Research abstracts

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Title:
Research abstracts
Physical Description:
93 v. : ; 27 cm.
Language:
English
Creator:
United States -- National Advisory Committee for Aeronautics
Publisher:
National Advisory Committee for Aeronautics
Place of Publication:
Washington, D.C
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irregular
completely irregular

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Subjects / Keywords:
Aeronautics -- Abstracts -- Periodicals   ( lcsh )
Aeronautics -- Research -- Abstracts -- Periodicals   ( lcsh )
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serial   ( sobekcm )
federal government publication   ( marcgt )
abstract or summary   ( marcgt )

Notes

Statement of Responsibility:
National Advisory Committee for Aeronautics.
Dates or Sequential Designation:
Abstracts no. 1 (June 15, 1951)-no. 93 (Nov. 30, 1955).

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 001469326
notis - AGY1019
oclc - 01471285
lccn - 86657025
issn - 0499-9274
Classification:
lcc - TL501 .U5895
System ID:
AA00009235:00048

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Full Text


National Advisory Committee for Aeronautics


Research Abstracts


NO.84


JUNE 9, 1955


CURRENT NACA REPORTS


NACA Rept. 1182

COMPARISON OF EFFECTIVENESS OF
CONVECTION-, TRANSPIRATION-, AND FILM-
COOLING METHODS WITH AIR AS COOLANT.
E. R. G. Eckert and John N. B. Livingood. 1954.
it, 17p. diagrs. (NACA Rept. 1182. Formerly
TN 3010)

Material necessary for a comparison of the cooling
requirements of film and transpiration cooling with
conventional convection cooling is presented. Both
Laminar and turbulent flow, with and without radia-
tion, are considered for a flat plate. The i"
ity of transpiration coolin v 96enffr both
laminar and turbulent flo U
ri-
\ I'rr' *" i

\ \ '--

NACA RM L55D15a .c. : '

SOME OBSERVATIONS ON SATIC
STRENGTH DUE TO FATIGUE CRACKS. Walter Ulg
and Herbert F. Hardrath. May 1955. 8p. diagrs.
(NACA RM L55D15a)

Static tensile tests were performed on simple notched
specimens containing fatigue cracks. Four types of
aluminum alloys were investigated: 2024-T3 (for-
merly 24S-T3) and 7075-T6 (formerly 75S-T6) in
sheet form, and 2024-T4 (formerly 24S-T4) and
7075-T6 (formerly 75S-T6) in extruded form. The
cracked specimens were tested statically under four
conditions: unmodified and with reduced eccentricity
Sof loading by three methods. Results of static tests
on C-46 wings containing fatigue cracks are also
reported.





NACA RM L55D15b

PRELIMINARY INVESTIGATION OF THE FAILURE
OF PRESSURIZED STIFFENED CYLINDERS.
Norris F. Dow and Roger W. Peters. May 1955.
14p. diagrs., photos., tab. (NACA RM L55D15b)

Tests were made of stiffened cylinders of 2024
aluminum alloy under internal pressure and cyclic
torsion. Both gradual and explosive types of failures
occurred. The type of failure depended upon the hoop
stress and structural configuration, particularly on
the ratio of area in rings to associated skin area.


NACA TM 1379

A METHOD OF QUADRATURE FOR CALCULATION
OF THE LAMINAR AND TURBULENT BOUNDARY
LAYER IN CASE OF PLANE AND ROTATIONALLY
SYMMETRICAL FLOW. (Em Quadraturverfahren
zur Berechnung der laminaren und turbulenten
Reibungsschicht bei ebener und rotationssymmetri-
scher Stromung). E. Truckenbrodt. May 1955.
40p. diagrs. (NACA TM 1379. Trans. from
Ingenieur-Archiv, v.20, no. 4, 1952, p. 16-228).

For calculation of the characteristic parameters of
the boundary layer (momentum-loss thickness and
form parameter for the velocity profile), two quad-
rature formulas are given which are valid for the
laminar as well as for the turbulent state of flow.
These formulas cover both the two-dimensional and
the rotationally symmetrical case. The calculation
of the momentum-loss thickness is carried out by a
' simple integration of the rgem. The
equation for the form ebramete. -i sobtytned
coupling of the mroment4 pfiheorem'ith.the energy
theorem. Knowled$'e o the derivatives'of Ie veloc-
ity distribution ano fhiadius of the bkdyn along
the length x is n t ess 0..


