.

Data obtained with different geometries, cannot, in general, be compared directly with each other. Therefore, factors including surface features? This test can be carried out at any reasonable temperature and humidity, thus representing actualuse environments. However, this test method is intended primarily for rating materials under speci?

Adapt the apparatus from Test Method D for use in this test method or obtain the apparatus commercially. Ast, apparatus shall consist of the following: Use a bracket to hold the d542 in a vertical position by attaching it to the base and also to hold the hand knob, which is a pivot arm alignment for the striker, about 50 mm [2 in.


Round the top edge of the opening in each specimen-support plate to a 1. A suggested design is given in Fig. This geometry can be achieved by removing the removable support ring on the standard Gardner instrument. The main body of the block or base shall have maximum dimensions of 16 by 30 by 30 in. Place this block or base at a height suitable for ease of operation.

It is not necessary to bolt blocks or bases of this weight to the? Alternatively, affix testers directly to the? Use of rubber mats either directly under the tester or supporting apparatus is prohibited.

For each different material tested, make com- FIG. If mean failure energy differences between two types of supports are found to be statistically nonsigni? NOTE 3—Such block dimensions conform to commercially available butcher block tables.

Use a random numbers d54420 if desired. Ensure that the same surface or area, or both, is targeted on all test specimens. NOTE 5—Normally the specimen is not clamped because the test apparatus does not have provision for clamping.

Gardner Impact ASTM D4226, D5420

However, the apparatus can be modi? NOTE 1—Depth of penetration when fully seated shall be See Test Methods D for descriptions of suitable micrometers.

The specimens shall be free of obvious imperfections, unless the imperfections constitute a variable under study. Machining specimens to reduce thickness variation is not permissible. If the approximate mean-failure height is unknown, six or more additional specimens shall be used to d4520 the appropriate starting point of the test.

Production parts shall be tested in the as-received condition to determine conformance to speci? Refer to the appropriate material speci?


NOTE 4—As few as ten specimens often yield sufficiently reliable estimates of the mean-failure height. However, in such cases the estimated standard deviation will be relatively large 1.

Be sure the specimen is? Raise the weight in the tube to the desired impact value, as shown on the appropriate scale, and asym it so that the weight drops on the striker. Permanent deformation alone is not considered failure, but note the extent of such deformation depth, area. For some polymers, for example, glassreinforced polyester, it is difficult to assess incipient cracking with the naked eye.

In such cases, it is permissible to expose the stressed surface to a penetrating dye, such as gentian violet, to help determine the onset of cracking. Then test the second specimen. D — 04 Test each specimen only once. Use one symbol, such as X, to indicate a failure and a different symbol, such as O, to indicate a nonfailure at each height level. A sample computation of sw is found in Appendix X1. D542 positive sign is used when the events are nonfailures. Refer to the example d520 Appendix X1.


MFE 5 hwf 2 ini, where: Report other observed deformation due to impact, whether the specimens fail or not. Precision and Bias 4 Data from only three laboratories were used in calculating the values in these tables. For each material, all samples were prepared at one source, but the individual specimens were prepared at the laboratories that tested them.

Each test result was the mean of multiple individual determinations Bruceton Staircase Procedure 1. Each laboratory obtained two test results for a material.

Warning—The following explanations of r and R Do not apply the data in Table 2 and Table 4 rigorously for acceptance or rejection of a material. Data in these tables are speci? The principles of D 20 — Practice E to generate data speci? PVC 57 lb Base lb Base lb Base Floor Twenty specimens were used for each sample calculation, with a minimum of specimens used for each averaged test result. For the convenience of the user, Committee D20 has highlighted those changes that impact the use of this test method.

This section also includes descriptions of the changes or reasons for the changes, or both. D — D — 98a: ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.

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