! TITLE: seal.mac (HSTA) ! !----------------------------------------------------------------------- ! Rev - 10/12/2005 D. Edwards !----------------------------------------------------------------------- ! ! Simrit rotary seal analysis at cold temperature located between ! the no-back oil cavity and the greased gearbox. ! ! Simrit darwing number: 10 0242 43922 00 Rev A ! ! This analysis performs an inital load step to deform the seal from ! its free state to its installed state. The load step consists of ! 13 substeps in Ansys 9.0. ! ! The second load step takes the seal down from room temp (75 deg F) ! -65 deg F. ! ! Consider the tangential and radial effects as the seal shrinks ! at cold temperature. As the seal contracts, the length of the ! circumference decreases. Without the aluminum reinforcement, this ! effect would be equivalent to installing a shorter rubber band ! onto the shaft which would result in a higher contact pressure ! between the seal and the shaft (increasing friction at cold). ! However, with the aluminum reinforcement constraining the seal ! to a near constant circumference, the effect of stretching ! a smaller rubber band on to a constant diameter, results in ! a thinner section. Thus the aluminum reinforcement causes ! the tangential component of the shrinkage to reduce friction. ! In the radial direction, the elastomer shrinks to thin the gap ! between the aluminum piece and the shaft. ! ! The elastomer get harder at cold temperature, which probably ! gives it a lower coefficient of friction. ! ! The elastomer most likely get stiffer at cold temperature. ! This would be the one effect which tends to increase friction. ! If temperature data becomes available, it would be worthwhile ! to determine the magnitude of this effect. ! ! In conclusion, it appears that in contradiction to initial ! intuition, the friction decreases at cold, rather than increase. ! ! ! Addition refinements that could be added: ! ! 1. Model surrounding gland to determine if there is a leak ! path aound the outer sufaces of the seal. ! 2. Add Mooney-Rivlen data at various temperatures across the ! temperature range. ! 3. The garter spring was not modeled becasue it is not ! relavent to the goal of this analysis, which was to examine ! the final state of the more directly under the end of the "L" ! shaped aluminum piece nearest the shaft. ! 4. Run the model with minimum material conditions as the worst ! case for leakage at cold. ! 5. The Mooney-Rivlen model was taken from an Ansys example ! which was based on an unknown elastomer. The correct model ! for fluorosilicon rubber should be used. ! ! ! CS_0: Cartesian seal Coordinate System ! CS_1: Cylindrical seal Coordinate System ! CS_2: Spherical seal Coordinate System ! ! !************************** TABLE OF CONTENTS ************************** ! ! Model Assembly Preparation ! ! 1. Parameter List ! 2. Model Coordinate System ! 3. Solid Model and Meshing ! 4. Solution ! !********************* Model Assembly Preparation ********************** ! mod_assemb_prep,arg1,arg2,arg3 ! prepare database for assembly ! !