/^AcA/.'^^^ ^ 11 t 11 ' NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS WARTIME REPORT ORIGINALLy ISSUED September 191+2 as Restricted Bvilletin TESTS OF A STRESS-CARRYING DOOR IN COMPRESSICW By Robert Gottlieb Langley Memorial Aeronautical Laboratory Langley Field, Va. UNIVERSIP/ OF FLORIDA DOCUMENTS DEPARTMENT 120 MARSTON SCIENCE LIBRARY P.O. BOX 117011 GAINESVILLE, FL 32611-7011 USA [• 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 wax 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 - 253 Digitized by tine Internet Archive in 2011 witln funding from University of Florida, George A. Smathers Libraries with support from LYRASIS and the Sloan Foundation http://www.archive.org/details/testsofstresscarOOI Iii 0^ l>sooro\ NATIONAL ADVISOHY COMMITTEE FOR AERONAUTICS HSSTRICTED BULLETIN TESTS OF A STRESS-CARRYING DOOR IN COMPRESSION 3y Robert Gottliel) The results of torsional tests on a monocoque box containing a stress-carrying door were presented in ref- erence 1. The present p = per f^ives the results of bending tests on the snme box with the door on the compression side. The details of the box and the location of the ap- plied forces are shown in figure 1. Outside and inside views of the stress-carrying door are shown in figure 3. Vertical lo-^ds of lOCO, 3C00, 3000, and 4000 pounds were applied at the free end of th° box. The chordwise stress distribution at station 27.75 (see fig. l) is shown in figure 3 for the- case of cut-out, cut-out with door, and no cut-out. The effectiveness of a stress-carrying door depends on the intended function of the door. If the function of the door is considered to be that of reducing the maxiEUE cocpressive stresses around the cut-out, a meas- ure of the effectiveness of the door is the ratio of the stresses a/b. (See fig. 3.) If the function of the door is considered to be that of carrying load froni one end of the cut-out to the other, a measure of the effec- tiveness of the door is the ratio of the areas double-shaded area entire shaded area The entire shaded area represents the 1 opd-carry ing ca- pacity that wts lost when the cut-out was made; the double-shaded area shows the an^ount of this load-carrying capacity that v/as recox'-ered when the door was placed in the cut -out . In figure 4 these two m e a s u r e p of the effectiveness of the door in compression are plotted against the ap-olied load at the tip of the box. These curves indicate that the door becomes effective in carrying loads across the cut-out at a load of apiDro-yim -^ t ely IrOO pounds and that it becomes effective in reducing stresses at a load of approximately 23C0 potind;?. The effectiveness increases raoidly as greater loads are applied. The door is inef- fective at 1 ov/ loads "because of the clearance provided ■between the door and door frane to allow easy removal of the door at zero load. Before the door can hecome ef- fective in compression, the material on each side must he deformed sufficiently to tike up this clearanc?. Langley Memorial Aeronautical Lahoratory, ITational Adt^isory Comr.ittee for Aeronautics, Langley Field, Va. aE?EES>TCa 1. G-ottlie!:, Ho'bert: Tast of a St ross-Oarrying Door in Shear. ITaCA H.B., Aug. 1S42. NACA Fig. 2 bJ O o K O O o • o w z - — V «> ac — < o 1 I (0 I (9 NACA 2000 000 Fig, 3 4000 2000 • zooo (oOOO 4000 c/0 w EOOO O 3000 -Q V \j L o T] 0) "q. < 6 000 (oOOO 4 000 2 000 O 4000 No cut-out Cut-out Cut-out with door 10 40 50 20 30 Chord _, in, Hgure 3.- Chord wise stress distributicn ot station Z7.7^. ■NACA Fig. 4 2000 3000 Applied force, lli Figure 4.- Eff ectiveriess of loor. UNIVERSITY OF FLORIDA 3 1262 08106 504 6 'TP. nr •^^2611-7011 USA