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It is a modest step towardsunderstanding the behavior of tracked vehicles under variousloading conditions. It will be a good starting point in anysubsequent research in this area. For this reason, the variousresults and the approach utilized were presented chronologicallyto keep the reader continuously in touch with the changes inanalysis approach, which was necessary for achieving the finalresults.The rapid development in computer hardware and softwaretechnology make undertaking such a task possible, something noteven thought of a few years ago. Undoubtedly, this developmentwill allow TACOM Personnel to tap into new area of research,which will allow them to revolutionize their design and analysisprocess.I would like to take this opportunity to express my appreciationfor the confidence and support that Mr.
Art Adlam and John Korpihave shown which allow me to dedicate myself to thisinvestigative study. Also I would like to thank Dr. Ron Beckand Mr. Zoltan Janosi for allowing me to get hands-on trainingon DADS program. Also I would like to thank Mr. Ken Cerelli andBob Garcia for their cooptration in utilizing the Finite ElementCode (IRM) and Patran Software. Also I would like to thank Mr.John Weller for his support in utilizing DADS program in theDynamic Analysis area and providing access to mathematicalprogram (MATLAB) which was utilized in performing the necessarymathematical calculation with high accuracy and great speed.xvxvi1. Summary - In this study, the dynamic effects of terrain load,in termof stresses in Components Advanced Technology Test BedThe stresses in the chassis(CATTB) Chassis, was investigated.due to terrain load is in the range of 3,000 PSI, at which theChassis experience a vertical acceleration of 2 at its CG.
Toanticipate the maximum terrain effects, either a more drasticcustom-made terrain can be used (Fig. 97) instead of ABG4(utilized in Fig 96), or the traveling speed of the CATTB couldbe increased from the 30 mph. For simplicity, the maximumterrain effects can be assumed to be a factor of thoseexperienced by the chassis based on previous road tests.In anyevent, a follow-up stress analysis is required.Stresses due to firing load (375,000 lb) is maximum in theturret uop plate (70,000 PSI).In the trunnion, it is in therange of 40,000 PSI.Stresses in the hull is maximum when thegun is firing at 90 degrees, and it is in the range of 80,000PSI. To maximize these stresses, only two road wheels wereassumed to provide resistance against lateral movement. In realsituations, all road wheels resist lateral movement in a complexinteraction between the track and terrain.
To understand thisbehavior, a separate 3D DADS analysis is required.Thetransient dynamic effect of gun firing force could not beperformed due to software difficulties. However, the model andinput file are saved for further studies in this area.2.INTRODUCTIONThe continuous advancement in technology, the introduction ofthe solid modelers, and the supercomputer lead to the evolutionof the design process at TACOM.
The old design method "shave ittill it breaks" simply will not work due to the complexity ofautomotive structure and the forces affecting it, and because ofthe enormous amount of time required by such an approach. Inthe new evolved design, all parameters and their effects can bequantified, and better results can be achieved in a much shorterperiod of time. This can be accomplished by building acomputer model which will serve as an inexpensive and expendableprototype. The mass properties (weight, moments of inertia andC.G location) for this prototype can be calculated easily byusing the solid modeler capabilities. The forces acting on thisprototype can be evaluated by performing a dynamic analysisutilizing the Dynamic Analysis and Design Software (DADS)available on the supercomputer. The strength of each componentwill be assured by conducting a Comprehensive Finite ElementAnalysis for this prototype under various loading conditions,such as firing load terrain forces, vibration, airdrop or blast,and other destructive testing.
The new design will produce thebest and most efficient product within the shortest span oftime. In addition, it will provide understanding of theinteraction of the various design parameters, which will helpmake any subsequent design modifications to be done with speedand confidence. The purpose of this study is to apply thissystematic design approach to the design of the ComponentsAdvanced Technology Test Bed (CATTB).23.0 Discussion - The material. presented in this reportrepresents design stages for the Component Advanced TechnologyTest Bed (CATTB).