<<<<<<<<<<<<<<<<<<<< 1. Parameter List >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ! seal.parm ! !<<<<<<<<<<<<<<<<<<<< 2. Model Coordinate System >>>>>>>>>>>>>>>>>>>>>>> ! mod_coord_system,acs,xc,yc,zc,rotxyc,rotyzc,rotzxc ! !<<<<<<<<<<<<<<<<<<<< 3. Solid Model >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ! ! ! Keypoint Definitions from seal.parm ! k,km+1,x1,y1,z1 ! km + 1 k,km+2,x2,y2,z2 ! km + 2 k,km+3,x3,y3,z3 ! km + 3 k,km+4,x4,y4,z4 ! km + 4 (center) k,km+5,x5,y5,z5 ! km + 5 k,km+6,x6,y6,z6 ! km + 6 k,km+7,x7,y7,z7 ! km + 7 (center) k,km+8,x8,y8,z8 ! km + 8 k,km+9,x9,y9,z9 ! km + 9 k,km+10,x10,y10,z10 ! km + 10 (center) k,km+11,x11,y11,z11 ! km + 11 k,km+12,x12,y12,z12 ! km + 12 k,km+13,x13,y13,z13 ! km + 13 (center) k,km+14,x14,y14,z14 ! km + 14 k,km+15,x15,y15,z15 ! km + 15 k,km+16,x16,y16,z16 ! km + 16 (center) k,km+17,x17,y17,z17 ! km + 17 k,km+18,x18,y18,z18 ! km + 18 k,km+19,x19,y19,z19 ! km + 19 k,km+20,x20,y20,z20 ! km + 20 k,km+21,x21,y21,z21 ! km + 21 (center) k,km+22,x22,y22,z22 ! km + 22 k,km+23,x23,y23,z23 ! km + 23 k,km+24,x24,y24,z24 ! km + 24 (center) k,km+25,x25,y25,z25 ! km + 25 k,km+26,x26,y26,z26 ! km + 26 k,km+27,x27,y27,z27 ! km + 27 (center) k,km+28,x28,y28,z28 ! km + 28 k,km+29,x29,y29,z29 ! km + 29 k,km+30,x30,y30,z30 ! km + 30 (center) k,km+31,x31,y31,z31 ! km + 31 k,km+32,x32,y32,z32 ! km + 32 (center) k,km+33,x33,y33,z33 ! km + 33 k,km+34,x34,y34,z34 ! km + 34 k,km+35,x35,y35,z35 ! km + 35 k,km+36,x36,y36,z36 ! km + 36 k,km+37,x37,y37,z37 ! km + 37 k,km+38,x38,y38,z38 ! km + 38 k,km+39,x39,y39,z39 ! km + 39 k,km+40,x40,y40,z40 ! km + 40 k,km+41,x41,y41,z41 ! km + 41 (center) k,km+42,x42,y42,z42 ! km + 42 k,km+43,x43,y43,z43 ! km + 43 k,km+44,x44,y44,z44 ! km + 44 k,km+45,x45,y45,z45 ! km + 45 k,km+46,x46,y46,z46 ! km + 46 (center) k,km+47,x47,y47,z47 ! km + 47 k,km+48,x48,y48,z48 ! km + 48 (center) k,km+49,x49,y49,z49 ! km + 49 k,km+50,x50,y50,z50 ! km + 50 k,km+51,x51,y51,z51 ! km + 51 k,km+52,x52,y52,z52 ! km + 52 k,km+53,x53,y53,z53 ! km + 53 (center) k,km+54,x54,y54,z54 ! km + 54 k,km+55,x55,y55,z55 ! km + 55 k,km+56,x56,y56,z56 ! km + 56 k,km+57,x57,y57,z57 ! km + 57 k,km+58,x58,y58,z58 ! km + 58 k,km+59,x59,y59,z59 ! km + 59 k,km+60,x60,y60,z60 ! km + 60 (center) k,km+61,x61,y61,z61 ! km + 61 k,km+62,x62,y62,z62 ! km + 62 k,km+63,x63,y63,z63 ! km + 63 k,km+64,x64,y64,z64 ! km + 64 k,km+65,x65,y65,z65 ! km + 65 k,km+66,x66,y66,z66 ! km + 66 k,km+67,x67,y67,z67 ! km + 67 k,km+68,x68,y68,z68 ! km + 68 k,km+69,x69,y69,z69 ! km + 69 k,km+70,x70,y70,z70 ! km + 70 k,km+71,x71,y71,z71 ! km + 71 k,km+72,x72,y72,z72 ! km + 72 k,km+73,x73,y73,z73 ! km + 73 k,km+74,x74,y74,z74 ! km + 74 k,km+75,x75,y75,z75 ! km + 75 (center) k,km+76,x76,y76,z76 ! km + 76 (center) k,km+77,x77,y77,z77 ! km + 77 (center) k,km+78,x78,y78,z78 ! km + 78 (center) ! ! Line Definitions ! L,km+1,km+2 ! lm + 1 larc,km+1,km+3,km+4,r1 ! lm + 2 larc,km+5,km+6,km+7,r2 ! lm + 3 larc,km+8,km+9,km+10,r3 ! lm + 4 larc,km+11,km+12,km+13,r4 ! lm + 5 larc,km+14,km+15,km+16,r5 ! lm + 6 L,km+17,km+18 ! lm + 7 larc,km+19,km+20,km+21,r6 ! lm + 8 larc,km+22,km+23,km+24,r7 ! lm + 9 larc,km+25,km+26,km+27,r8 ! lm + 10 larc,km+28,km+29,km+30,r9 ! lm + 11 larc,km+31,km+2,km+32,r10 ! lm + 12 L,km+33,km+34 ! lm + 13 L,km+8,km+11 ! lm + 14 L,km+35,km+36 ! lm + 15 L,km+29,km+26 ! lm + 16 larc,km+14,km+12,km+41,r11 ! lm + 17 L,km+35,km+43 ! lm + 18 larc,km+44,km+36,km+46,r12 ! lm + 19 larc,km+44,km+9,km+48,r13 ! lm + 20 L,km+49,km+6 ! lm + 21 larc,km+51,km+49,km+53,r14 ! lm + 22 L,km+54,km+51 ! lm + 23 L,km+56,km+57 ! lm + 24 larc,km+57,km+59,km+60,r15 ! lm + 25 L,km+61,km+59 ! lm + 26 L,km+63,km+61 ! lm + 27 L,km+63,km+64 ! lm + 28 L,km+65,km+64 ! lm + 29 L,km+17,km+65 ! lm + 30 L,km+18,km+67 ! lm + 31 L,km+68,km+43 ! lm + 32 L,km+69,km+5 ! lm + 33 L,km+33,km+22 ! lm + 34 L,km+69,km+19 ! lm + 35 L,km+15,km+25 ! lm + 36 L,km+28,km+31 ! lm + 37 L,km+23,km+71 ! lm + 38 L,km+72,km+71 ! lm + 39 L,km+72,km+3 ! lm + 40 larc,km+73,km+74,km+75,r16 ! lm + 41 larc,km+73,km+56,km+76,r17 ! lm + 42 larc,km+54,km+74,km+77,r18 ! lm + 43 L,km+20,km+72 ! lm + 44 L,km+34,km+69 ! lm + 45 larc,km+68,km+67,km+78,r19 ! lm + 46 ! Turn on KP and line numbers & switch to front view. /pnum,kp,1 /pnum,line,1 /view,1,,,1 /ang, 1 /rep,fast lplot ! ! Definition area and meshes ! ! ! --- Aluminum Angle Brace Area and Mesh --------------------------------- ! lsel,s,loc,x,x33,x23 lsel,r,loc,y,y33,y34 lsel,a,loc,x,x19,x71 lsel,r,loc,y,y33,y71 cm,alum_lines,line al,all !MSH_ALGORITHM, perflsz, perfmsh, mstyp, mshdens, elmszovr, atargov, etpa, ! etpv, elmnl, elmxl, mtrl, rl, ecs, volsel, radrot, ! (8) (9) (10) (11) (12) (13) (14) (15) ! varcang, ell ! (16) (17) msh_algorithm,1,1,0,0,,,alum,,0.005,0.005,alum eplot ! ! --- Rubber Area and Mesh ----------------------------------------------- ! alls lsel,s,loc,x,x5,x72 lsel,r,loc,y,y69,y72 lsel,inve cm,rubber_lines,line asel,none al,all msh_algorithm,1,1,0,0,,,rub,,0.005,0.005,rub eplot ! ! Define Boundaries ! ! Define the ballscrew shaft boundary ! and mesh it with one element k,,x63,-.03 k,,x63,y61+.03 init_entity_num lstr,km-1,km init_entity_num lesize,lm,,,1 type,2 real,1 mat,5 lmesh,lm ! ! Size and surface mesh seal surfaces that can contact the shaft ! ksel,s,kp,,63,65 ksel,a,kp,,17 lslk,s,0 nsll,s,1 type,3 esurf alls ! ! Mesh the upper left KP of the fixed boundary ! type,2 real,1 mat,4 kmesh,km ! ! Constrain part vertically at one point ! dk,19,uy,0 ! ! Get the node number at the upper left fixed boundary ! *set,n_load,node(kx(km),ky(km),0) fini ! !<<<<<<<<<<<<<<<<<<<< 4. Solution >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ! ! ! Seal Installation Load Step ! /solu nlgeom,on ! Non-linear geometry - large defl/strain support solc,on ! Soulution Control time,Dbs/2-x63 ! Used to keep track abs. displacement d,n_load,ux,Dbs/2-x63 ! Displace upper rigid boundary down nsubst,40,200,10 ! 25 = # of substeps on 1st step. ! 200 = max substeps for solution ! 10 = min substeps in solution outres,all,all monitor,var3,n_load,fy ! MONITOR,VAR,Node,Lab: 3rd field in monitor is FY solve save,seal_inst ! ! Cold Temperature Load Step ! tref,75 tunif,-65 solve fini ! Vector sum of displacements /post1 /eface,1 avprin,0,0, plnsol,u,sum,2,1