^KcA-L-Z^^' ( NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS WARTIME REPORT ORIGINALLY ISSUED Au^st 19'<-2 as ReB trie ted Bulletin TESTS OF A STRESS- CARRYING DOOE IN SHEAR By Robert Gottlieb Langley Memorial Aeronautical Laboratory Langley Field, Va. university of florida :t . . o^.^:-.o^ _iBRARY 1-7011 USA NACA WASHINGTON NACA WARTIME REPORTS are reprints of papers originally issued to provide rapid distribution of advance research results to an authorized group requiring them for the wsir effort. They were pre- viously held under a security status but are now unclassified. Some of these reports were not tech- nically edited. All have been reproduced without change in order to expedite general distribution. L - 251+ /2V Ot^ ^^^ IfOi^sOH I 1-1 NATIONAL AEVISOny COMMITTEE FOP. AERONAUTICS RESTRICTED BULLETIN TESTS or A 3TRESS-CARRYI::G BOOR IN SHEAR 3y Robert Gottlieb A monoc OQue box with a stress-carrying door was made ani teste.-, in iors 1 on. •he details of this box and the location of the applied toro^ues are shown in figure 1. Outside and inside views of the strees- carryin<^ door are shown in figure 2. The results of the torsion tests are presented in figures 3, 4, and 5, In figure 3 are plotted torque- twist curves for the case of cut-out, cut-out v/ith door, and no cut-out. These curves show that a large part of the torsional stiffness lost by making a cut-out can be recovered by use of a stress-carrying door. This fact is more clearly revealed in figure 4 where the slopes of the curves in figure 3, which define the torsional stiffness, are plotted against the applied torque. The ratio b/a in this figure is .? measure of the effective- ness of the door in recovering the torsional stiffness lost v/hen the cut-out v;as made. This effectiveness va.ries with the ,'ipplicd torque, as shown in figure 5, If a stress-carrying door ani its frt-^ne are made sufficiently heavy, the torsional stiffness of the box with the door can be made greater than the torsional stiffness of the box without the cut-out. In the speci- men of firure 1, tnc stress-carrying door was made '.'ith the same gage of skin as v/as used in the box and with stiffeners of less depth than the stiffeners in the box. The smaller stiffentjrs in the door v/ere used in order to make the total thickness of the door approximately the same as the total thickness of the skin and the stiffeners in the box. Langley Memorial Aeronautical Laboratory, National Advisory Committee for Aeronautics, Langley Field, Va. , NACA Fig. 1 NACA Fip. 2 ^ 0) -H 00 o o •d bO a •H cd o I CD CO 0) U *> CO C\2 CD •H Pig. 3 100 X IC" 80 •■;' 60 0) u o EH 40 i — 20 // P / i/ / / / n-- / X / -/^-l— ' / / ! /i / / ^- r--7 1— -7^ // /! i // :/ / ! "c? Ijo cut-out I O C\it-out with door ' Q C-jt-out /// 4^: /H ■ .002 .004 .006 Tvrist, radian .COS Pigvire 3.- Torque- t'vist, curves for "box. Digitized by tlie Internet Arcliive in 2011 witli funding from University of Florida, George A. Smathers Libraries with support from LYRASIS and the Sloan Foundation http://www.archive.org/details/testsofstresscarOOIang KACA Fig. 4 24 :v 10^ 20 •H r-H 1 tn o •H +^ CO I I o o EH 16 ITo c;vit-out 1 ' 1 1 ■ ■ ■ 1 Oat-out with ioo 1 ^' X \ ^^ ^__^ " \\ ^ \ a Cut- out 1 11 y ■ ' 20 40 50 Torque, in.-ll) 80 X 103 Figure 4.- Torsional stiffness of to:-;. MCA Fig. 5 l.Oi .. r,i > •H -P C C) Vl ^0 60 TorquG, in. -It £0 :•: 10- Piguro o.- Effectiveness of door. UNIVERSITY OF FLORIDA 262 08106 506 1 UNIVERSITY OF FLORIDA DOCUMENTS DEPARTMENT 1 20 MARSTON SCIENCE LIBRARY RO. BOX 117011 GAINESVILLE. FL 32611-7011 USA 1 .