1、a71 a15a15NATIONAL _ADVISCW COMMITEE FOR AERONAUTS ORIGINALLYISSLEDApril 19+4 asRestricted BulletlnL4DWSOME STFU!NGTHTESTS OF STIFFENEDCURm SEEE?ISLOADEDIN SHEARBy Patrick T. ChiaritoLangley Memorial AeronauticalLaboratoryLangley Field, Va.NACA WARTIME REPORTS arereprintsofpapersoriginallyissuedtoQr
2、oe Eidl%stributionofadvanceresearchresultstoan authorizedgrouprequiringthem forthewar effort.They were pre-viouslyheldundera securitystatusbutarenow unclassified.Some ofthesereportswere nottech-nically”edited.Allhave been reproducedwithoutchangeinordertoexpeditegeneraldistribution.L- 2:9Provided by
3、IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Illllllmmimllllll311760143336s2._ _ - -NACA RB NO. L4W$!?ATIC)IW AtWIWRf COMMITTEE IfoR AERONAUTICS.-w., . . -.R7 it wasconsidered desirable to publish, before completion ofthe projects such test results as might b
4、e of somedirect usefulness to the destgner. Tha present paperdescribes the spec$mens tested to date arylgives theobserved skin-buckling stresses and tbe ultlmatestrengths developed.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 3JACARB NO. L4M9,a7
5、1SYMBOLSt thickness of skin or web, inchesd longitudinal distance between adjacent rin double angles were usedfor tineheavier beams. The shell specimens had threelongitudinal skin splices located under stringers 120apart.Provided by IHSNot for ResaleNo reproduction or networking permitted without li
6、cense from IHS-,-,-NACA RB 0 . L4D29 3The stringers.weneplacedonthe outstde of thesheet because floating rings were consj.deredundds-irablefor the beam tests and because the tests of reference 3indicated that tests of specimens with notched rings orwith intercostal stiffenerswould not yield resultsw
7、hich could be generalized.As indtcated In figure 1, the beams as well as theshells were equipped with special root fittings thatwere used to attach the test specimens to a heavy steelstructure. The tip fitting of the beams was essentiallya steel plate that pernitted the test load to be appliedat the
8、 estimated shear centr of the cross section.Both beam flanges were supported against possible lateraldeflections at intervals ofapproximately 15 Inches alongthe span. The tip ilttlngof the shells was a heavysteel ring of a.le section. Torque was applied to thisrhg a a couple by mrls of 8 double bell
9、 crank.The test reslltsare summarized in table 2. Theload nt which the skeet bsgnn to show shear buckles wasdetem+.ned by obsorvin the reflection in the sheet ofa stra?ht edge while it was bellgrolled over thecurved surfncc of the sheet in a direction perpendicularto the expected folds. Comparisons of the bucklinx;x. .,. , , . . -Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.1111111111111111Iimmiilllllllllllllllll31176014393582Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
