1、F._.4LI)_-_, (i N.- _ _- _ _ / JNATIONAL ADVISORY AERONAUTICSMEMORANDUM REPORTfor theBureau of Aeronautics, Navy DepartmentEFFECT OF N0_AL PRESSURE ON THE CRITICALCOMPRESSIVE STRESS OF CURVED SHEETBy Norman RafelLangley MemorialAeronautlcal LaboratoryLangley Field, Va.qrFil_ : _r.j . ._-,2-7.T_,_:_,
2、 :_:“:. “ .?x_CLariFICATION r_ ,-.August 25, 1942_, /_ - .? 4-.,r“Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_EMORANDUM REPORTfor theBureau of Aeronautics, Navy DepartmentEFFECT OF NORMAL PRESSURE ON T_ CRITICALCOMPRESSIVE STRESS OF CURVED SHEET
3、By Norman RafelIn order to study experimentally the effect of normalpressure on the critical compressive stress for thin curvedsheet, two specimens were constructed, as shown in figures iand 2. These specimens are designated by their respectiverib spacings of lO inches and 30 inches.As shown in figu
4、re 3, each specimen was tested withflat ends in the 1,200,O00-pound-capacity testing machinein the NACA structures research laboratory. The loadinghead of this machine is laterally supported during testsby the heavy side colurm_s of the machine in such a manneras not to affect the accuracy of load m
5、easurement. Theends of the specimen were ground flat and parallel in aplaner specially adapted for this purpose. The detailedoperations of finishing the ends of the specimen and theloading of it were planned so as to give uniform straindistribution throughout the specimen; strain distributionduring
6、the test was checked by wlre-reslstance-type strain_ages,Normal pressure was applied by admitting compressedair into the specimen. A mercury manometer calibrated inProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- 3 -5. The compressive stress - normal
7、 pressure curve atwhich the buckles disappeared on unloading is always belowthe compressive stress - normal pressure curve at with thebuckles appeared. (See fig. 8.)6. The relationship between compressive stress andnormal pressure at which buckles disappeared is independentof whether the buckles wer
8、e made to disappear by increaseof normal pressure or decrease of comprossive stress.(See fig. 8.)Langley Memorial Aeronautical Laboratory,National Advisory Committee for Aeronautics,Langley Field, Va., August 25, 1942.Norman RafelAssistant Aeronautical Engineer.Approved:Elton W. Hiller,Head Mechanic
9、al Engineer.VDPProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_Gure L- Specimen wilh O-inch rib spocin 9.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_Joidiam r/vet_ Jp_ced ot _“_on out_iderlqnjej
10、 ond a.t f on in_/de ribs.! j-NATIONAL ADVISORYCOMMITTEE FOR AERONAUTICSFigure 2.- Specimen wilh DO-inch rib 5pocincj.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_t_nv,ouJv uo_ .,J.unno_ xuoel_av _V,OLLV, 3N I H 0 VMeNizsz AXi0VdVO ONnOd - 000e00
11、_l NIOIMOF_9 9NI0dS 1_ HONi-0( _ HJ. IM N3MI03d_ - -_ ungl._Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Ir|!Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_“ ,j:! ,_.Io_d ,:;:1ti ; : iii IcoM_,._io_Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.“ I 1 t,_t! o le_Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