NACA TN 3296 _t

SEPARATION, STABILITY, AND OTHER PROPER-
TIES OF COMPRESSIBLE LAMINAR BOUNDARY
LAYER WITH PRESSURE GRADIENT AND HEAT
TRANSFER. Morris Morduchow and Richard G.
Grape, Polytechnic Institute of Brooklyn. May 1955.
45p. diagrs., 6 tabs. (NACA TN 3296)

A theoretical study is made of the effect of pressure
gradient, wall temperature, and Mach number on
laminar boundary-layer characteristics and, in
particular, on the skin-friction and heat-transfer
coefficients, on the separation point in an adverse
pressure gradient, on the wall temperature required
for complete stabilization of the laminar boundary
layer, and on the minimum critical Reynolds number
for laminar stability. A simple and accurate method
of locating the separation point in a compressible
flow with heat transfer is developed.


NACA TN 3314

A TECHNIQUE UTILIZING ROCKET-PROPELLED
TEST VEHICLES FOR THE MEASUREMENT OF
THE DAMPING IN ROLL OF STING-MOUNTED
MODELS AND SOME INITIAL RESULTS FOR DELTA
AND UNSWEPT TAPERED WINGS. William M.
Bland, Jr. and Carl A. Sandahl. May 1955. 25p.
diagrs., photos., tab. (NACA TN 3314. Formerly
RM L50D24)


*AVAILABLE ON LOAN ONLY
ADDRESS REQUESTS FOR DOCUMENTS TO NACA, 1512 H ST, NW.. WASHINGTON 95, D C, CITING CODE NUMBER ABOVE EACH TITLEr
THE REPORT TITLE AND AUTHOR


ez. 13.2'

IV err*






2



A free-flight test technique with which the damping
in roll of sting-mounted models can be measured
over the high subsonic, transonic, and supersonic
speed range with rocket-propelled test vehicles is
described. Initial results for delta and unswept
tapered wings are presented and compared with
theory.





NACA TN 3367

A DYNAMIC-MODEL STUDY OF THE EFFEC r OF
ADDED WEIGHTS AND OTHER STRUCTURAL VAR-
IATIONS ON THE BLADE BENDING STRAINS OF AN
EXPERIMENTAL TWO-BLADE JET-DRIVEN HELI-
COPTER IN HOVERING AND FORWARD FLIGHT.
John Locke McCarty and George W. Brooks. May
1955. i. 47p. diagrs., photo., 6 tabs. (NACA
TN 3367)

An experimental investigation of the rotor system of
a 1/10-scale dynamic model of an experimental two-
blade jet-driven helicopter to determine the effect of
various changes in the design configuration on the
blade bending strains has been conducted. These
changes included the addition of different amounts of
concentrated weight to the blades at various radial
and chordwise locations and variations in the design
counterweight locations, as well as changes in the
blade-pitch-control stiffness. The blade bending
strains could be materially reduced by adding
concentrated weights to the blades in such a manner
as to minimize resonance conditions or to induce
favorable coupling of blade bending and torsion
deformations.






NACA TN 3394

LOW-SPEED INVESTIGATION OF THE EFFECTS OF
ANGLE OF ATTACK ON THE PRESSURE RECOVERY
OF A CIRCULAR NOSE INLET WITH SEVERAL LIP
SHAPES. James R. Blackaby. May 1955. 30p.
diagrs., photo. (NACA TN 3394)

An investigation was made at a free-stream Mach
number of 0.237 of the effects of lip bluntness and
profile on the total-pressure recovery of a circular
nose inlet in a ducted body of revolution at angles of
attack up to 250. A sharp inlet lip having a wedge
angle of 7-1/2o was tested in addition to two circular-
arc lips ard two lips with elliptical profiles, all of
which were formed within the 7-1/20 angle of the
sharp lip.





NACA TN 3395

ON THE CALCULATION OF THE 1-P OSCILLATING
AERODYNAMIC LOADS ON SINGLE-ROTATION
PROPELLERS [N PITCH ON TRACTOR AIRPLANES.
Vernon L. Rogallo and Paul F. Yaggy. May 1955.
28p. diagrs., photo. (NACA TN 3395)


NACA
RESEARCH ABSTRACTS NO. 84



A procedure for calculating the 1- P oscillating aero-
dynamic thrust loads on single-rotation, tractor
propellers in pitch at zero yaw is developed and is
evaluated. Application of the procedure requires
knowledge of only the upflow angles at the horizontal
center line of the propeller disk. The apphcability
of the procedure to various airplane configurations
is discussed.