It is categorically divided into four stagesas follows:Solid ModelinggIn this stage, CATTB geometry for turret and hull isestablished, and their physical properties areevaluated.Static Finite Element Analysis:The configuration of the CATTB chassis was establishedto accommodate the new light weight gun. For this, acomplete static finite element analysis was performedto assure the adequacy of the CATTB Chassis strengthunder various loading conditions.Dynamic Analysis:In this stage, a CATTB dynamic model was built andanalyzed using DADS software. The forces andacceleration acting on the various components wereestablished.Dynamic Finite Element Stress Analysis:A detailed finite element analysis was performed tostudy the dynamic nature of terrain and firing forcesand the effects of vibration on CATTB structure.The assumptions made and the results obtained for these fourstages as presented in detail on the following pages.34,Results:The results of the four design stages are presented asfollows:4.1CATTB Solid Model4.1.1Turret Solid Model:The objective of creating a solid model for the CATTB turretis to study the effects of the new turret feature (trunnion, newgun mount and side-plate locations) on the characteristicbehavior of the CATTB turret.
Also, it was necessary todetermine the new turret mass properties for establishing therequirement for the hydraulic system necessary to power theturret. A solid model was created on the Intergraph CAD systemutilizing EMS software. This model was created from a series ofprimitive solids (cubes Tetrahedron .....
) because changingdimensions length, height, and width can be achieved quiteeasily by lifting the faces or edges of these primitive solids.turret geometry is shown in Fig (1 - 3), turret solid model isshown in Fig (4 - 8).4.1.2Evaluation of CATTB Turret Mass Properties:The powerful capabilities of the CAD system were utilized toevaluate CATTB mass properties. These properties, which includeweight, CG locations, and moments of inertias for the CATTBturret's various components, are shown in Appendix A. TotalCATTB turret weight and the location of is C.G were determinedmathematically as, shown =.i Table 1. CATTB mass properties atabout any point can be determined by transforming massproperties of the various components from their own CG to thatgiven point as shown in Table 2 & 3.Plate thickness for CATTB turret structure is shown in Fig(1) side-armor thickness is 40 inches in the front area andprojected through proper angles to both sides.
The density ofside armor used is 0.095 lb/in and is ba§ed on 550 lb/ftFor 52" armor, the density is 0.104 Wb/in and is based on 750lb/ft .Top-armoi thickness used is 4 inches, except over the L.W.120mm gun front area, where it is 2 inches. At the rear gunarea, no top armor is used. The density of the top armor is0.1215 lb/in3 and is based on 70 lbs. per square ft. for 4inches thick.Spall liner is used on the inside of the CATTB Turret crewarea.
At thickness of one inch, the density of the spa!! linerused is 0.04 lb/in and is based on weight of 5.7 lb. persquare ft.,I414;To convert mass 2 properties from lbs. - in2 to slug (lbs. - ft - sec ), the following multiplication factorwas uaed:ft2X32.-2 1-2X120.0002157 or 2.1514-1-310MULL Solid Model:CATTB solid model for the hull and suspension are shown inFig (9 - 11). The basic hu.ll structure, skirts, spansons,grills and suspension (idler, roadarms, roadwheels and finaldrive) were created as solids.
