Attachment 007 - MATCE Input Datasheet Tracked Vehicle.xlsx

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UNCLASSIFIED

18 Oct 2024 for Tracked Vehicles

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(*Distribution Statement A only applies when form is not filled in)

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Narrative Vehicle Data Package for Next Gen Mobility Analysis

1.0 INTRODUCTION:

This package describes the parametric data requirements for high resolution Next Gen Mobility Analysis Tool (MAT) and vehicle dynamics analysis using methodologies such as CREATE-GV Mecury tool or other commercial tools such as MotionView, Recurdyn or ADAMS. The nature of these methodologies is such that detailed vehicle data are necessary to formulate the models for the simulation to be performed. In order to fascilitate high fidelity mobility analysis and dynamic models of modern vehicle systems, an attempt has been made here to provide generic data sheets to define the vehicle system parameters necessary to conduct any desired simulations. Special vehicle features or performance characteristics which are not covered by the data sheets need to be described and paramters provided in sufficient detail for high resolution dynamic simultions.

2.0 OBJECTIVES:

The purpose of this package is to: 1) define in detail the parameters, drawings, and descriptions that are necessary to perform high resolution mobility and vehicle dynamics analysis, 2) provide standardized work sheets which will fascilitate tracked vehicle system description and model development.

3.0 RECOMMENDATIONS:

It should be noted that the data defined in this package has a direct effect on the dynamic response of the vehicle. However, the parameter values are generally quite difficult to determine. As the model can only be as accurate as the data provided, consideration should be given to collecting accurate and precise data to be used in the modeling process. When accurate data are used correctly in a vehicle dynamic simulation, accurate results can be produced and decisions can be made based on predicted vehicle performance.

4.0 DATA SHEETS:

In order to assess mobility and dynamic response of military vehicles, parametric data that describes the main subsystems of the vehicle must be known. The following datasheets are included to capture that data:

1. Sprung Vehicle Data

2. Powertrain data

3. Mobility Data

4. Tracked Vehicle A. Track Data B. Suspension properties C. Suspension spring /damper/bump-stop data D. Vehicle geometry data/supplemental data

5. Trailer Data

4.1 Vehicle Mass and Inertia Properties

For the level of details required for most analysis, it is sufficient to treat the vehicle sprung mass (chassis) as a single rigid body. However, if the first few mode shapes are known, provide the output from the finite element eigenvalue analysis from ANSYS, MSC/NASTRAN, COSMIC/NASTRAN. This data can be incorporated into the dynamic model to provide additional accuracy. All spinning components of the wheel such as the wheel hub and tire assembly should be combined into one. If the axle is not composed of a single rigid body then its configuration should be depicted in additional drawings and the mass/inertia properties given for each major component. All center of gravity locations should be given relative to a point located on the ground below the center of the front axle.

4.2 Powertrain data

It's important to know the available torque at all axles for the complete range of speed starting at 0 speed to the maximum vehicle speed. Where necessary, please use the drawings to explain how the engine torque (or motor torque for any hybrid configurations) transforms to traction at each axle. If there are any control algorithms (traction control, driveline control, etc.) that govern the distribution of power across all axles under various conditions, that should be clearly explained with drawings, schematics, input/output channels, and logic details. All codes should be provided with sufficient details in order to accurately assess the vehicle performance. All other properties requested on this sheet are self-explanatory.

4.3 Mobility Data

Properties from this section are used in the Mobility Analysis Tool (MAT) of CREATE-GV to assess geospatial mobility analysis of the vehicle using CREATE-GV to compute %GO/NO-GO, V50 speeds, and Vehicle Cone Index across various regions of interest in the world. The outputs from MAT are same as traditional NATO Reference Mobility Modeling (NRMM) except that instead of Vehdyn, it now requires high fidelity simulation data for ride quality, shock quality, and obstacle override (previously OBSMOD). This is why it is critical that all sections of the datasheet are accurately populated to be able to assess both Mobility as well as Vehicle Dynamics performance. This section requires mainly max vehicle dimensions, minimum ground clearance, CG locations, and tracked vehicle data.

4.4A Track Data This sheet asks for data on the sprocket, idler, support rollers, track links, and overall track properties. The data is required to create the tracked vehicle model.

4.4B Track Suspension Data In order to include inertial effect of each component, it's important to have center of gravity, mass, and inertia information of each moving body connected via joints. Since these values are highly reference frame and origin dependent, please explicitly mention the reference frame used to report the moment of inertia. For simplicity, it is suggested to use component center of gravity as the origin, and the local reference frame (that may or may not align with the global reference frame). The center of gravity of each component must be provided with respect to a known point on the vehicle such as front axle center on the ground.

4.4C Suspension Spring Damper Data Because of the wide variety of suspension systems in existence today, it is difficult to be explicit when specifying data requirements for a given vehicle suspension. It is important to emphasize that suspension systems significantly affect vehicle dynamic performance while negotiating terrain and obstacles, so they must be adequately modeled. Detailed drawings defining all suspension kinematics, joint locations, and attachment points of springs, shocks, and bump stops must be provided. All dimensions should be relative to a well defined locaiton on the vehicle such as point on the ground located below the center of the front axle.