NACA TN 3417

MEASUREMENTS OF FREE-SPACE OSCILLATING
PRESSURES NEAR A PROPELLER AT FLIGHT
MACH NUMBERS TO 0.72. Arthur W. Vogeley and
Max C. Kurbjun. May 1955. 24p. diagrs., photos.,
tab. (NACA TN 3417)

Limited measurements have been made of the free-
space oscillatory pressures near the tips of a propel-
ler at flight Mach numbers up to 0.72. Measure-
ments were made at a single radial station and at
three axial positions (ahead of, in the plane of, and
behind the propeller disk). Comparisons, showing
the effects of forward Mach number on oscillating
pressures, are made with the Garrick-Watkins
theory (NACA TN 3018).




NACA TN 3424

AERODYNAMIC CHARACTERISTICS OF SEVERAL
6-PERCENT-THICK AIRFOILS AT ANGLES OF
ATTACK FROM 0 TO 200 AT HIGH SUBSONIC
SPEEDS. Bernard N. Daley and Douglas R. Lord.
May 1955. 57p. diagrs.. photos. (NACA TN 3424.
Formerly RM L9E 19)

Aerodynamic characteristics obtained from two-
dimensional tests of eight 6-percent-thick symmet-
rical airfoils of the supersonic and subsonic type
are presented at angles of attack from 00 to 200 and
at Mach numbers from 0.3 to about 0.9. Results in-
dicate generally improved characteristics for the
circular-arc and wedge-type airfoils when the maxi-
mum thickness was located forward. The variations
with Mach number of the lift, drag, and pitching-
moment coefficier.ts are generally similar for those
supersonic- and subsonic-type airfoils tested.



NACA TN 3425

SOME CALCULATIONS OF THE LATERAL RE-
SPONSE OF TWO AIRPLANES TO ATMOSPHERIC
TURBULENCE WITH RELATION TO THE LATERAL
SNAKING PROBLEM. John D. Bird. May 1955.
24p. diagrs., 2 tabs. (NACA TN 3425. Formerly
RM L50F26a)

Results of calculations of the lateral response to
representative time histories of atmospheric turbu-
lence for two airplanes having widely dillerent dy-
namic properties indicate that, under the proper
conditions, atmospheric turbulence can initiate and
maintain a lateral hunting oscillation of an airplane,
and that this oscillation can be fairly regular in both
amplitude and frequency. This effect is more pro-
nounced for lightly damped airplanes.





NACA
RESEARCH ABSTRACTS NO. 84


NACA TN 3427

THEORETICAL INVESTIGATION OF A
PROPORTIONAL-PLUS-FLICKER AUTOMATIC
PILOT. Ernest C. Seaberg. May 1955. 53p.
diagrs., photo., tab. (NACA TN 3427. Formerly
RM L50119)

An analysis has been made of the stability of a super-
sonic canard airframe and a proportional-plus-
flicker autopilot. Essentially, this autopilot main-
tains a zero reference about which the output is pro-
portional to the input and a flicker response over-
rides this proportional response at a fixed angle of
gimbal displacement on either side of the zero
gyroscope reference. The analysis consists of an
investigation of the calculated transient responses
based on the variation of the autopilot and aero-
dynamic parameters. The calculations are based on
the assumption that the proportional part of the
system either contains a perfect autopilot or is the
actual autopilot frequency response approximated by
mathematical transfer function.





NACA TN 3433

TOTAL LIFT AND PITCHING MOMENT ON THIN
ARROWHEAD WINGS OSCILLATING IN SUPERSONIC
POTENTIAL FLOW. H. J. Cunmngham. May 1955.
43p. diagrs., 4 tabs. (NACA TN 3433)

Total lift and moment coefficients are given for thin
arrowhead wings oscillating in pitch and vertical
translation which extend to the fifth power and to the
third power of the frequency for the subsonic and
supersonic-leading-edge cases, respectively. These
expressions are sufficiently accurate to make them
potentially useful in flutter applications.




