ASTM_F_1864_-_05_2010.pdf

Designation:F186405(Reapproved 2010)Standard Test Method forDust Erosion Resistance of Optical and Infrared TransparentMaterials and Coatings1This standard is issued under the fixed designation F1864;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the resistance of transparentplastics and coatings used in aerospace windscreens,canopies,and viewports to surface erosion as a result of dust impinge-ment.This test method simulates flight through a definedparticle cloud environment by means of independent control ofparticle size,velocity,impact angle,mass loading,and testduration.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility 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.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD1003 Test Method for Haze and Luminous Transmittanceof Transparent PlasticsD1193 Specification for Reagent WaterE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE168 Practices for General Techniques of Infrared Quanti-tative Analysis(Withdrawn 2015)33.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 mass loading,nthe mass of dust per unit of totalexposed surface area(including the sample holder)that im-pinges on the specimens.3.1.2 mean IR transmission,nfor the purposes of thisstandard,the average percentage of light transmitted by amaterial in the 8-to 12-m bandwidth.3.1.3 sweep time,nthe time required for one translationpass.3.1.4 translation pass,nthe translation of the specimenplatform from the vertical or horizontal limit to the correspond-ing vertical or horizontal limit.3.1.5 translation cycle,nthe translation of the specimenplatform from the vertical or horizontal limit to the correspond-ing vertical or horizontal limit and back to the initial vertical orhorizontal limit.Two translation passes are equivalent to onetranslation cycle.3.2 Symbols:As=reference surface area of specimen platform(cm2),Cc=simulated cloud concentration(g/m3),ho=percent haze before exposure,he=percent haze after exposure,m p=rate of particle mass impacting the reference surfacearea(g/min),m i=incremental mass loading(g/cm2),mT=total mass loading(g/cm2),N=number of increments,Vp=particle impact velocity(m/s),ts=sweep time(s),Te=optical or mean infrared(IR)transmission after expo-sure(%),To=optical or mean IR transmission before exposure(%),=impact angle(normal incidence=90),ti=exposure time(min)for loading increment i,i=incremental dust load(g/cm2)for loading increment i,=total dust load(g/cm2),h=change in percent haze,andT=change in optical or IR transmission.4.Summary of Test Method4.1 This test method consists of:(1)measuring and record-ing the light transmission properties,at visual or infraredwavelengths,of test coupons;(2)mounting the coupons in atest fixture;(3)exposing the coupons to a dust particle stream;1This test method is under the jurisdiction of ASTM Committee F07 onAerospace and Aircraft and is the direct responsibility of Subcommittee F07.08 onTransparent Enclosures and Materials.Current edition approved May 1,2010.Published June 2010.Originallyapproved in 1998.Last previous edition approved in 2005 as F1864 05.DOI:10.1520/F1864-05R10.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 and(4)remeasuring the light transmission properties to deter-mine changes in these properties.4.2 The dust particle stream simulates flight at a specifiedvelocity through a dust cloud of specified density.Simulation isaccomplished through control of particle size distribution,mean particle velocity,particle mass flow rate,and angle ofimpact.4.3 The degree of abrasion is measured by the amount ofchange in haze and luminous transmittance for materialstransparent in the visual wavelengths and by the amount ofchange in IR spectral transmission for materials transparent inthe infrared wavelengths.5.Significance and Use5.1 All materials on exterior aircraft surfaces are subject toabrasion from airborne particles of various sizes and shapes.Transparent materials are particularly vulnerable to abrasion,since their performance is based on their ability to transmitlight with a minimal amount of scatter.Scratches,pitting,an