Whereas, the power pack, fueltank, autoloader, and various electrical control boxes were notmodeled as a solid, but primitive solids were used to representtheir Geometry.4.1.4HULL Mass Properties:The mass properties of the various hull components abouttheir own CG was calculated using EMS software and are shown indetail in Appendix B. The hull CG was found and hull massproperties about the axis, passing through its CG was obtainedby transforming mass properties of the various hull componentsto the hull CG location, as shown in Table 4.5Table 1 Weicdht and C.G Location for CA7TIM Turret CnponentsCOMPONENTWEIGHTGUN (1)10,000 -90.46,810 -67.80017.0 -913,04017.0 -461.71800171,700115,770SIDE ARMOR( 4 01") 15,770 -26.7(50")24,150 -29.5TOP ARMOR2,900 14.0+ 0.6- 0.50.318.0 -421,06018.4 -712,43042.040,600- 9 460-12,080870.0283,860444,360121,800SPALL LINER(IN)FIRST MOMENTS(lbs-in)18.00.326.022,500375.032,500BASKET830 - 2.60.7-32.5- 2,158581.0-26,975COM'DR CHAIR16018.4-25.0- 9.52,944- 4,000- 1,520GUN CHAIR18012.025.8-16.52,1604,644- 2,970GUN HATCH12012.014.338.31,4401,7164,596WEAPON ST86020.6-23.640.317,716-20,29634,658GEAR BOX570 -23.427.34.4-13,33815,5612,508AUTO LOADER1,250C.G LOCATION3,65090.6- 0.824.50330,690- 2,92089,425BASICSTRUCTURE13,56054.7- 0.721.0741,730- 9,490284,700TOP PLATE3,65047.10.437.4BOTTOM PLATE4,34056.4- 0.15.9VERTICAL PLATE 2,88518.7- 3.419.4101.0- 0.424.70- 1.50(Crew Area)VERTICAL PLATE 2,685(Bustle Area)BEARING2650GUN SHIELD210-48.50.216.70-ELECTRICAL BOXES900- 2.50.416.70-GPS & MTAS63029.5SIGNATURE SUPP750 -25.017.700010,185--398423512,250360-15,03039.0011,15018,585018.50- 18,750- 0.07- 0.1119,5019.40241,471- 49,900- 3,516- 6,136961,7201,122,22019.320.3-209,850-501,220-3,516-6,1361,017,6501,234,080024,57013,875SKINTOTAI40"ArItmr)49,415(1) (50"Aror)5 7 , 7 9 54.80- 0.86(2) 40" (Armr) 52,700 -4.0 -0.0550" (Armor) 61,000 -8.2-0.10(1)Provided by Gun Manufacturer(2) Calculated Using EMS6I'able 21 Aass Propertibs of 'CAMI' TurretCaiponent5 About Axis Passing Through Their C.G'sPOMP0NENTS.GN (1)I y (lb - in )I x (1b - i2)I z (lb - i)172,11630,965,70059,680,70017,704,90030,777,1001,611,10059,680,70046,325,90080,912,9003,914,8601,333,1801,180,0602,188,140456,150404,680771,670OCU4'D CRAR38,79040,2606,860GUN'R CHAIR9,77011,7507,460GUN'R HATCH7,3704,44011,590WEAPON STATION90,74085,660172,140GEAR BOX33,82026,98025,080AL/TIO[IC IADER2,124,5601,202,4403,032,340BASIC SIRUCffURE13,976,55020,823,64033,667,790TOPPLATE2,206,8207,791,3509,987,530BUT= PLATE3,542,4708,690,13011,997,000VERTICAL PLATE(Crew Area)VERTICAL PLATE(Bustle Area)BEARING4,174,5503,013,5406,607,1904,052,7101,328,6205,076,070158,365158,365316,33016,93010,88012,575360,405373,095661,74541,820287,635276,595238,87547,670286,540(2)SIDE ARM R(40")(50")TOP ARMORSPALL LINERBASIETGUN SHIELDELECTICAL BOXESGPS & MIASSIGNATURE SUPP SKIN490,88031,060,20053,873,4001,731j330730,965,300Table 3 Mass Properties of CATTB Components AboutAxis Passing Through Its Center of RotationI y (lb - in')I z (lb - in )2,133,5003,409,78064,252,400145,138,42062,290,000142,219,52036,220,70062,060,7006,854,60034,089,70059,950,1007,315,60057,560,700101,912,0004,496,440SPALL LINER2,187,4002,438,8002,592,830BASKET1,340,0001,293,900777,900COM'DR CHAIR152,300103,960165,890GUN CHAIR183,93089,486157,880GUN HATCH245,560191,03096,7801,978,8001,856,8001,025,18066,78057,81544,2404,320,00033,417,00033,056,00021,989,34079,068,73083,967,8807,314,15020,999,40018,089,10022,633,30025,789,8005,297,4305,116,8307,653,4805,684,88030,319,20032,435,500158,365158,365316,33074,510553,560497,690611,180629,115667,250GPS & MTAS1,541c7301,436,1301,021,740SIGNATURE SUPP SKIN2,189,625516,4252,706,05082,248,320227,468,816251,440,780(50" Armor) 108.088;320253;329;216295;792;080I x (lb - in%)COMPONENTGUN(1)(2)SIDE ARMOR (40")(50")TOP ARMORWEAPON STATIONGEAR BOXAUTOMATIC LOADERBASIC STRUCTURETOP PLATEBOTTOM PLATEVERTICAL PLATES(Crew Area)VERTICAL PLATE(Bustle Area)BEARINGGUN SHIELDELECTRICAL BOXESTOTAL (40" Armor)(lb - in).3,692,880TOTAL (40" Armor) (I)(Slug - ft1 ) (50" Armor)17,74123,31549,06554,64354,23663,802TAL (40" Armor) (2)SLUG-FT 2 (50" Armor)18,01323,58666,52672,10371,46581,0308Mcment of Inertia of CATIB Turret About AxisPassing Through its C.G+Z)MI y-(x + z)Mzz-(x +y)Mx-I x=II yI zo =(yWhere I x, I y, and I z are moment of inertia about turret rotational center(table 4).
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