NACA TN 3438

ON THE KERNEL FUNCTION OF THE INTEGRAL
EQUATION RELATING LIFT AND DOWNWASH DIS-
TRIBUTIONS OF OSCILLATING WINGS IN SUPER-
SONIC FLOW. Charles E. Watkins and Julian H.
Berman. May 1955. 43p. (NACA TN 3438)

A suitable form of double potential that serves as a
basis for deriving the kernel function for supersonic
flow, corresponding to the kernel function for sub-
sonic flow presented in NACATN 3131, is derived by
using a cutoff or unit function. A treatment similar
to that made for the subsonic kernel is made for the
kernel [unction for supersonic flow. The singulari-
ties are isolated and discussed, and the kernel func-
tion is shown to lead to correct results for two-
dimensional flow, and to reduce properly to the sonic
case.



NACA TN 3439

ANALYSIS OF EAR FORMATION IN DEEP-DRAWN
CUPS. Arthur J. McEvily, Jr. May 1955. 7p.
diagrs. (NACA TN 3439)


3



A review of the literature on deep drawing and on
amsotropy of metals indicates that no direct cor-
relation has been established between the number and
location of the ears on deep-drawn cups and the pre-
ferred crystallographic orientation of the blank mate-
rial. In the present paper, a method for predicting
hearing behavior is proposed which is based on the
plastic properties of single crystals and a knowledge
of the preferred orientation of the blank material.
The proposed method of prediction is in satisfactory
agreement with reported experimental results.


NACA TN 3440

HOVERING FLIGHT TESTS OF A FOUR-ENGINE-
TRANSPORT VERTICAL TAKE-OFF AIRPLANE
MODEL UTILIZING A LARGE FLAP AND EXTEN-
SIBLE VANES FOR REDIRECTING THE PROPEL-
LER SLIPSTREAM. Louis P. Tosti and Edwin E.
Davenport. May 1955. 26p. diagrs., photos., Lab.
(NACA TN 3440)

An investigation of the take-off, landing, and hover-
ing flight characteristics of a four-engine-transport,
vertical take-off airplane has been conducted with a
remotely controlled free-flight model. The model
had four propellers distributed along the wig with
thrust axes parallel to the fuselage axis. In order to
produce direct lift for hovering flight the propeller
slipstream was deflected downward about 700 by a
full-span 65-percent-chord flap deflected 900 and
eight extensible vanes arranged above the wing in a
cascade relation.



NACA TN 3441

AN NACA VANE-TYPE ANGLE-OF-ATTACK IN-
DICATOR FOR USE AT SUBSONIC AND SUPERSONIC
SPEEDS. Jesse L. Mitchell and Robert F. Peck.
May 1955. 8p. diagrs., photo. (NACA TN 3441.
Formerly RM L9F28a)

A description is presented of a vane-type angle-of-
attack indicator developed by the NACA for use at
supersonic and subsonic speeds. A brief history of
the development and a wind-tunnel calibration are
given together with a discussion of the corrections to
be applied to the indicated readings.



NACA TN 3442

A PRELIMINARY INVESTIGATION OF AERODYNA-
MIC CHARACTERISTICS OF SMALL INCLINED AIR
OUTLETS AT TRANSONIC MACH NUMBERS.
Paul E. Dewey. May 1955. 21p. diagrs., photos.
(NACA TN 3442. Formerly RM L53C10)

The aerodynamic characteristics of several outlets
with inclined or curved axes discharging air into a
transonic stream have been investigated. The data
presented herein show the discharge coefficient of
such outlets and the static-pressure distribution in
the vicinity of the outlets for several values of
stream Mach number and discharge flow parameter.
Tuft observations, showing the vortex formation
caused by the outlet discharge from a perpendicular
and an inclined outlet, are also presented.






4



NACA TN 3444

FRICTION, WEAR, AND SURFACE DAMAGE OF
METALS AS AFFECTED BY SOLID SURFACE
FILMS. Edmond E. Bisson, Robert L. Johnson,
Max A. Swikert and Douglas Godfrey. May 1955.
60p. diagrs., photos., tab. (NACA TN 3444)

A summation is presented of NACA results obtained
from friction and wear investigations from 1946 to
1954. The results are consistent with theoretical
predictions that solid surface films of low shear
strength can serve to reduce both friction and sur-
face damage. Metallic oxides can have very marked
effects. Wear studies show that the ability of mate-
rials to form surface films is an important factor in
wear. Solid lubricants (MoS2 and graphite) are
beneficial under severe operating conditions, includ-
ing temperatures approaching 10000 F; both mate-
rials are, however, subject to oxidation at these
temperatures.



