1、NASA Contractor Report 172425 ANTEBIOR NOISE BCCZL: CSEIIS EAEUAL FOB CCBPETER FROGEAL Einal BeCOKt (Eclt, Eeranek, and lieuran, Inc.) 55 E CSCL 20A Unclas . Propeller Aircraft Interior /n/-7/ Noise Model - Users Manual 3-813- for Computer Program E.G.Wilby and L.D.Pope Bolt Beranek and Newman Inc.
2、Canoga Park, CA 91303 Contract NAS 1-15782 JANUARY 1985 . I January 31, 1987 Date for general release National Aeronautics and Space Administration Langley Research Center HamDton Vlrglnia 23665 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TABLE O
3、F CONTENTS Section 1.0 SUMMARY . 2.0 INTRODUCTION Page 1 2 3.0 MODELS 0 4.0 OVERALL PROGRAM DESCRIPTIONS. e 15 5.0 INPUT DATA . 113 5.1 Program CYL2D. . 18 5.1.1 Input Data. . 18 5.1.2 Output File, Tape 11. . . . . 18 5.1.3 Printed Output. . 18 5.2 Program MRP. 19 5.2.1 Input Data. . 19 5.2.2 Output
4、 File Tape 7. . 25 5.2.3 Printed Output. . 25 5.3 Program MRPMOD . 26 5.3.1 Input Data. . 26 5.3.2 Input Files . 27 5.3.j Output File, Tape 9 . 27 5.3.4 Printed Output. . 28 5.4 Program PAIN 28 5.4.1 Input Data. . 28 5.4.2 Input Files . 35 5.4.3 Printed Output. . 35 -i- Provided by IHSNot for Resale
5、No reproduction or networking permitted without license from IHS-,-,-TABLE OF CONTENTS (Continued) Section Page 6.0 CONTROL CARDS FOR EXECUTING THE PROGRAM . . . 38 6.1 Control Cards and Data for Program CYL2D . . . 39 6.2 Control Cards and Data for Program MRP . . . . 40 6.3 Control Cards and Data
6、for Program MRPMOD. . . 44 6.4 Control Cards and Data for Program PAIN. . . . 45 REFERENCES 47 APPENDIX A - LIST OF SYMBOLS A- 1 -11- I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-LIST OF FIGURES Figure Page 1. Propeller Aircraft Interior Noise M
7、odel . . . . 3 2. Propeller and Fuselage Surface Point Geometry . 4 3. Grid Used for Propeller Noise Predictions . . . 5 4. Flow Chart for Programs . . . . . . . . . . . . 17 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1.0 SUMMARY A computer prog
8、ram entitled PAIN (an acronymn for Propeller - Aircraft - Interior Noise) has been developed to permit calculation of the sound levels in a model of a cabin of a propeller-driven airplane. The model fuselage is a cylinder with a structurally integral floor. The cabin sidewall and floor are stiffened
9、 by ring frames, stringers and floor beams of arbitrary configura- tions. The cabin interior is covered with a trim (i.e., insulation with a lining) to increase the sidewall sound isolation and provide absorption in the cabin. The propeller noise of concern is actually a series of tones that occur a
10、t the blade passage frequency and at integral multiples of that frequency (i.e., at its harmonics). The program permits the calculation of the space-average interior sound levels for the first ten (10) harmonics of a propeller (of any design) rotating alongside the fuselage. The input data required
11、by the program include the mechanical and acoustical properties of the fuselage structure and sidewall trim. Also, the precise propeller noise signature must be defined on a grid that lies in the fuselage skin. The propeller data have to be generated with a propeller noise prediction program for exa
12、mple, the NASA Langley ANOPP program l). Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2.0 INTRODUCTION The present program mechanizes an analytical model presented in Reference 2. Details of the underlying theory on which this program is based are
13、 available in that report. The two primary elements of the interior noise model are the fuselage and the propeller (Figs. 1 and 2). The fuselage consists of a cylinder stiffened by ring frames and stringers, and a floor that is structurally an integral part of the fuselage. The cabin space is the vo
14、lume above the floor. The interior surface of the cabin (sidewall) is finished out with a trim consisting of insulation covered with a lining. The propeller rotates about an axis parallel to the centerline of the fuselage. The model can be used to predict the space average sound levels in the cabin
15、space for each of the various harmonics of the propeller (up to a maximum of ten (10) harmonics). The present model works with the pressure time histories (sig- natures) as defined over the fuselage at a number of closely spaced points on a grid that lies in the fuselage skin , (Fig. 3). The pressur
16、e signatures are input as Fourier series that define the amplitudes and phases of each of the harmonics of the propeller (at each location on the grid). The fuselage structural modes are developed for the case of a stiffened cylinder with a floor partition. The structural properties of the cylinder
17、and floor are required as input data. The structural modes are described by the computed resonance frequencies and mode shapes, and by associated structural loss factors. The loss factors of the modes of a bare fuselage must be input and must come from measurements (or be estimated). When trim is in
18、stalled on the sidewall, the structural losses increase due to the trims presence against the sidewall and this is computed for the particular trim installation. -2- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N 0 E p? 0 - p? w c Z - t a p? u p?
