ASTM F320-05
(Test Method)Standard Test Method for Hail Impact Resistance of Aerospace Transparent Enclosures
Standard Test Method for Hail Impact Resistance of Aerospace Transparent Enclosures
SIGNIFICANCE AND USE
This test method may be used to determine the hail impact resistance of windshields for acceptance, design, service, or research purposes. By coupling this method with the installed angle and velocity of a specific aerospace vehicle, design allowables, criteria, and tolerances can be established for that vehicle’windshield.
SCOPE
1.1 This test method covers the determination of the impact resistance of an aerospace transparent enclosure, hereinafter called windshield, during hailstorm conditions using simulated hailstones consisting of ice balls molded under tightly controlled conditions.
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
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. For specific hazard statements see Section .
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F320 – 05
Standard Test Method for
Hail Impact Resistance of Aerospace Transparent
1
Enclosures
ThisstandardisissuedunderthefixeddesignationF320;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope
1.1 This test method covers the determination of the impact
resistance of an aerospace transparent enclosure, hereinafter
called windshield, during hailstorm conditions using simulated
hailstones consisting of ice balls molded under tightly con-
trolled conditions.
1.2 The values stated in inch-pound units are to be regarded
as the standard. The values given in parentheses are for
information only.
1.3 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 appro-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For specific hazard
statements see Section 7.
2. Terminology
2.1 Definitions:
2.1.1 damage—any modification in visual properties or
integrity of a windshield as a result of hail impact including
scratches, crazing, delamination, cracks, or shattering.
2.1.2 ice ball—a frozen mass of water, with filler, that
simulates a natural hailstone in weight, size, and toughness.
2.1.3 impact angle—the angle between the ice ball flight
path and the target normal.
2.1.4 sabot—a plastic device for protecting the ice ball
whileinthelaunchtube.Onetypeofsabot(seeFig.1)consists
of a split polycarbonate rod containing a central cavity for
FIG. 1 Sabot Configuration
holding the ice ball. Each sabot half is designed to assure
aerodynamic separation from the ice ball after ejection from
the launch tube.
andangleandinaspecifiedpattern.Requirementsarespecified
for the ice ball, test specimen, procedure, and data acquisition.
3. Summary of Test Method
The ice ball is photographed in flight to verify its integrity.
3.1 The test method involves launching a series of ice balls
3.2 Requirements are specified for a particular apparatus
ofspecifiedsizesatasamplewindshieldataparticularvelocity
and test procedure, but options are permitted for certain areas.
However, it must be possible to demonstrate that the options
1
This test method is under the jurisdiction of ASTM Committee F07 on
used result in an ice ball at the test panel with the same size,
Aerospace andAircraft and is the direct responsibility of Subcommittee F07.08 on
consistency, and velocity as with the specified apparatus and
Transparent Enclosures and Materials.
procedure. Following are areas where options are allowed:
Current edition approved Mar. 1, 2005. Published March 2005. Originally
approved in 1978. Last previous edition approved in 1999 as F320–94 (1999). 3.2.1 Ice Ball Mold Material.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F320 – 05
FIG. 2 Launcher Design
3.2.2 Launcher—Any type of launcher is allowable as long high-qualityAISI 4130 seamless steel tubing, or equivalent, in
as the iceball reaches the test specimen at the correct speed. the annealed condition. The breech shall be made from AISI
The use of sabots and sabot material and geometry are 4130 steel rod, or equivalent, heat treated to a 160- to 180-ksi
optional. (1104- to 1242-MPa) ultimate tensile strength condition. The
3.2.3 Method of Determining Ice Ball Integrity. size of cavity to be used in the breech depends on the desired
3.2.4 Ice Ball Speed Measurement, Optional as long as test velocity (see Table 1). The breech plug, which locks the
accuracy standards are met. cartridge in place and contains the firing pin, shall be made of
3.2.5 Test Specimen Sizes—Those given are minimum. 4340 steel heat treated to a 160- to 180-ksi ultimate tensile
3.2.6 Safety—Safetymustsatisfythesafetystandardsofthe strength condition. The firing pin is actuated by a kinetic
test facility being used. impact air piston. Control is accomplished by an electrically
actuated air valve. For a 100-psi (0.69-MPa) air source, a
2 2
4. Significance and Use
0.75-in. (4.84-cm ) piston traveling 0.5 in. (13 mm) is used.
4.1 This test method may be used to determine the hail
5.5 Blast Deflector—Place a plate with a 4-in. (100-mm)
impact resistance of windshields for acceptance, design, ser-
diameterholeasshowninFig.3betweenthesabottrapandthe
vice, or research purposes. By coupling this method with the
first velocity measuring station. Then place a corrugated
installed angl
...
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