When providing suspension data for the vehicle it is important to cover the entire range of operation and include enough points to depict non-linearities in the suspension. This should include jounce and rebound characteristics as well. Tabulated data is required for force-deflection relationships, but including a plot of the data showing jouce, rebound, and static equilibrium is desired. For independent suspensions, it should be stated whether the suspension force-deflection data (or damper force - velocity data) is at the spring (or shock) or the wheel, and if at the wheel, what the motion ratio is between the two.

If any intelligent conrols are used to deliver spring, damper, or anti-roll forces, please include the Native code with the proper documentation. The documentation must include input and output channels and polarity, the control logic, and detailed instructions about how to best integrate with a multibody dynamics software. It is important to get the codes in the native form to be able to generate executables compatible with the govt. tools to be able to accurately assess vehicle dynamics performance.

4.4D Vehicle Geometry Data Additional data will be required to set-up an accurate model of the vehicle system. This section covers data that would come in the form of engineering drawings. In particular, any drawings that depict the steering kinematics of the vehicle and supplemental drawings of the suspension showing damper and spring attachment points, axle attachment points, axle attachments, and bump stop locaitons. There should also be top level drawings of the vehicle including the system center-of-gravity location and overall vehicle dimensions.

As technology advances in recent years, new control algorithms such as semi-active/active, MR dampers, etc. are sometimes incorporated into the vehicle system to improve ride and handling; it's important to capture that improvment in the analytical models to accurate assess the vehicle performance. Control algorithm are therefore required to link them to Army multi-body simulation codes.

4.5 Trailer Data

Please provide the trailer hitch locations on both towing and towed vehicles and any joint mechanism or algorithm to control the hitch location. Please populate all worksheets # 3-5 for the trailer only to accurately model trailer vehicle dynamics model.

1. Sprung Vehicle Data

SPRUNG MASS DATA (at Curb and GVW condition w/o turret and weapon)

Chassis mass (sprung mass, excluding turret, gun, and other bodies described below) lbf-sec2/in *

TURRET DATA

Turret mass lbf-sec2/in

Provide finite element model and analysis data for each body that should be considered a compliant structure.

JLTV

&8Distribution Statement A* - Approved for Public Release; distribution unlimited. (*Distribution Statement A only applies when form is not filled in)

2. Power Train Data Power Train Data

Property Comment

% Drive torque distribution to all axles (under various operating conditions)

Time to achieve 0 to 40 mph (under full throttle) on highway under operating load, seconds

Engine maximum power (hp)

Curve data of net engine torque (in-lbf) vs. speed (rpm)

Specify gear ratios and efficiencies of the power train

For tracked vehicles, reflected rotational inertia at sprocket (lbf-in-s2) Inertia (lbf-in-sec2) = Inertia (lbm-in2) / 386.088

Engine/Transmission mass (lbf-s2/in) Mass (lbf-sec2/in) = Mass (lbm) / 386.088

Engine/Transmission center-of-mass location (CG) Provide x,y,z coordinates (in); specify coordinate system

Engine/Transmission mount locations Provide x,y,z coordinates of each mount (in); specify coordinate system

Engine Torque (ft-lbf) verus Engine RPM and Throttle Opening (%) Torque versus RPM for full range of Percent Throttle Openings

JLTV

&8Distribution Statement A* - Approved for Public Release; distribution unlimited. (*Distribution Statement A only applies when form is not filled in)

Engine/Transmission Front Trunion Location

Left X Y Z Right X Y Z Engine/Transmission CG

X Y Z Engine/Transmission Rear Mount Location

X Y Z Engine/Transmission Rear Mount Stiffness

X Y Z lb./in * * *

Transmission Data

[lbf*in*sec^2]

3. Mobility Data Mobility Data

(0 = Not powered,

(0 = Unknown, 1 = gasoline or 4-stroke-cycle diesel,

3A. Track Data

&14CUI

&14CUI

3B. Track Suspension Data

Roadwheels are numbered from the idler (if present) to the sprocket

&14CUI

&14CUI

3C. Susp Spring-Damper Data

Negative is Rebound, Positive is Jounce

Roadwheel 1, 2, 3… 2 Nominal Spring Torque at design load: (lbf)

&16

CUI

&16CUI

Drawings

4D. Vehicle Geometry Data Vehicle Geometry Data

(1) Provide a table of (x,y,z location) in a clearly defined reference frame. Also, provide the dimensioned drawings showing position*, geometry, connectivity, and layout of the following:

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&8Distribution Statement A* - Approved for Public Release; distribution unlimited. (*Distribution Statement A only applies when form is not filled in)

5. Trailer Data

SPRUNG MASS DATA (at Curb and with payload)

Trailer mass (sprung mass, excluding any payload) lbf-sec2/in *

PAYLOAD DATA

Payload mass lbf-sec2/in

&8Distribution Statement A* - Approved for Public Release; distribution unlimited.

(*Distribution Statement A only applies when form is not filled in) image1.emf image2.emf image3.wmf