19、- a w A A w a. 0 = (na/18)kp-kl kp is the k index of the grid point (k,R) = (kp,l), that is, where the coordinate XI penetrates the fuselage. For example, for kmax = 16 as in Fig. 3, setting kp = 8 roughly centers the grid longitudinally about the propeller plane. Note that the value of (1a/18).k -
20、13 cannot P -8- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-exceed z P such that (18) x kmax-l Shear modulus. For isotropic materials, If Gxe is blank, it is computed using G = E/2(l+u) Thickness of shell (m). Includes ttsmeared-outtt stiffener a
21、reas. Shell mass/unit area (kg/m2) inc lud ing masses. smear e d-ou t s t iff ene r Radius of shell Length of shell Dis=y - stringer E (t3-ti3) (Nom) X 12 (1-u2) Additional bending rigidity of shell stringers/stringer spacing. Additional bending rigidity of shell frames/frame spacing. (Moments of in
22、ertia of stringers or frames to be computed about shell centerline) -21- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Card 13 14 - 15 16 Columns 1-5 6-20 21-35 36-50 51-65 66-80 6-20 21-35 6-20 21-35 Format A5 E15.0 E15.0 E15.0 E15.0 E15.0 E15.0 E
23、15.0 E15.0 E15.0 Description PLATE Floor structural data Ex(N/m2) Modulus of elasticity in the axial direction Ey (N/m2) Modulus of elasticity in the transverse direction vX Poissons ratio L, Poissonls ratio Y. Gxy (N/m2) Shear modulus. it is computed using G = E/2(l+v). If blank, Thickness of floor
24、 (m) Includes “smeared-out“ stiffener areas. Floor masdunit area (kg/m2) in- cluding “smeared-outt1 stiffener masses. D;= y long floor - (N.m) Additional bending rigidity of longi- tudinal floor beams/floor beam spacing. EX(t3-ti3) beam 12(1-v2) E (t3-ti3) D = y floor - Y (Nom) YP sumort 12(1-v2 1 A
25、dditional bending rigidity of trans- verse floor supports/support spacing. (Moments of inertia of stiffeners are to be computed about the floor center- line) -22- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Card - 17 18 19 20 21 22 23 24 25 26 27
26、 28 Columns 1-3 1-17 1-10 1-5 1-5 1-3 1-5 1-5 1-11 1-12 9-10 1-11 Format A3 A10,A7 A10 A5 A5 A3 A5 A5 All A12 I2 All Description END End of Input Data The following cards control the oper- ations performed by the program. GENERATE MATRICES CONSTRAINT SHELL PLATE END SOLVE PUNCH Outputs to Tape 7. (N
27、ot Card Punch) FREQUENCIES EIGENVECTORS 20 Number of eigenvectors (Generalized Coordinates) to be output (Maximum no. = 20, and Max.M x No. of eigenvectors 5 225) MODE SHAPES -23- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Card Columns Format De
28、scription 29 1-4 A4 TRAN Transverse mode shapes 38-40 I3 20 Number of mode shapes to be output 0 43-45 I3 36 Number of increments for shell. Displacements output at 5 degree intervals 48-50 I3 10 Number of increments for floor Displacements output at intervals of floor width Lp/20. 55 L1 T u and v d
29、isplacements calculated 60 L1 T output required on Tape 7. 30 1-3 A3 END 31 1-10 A10 END OF JOB 32 1 6/7/8/9 End of file. No library subroutines are required. The program MRP must be run twice, once for SYMMETRIC modes and once for ANTISYMMETRIC modes. The same data is used in both cases except for
30、Card 5. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-5.2.2 Output File, Tape 7 The two output files, Tape 7, one for symmetric and one for anti- symmetric modes, must both be cataloged or stored for input to program MRPMOD. These output files may
31、be large if axial mode orders M = 1 to 10 are all included and care should be taken to allow for this. For example, on the CDC NOS computing service, Tape 7 should be defined as a Direct Access File rather than an Indirect Access File which is limited in size. For each value of M in turn, the output
32、 file, Tape 7, contains information on the first 20 normal modes including Resonance frequencies Generalized coordinates Shell displacements Floor displacements 5.2.3 Printed Output Shell and Plate structural data. For each value of M in turn: Constraint matrices Eigenvalues and Resonance frequencie
33、s Generalized coordinates for first 20 modes Shell and floor displacements for first 20 modes Graphical representation of mode shapes. -25- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-5.3 Program MRPMOD 5.3.1 Input Data - Card Columns Format Desc
34、ription 1 1-80 16A5 Title card. This will be passed to program PAIN by Tape 9 output. 2 1-5 I5 No. of terms used for shell displacement series in program MRP Final ns + 13 6-10 I5 No. of terms used for floor displacement series in program MRP Final np + 11 3 1-5 I5 No. of values of M in program MRP.
35、 Maximum no. of longitudinal half- wavelengths. 4 1-5 I5 No. of terms used for shell dis- placement series in program PAIN Maximum = 53 6-10 I5 No. of terms used for floor displace- ment series in program PAIN Maximum = 31 For these, the most significant terms of the series will be selected by program MRPMOD 5 1-10 F10.0 Angle eo (degrees) at which the floor joint is located (eo = 0 at bottom centerline) -26- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