NACA TN 3454

EFFECT OF A DISCONTINUITY ON TURBULENT
BOUNDARY-LAYER-THICKNESS PARAMETERS
WITH APPLICATION TO SHOCK-INDUCED SEPARA-
TION. Eli Reshotko and Maurice Tucker. May 1955.
21p. diagrs. (NACA TN 3454)

The problem of shock-induced turbulent boundary-
layer separation was analyzed by an approximate
method. This method is based on a moment-of-
momentum equation and calculates the change of
boundary-layer-thickness parameters and form fac-
tor caused by a discontinuity where effects of friction
can be neglected. The form of the result suggests
that the Mach number ratio across the shock is a
characteristic parameter for defining shock-induced
separation. The method is also used to estimate the
effects of mass transfer on the boundary-layer-
thickness parameters for zero pressure gradient.




BRITISH REPORTS




N-36843*

Royal Aircraft Establishment (Gt. Brit.)
THE USE OF QUARTZ IN THE MANUFACTURE OF
SMALL DIAMETER PITOT TUBES. J. R. Cooke.
December 1954. 15p. diagrs., photos., tab. (RAE
Tech. Note Aero 2325)

This note describes the method of manufacture of
small quartz-tipped pitot tubes (down to 0.005 in.
outside tip diameter) which have been used success-
fully for boundary-layer measurements on small
models in a supersonic wind tunnel. Tests have been
made (a) of the effects of taper and end finish on the
accuracy of measurement and (b) of the effect of the in-
side diameter of the tip (for a standard taper) on
response rate. For a given inside tip diameter, the
tapered quartz tubes gave a faster response rate
than the stainless steel hypodermic tubes previously
used.


NACA
RESEARCH ABSTRACTS NO. 84


N-36849*

Aeronautical Research Council (Gt. Brit. I
TESTS RELATED TO THE EFFECT OF PROFILE
SHAPE AND CAMBER-LINE ON COMPRESSOR
CASCADE PERFORMANCE. S. J. Andrews. 1955.
23p. diagrs. (ARC R & M 2743; ARC 13.207.
Formerly NGTE R. 60)

Three shapes were chosen for comparison with the
airfoil. They were the flat plate with rounded leading
and trailing edges, a flat plate with sharpened leading
and trailing edges, and an approximately biconvex
shape. A representative cascade shape was chosen
and four cascades with the lour sections mounted on
circular-arc camber lines were made up. In addition,
two cascades were made up on paraol ic arcs. The
main conclusions are that tne approximately biconvex
profile is superior to the airioil at Mach numbers
above 0.75, and that the circular arc camber line is,
on the whole, superior to the parabolic arc. The
"plate" blades with blunt leading and trailing edges
are poor in performance, but the "plate with
sharpened edges" is reasonably good.


N-36850*

Aeronautical Research Council IGt. Brit.)
AERODYNAMIC FORCES ON RECTANGULAR
WINGS OSCILLATING IN A SUPERSONIC AIR
STREAM. W. E. A. Acuni. 1954. 28p. diagrs.,
2 tabs. (ARC R & M 2763. Formerly ARC 13,286;
FM 1465; 0.879; S& C 2418)

In this report linearized theory is used and numerical
solutions are derived by the method of "relaxation. "
The problem reduces to one of finding a series of
conical flow solutions. Moment coefficients for a
range of Mach numbers and various frequency pa-
rameter values were calculated. For a range of
Mach numbers in two-dimensional flow, the aero-
dynamic damping for pitching oscillation can be
negative for certain positions of the axis of pitch
oscillation, and this implies instability. The re-
sults of this report show that aspect ratio has a
stabilizing effect for axes less than about 0.7 of the
chord downstream of the leading edge. but has the
opposite effect for axes nearer Iman this to the
trailing edge.


N-36851*

Aeronautical Research Council (Gt. Brit.)
THE SECONDARY FLOW IN CURVED PIPES. H. G.
Cuming. 1955. 17p. diagrs.. 3 labs. (ARC
R & M 2880. Formerly ARC 13.979; FM 1558)

The Navier-Stokes equations ior the flow of a viscous
incompressible fluid through curved pipes of different
sections are solved in power series of thecurvature
of the pipe. The solution is given as far as the first
power of the curvature for the case of an elliptic
section and a discussion given of the effect of the
aspect ratio of the pipe on the intensity of the sec-
ondary flow. The solution is also given to the first
power of the curvature for the case of a square sec-
tion and as far as the second power of the curvature
for the case of flow through a curved pipe of circular
section when suction proportional to the curvature is
applied at the walls. The result shows that with the
particular distribution of suction considered the
diminution in flux through a curved pipe may be al-
most entirely eliminated.






NACA
RESEARCH ABSTRACTS NO. 84


N-36873'

Forest Products Research Lab. (Gt. Brit.)
TRIALS OF TIMBER FOR PLYWOOD MANUFAC-
TURE. ADWEA PACHYLOBUS BARTER GOLD
COAST. (48 POUNDS PER CUBIC FOOT AT 15 PER
CENT MOISTURE CONTENT) APPENDIX B:
STRENGTH TESTS ON ADWEA PLYWOOD. W. T.
Curry. APPENDIX C: TESTS DESIGNED TO
COMPARE THE LIMITING RADIUS OF CURVATURE
IN THE BENDING OF ADWEA IPACHYLOBUS
BARTERI) 3-PLY WITH THOSE OF CANADIAN
YELLOW BIRCH IBETULA LUTEA). N. Turner.
(PROGRESS REPORT TWENTY-FIVE) January
1955. 21p. 6 tabs. I Forest Products Research Lab.)

Earlier tests had indicated that Adwea plywood pos-
sessed strength properties similar to those of
Canadian birch. It was agreed by the Plywood Re-
search Panel that tests to confirm this were most
desirable, and that at the sane time, an assessment
should be n.ade of the potentialities of the species for
general plywood manufacture. Results of these
tests and some comparisons with Canadian yellow
birch are presented in this report.





UNPUBLISHED PAPERS




N-37178'

HELICAL VORTICES AND CYLINDRICAL BOUND-
ARIES OF CIRCULAR CROSS SECTION. (Rasen uzu
to Ento Kyokai). Hisawo Takeyama. 8p. (Trans.
from Oyo Rigaku. v. 3, no. 13. Aug.. 1949. p. 6-8)

The velocity potential of helical vortices inr the
cylindrical boundaries, whose cross sections are
circles coaxial with the vortices. is obtained in
order to estimate the tip losses and body inter-


5



ference for axial blowers or propellers. In the case
of the fixed boundary, the circulation is increased
near the tip: but for the free boundary, it is de-
creased. It is also shown that the inner and outer
boundaries can be treated separately in the usual
blowers.


N-37216'

BREAKING DOWN OF CRYSTAL BLOCKS AND
APPEARANCE OF MLCROSTRESSES IN THE METAL
DURING PLASTIC DEFORMATION. (Droblenie
kristallicheskikh blokov i razvitie mikronapryazhenii
v metalle pri plasticheskoi deformastsui). B. M.
Rovinskil and L. M. Rybakova. 7p. diagrs. (Trans.
from Akademiya Nauk SSSR Otdelenie Tekhnicheskikh
Nauk, Izvestiya, no. 10, Oct.,1952, p.1483-1487)

The question as to whether the breaking up of the
regions which had been dispersed regularly into a
lattice called blocks or the appearance and develop-
ment of microstres-es actually takes place, domi-
nates, or causes the regular growth of the width of
the interference lines as a function of the magnitude
of the residual deformation during plastic deforma-
tion has not been answered sufficiently. This pres-
ent paper is concerned with the character of the pro-
cesses in steel for simple tension.


N-37217'

INTEGRAL EQUATIONS OF CONSTRAINED
TORSION AND STABILITY OF THIN-WALLED RODS.
(Integralnye uravneniya stesnennogo krucheniya i
ustoichivosti tonkostennykh sterzhnei).
V. V. Bolotm. 7p. (Trans. from Prikladnaya Mat.
i Mekhanika, v.17, no.2, Mar.-Apr.,1953, p.245-248)

The problem of the strength of thin-walled rods is
reduced to an integral equation. The computation of
the critical parameters of the load is affected by the
method of successive approximations and also by the
method of approximate integration.


NACA-Langley 6-9-55 4M



































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