Determining Cargo-Handling Requirements

by Major Gregory H. Graves

Modeling and simulation help combat service support combat developers make sure that soldiers have the container- and materials-handling equipment they need to accomplish their missions.

    As the Army transitions from a supply-based logistics system to one that is distribution based, we must make sure that we continue to provide the organizations that perform distribution functions in the theater of operations with the equipment they need. Following the Gulf War, senior Army leaders identified key logistics issues that required attention; since then, they have made great strides in addressing them. One of those key issues is the importance of container- and materials-handling equipment (CMHE).

    Units that operate as nodes in the theater distribution network can be transportation, quartermaster, ordnance, medical logistics, or postal units. However, each unit must have the proper CMHE to receive, store, reconfigure, and issue cargo. Every unit does not perform all of those processes in every situation, but each should have the capability to do so.

    In recent years, the Army Combined Arms Support Command (CASCOM) at Fort Lee, Virginia, has been assessing the cargo-handling capabilities of logistics units and seeking to improve the way requirements for cargo-handling equipment are determined and documented. To that end, improved decision-support tools will be incorporated into the processes used to determine the CMHE required by current theater distribution doctrine.

    The improved method to ensure that each organization is equipped to perform its required distribution processes has three steps.

Step 1—Document the Unit Process

    To determine accurate CMHE requirements for an organization, it is necessary to know the unit's required throughput capacity. For current Army units, this requirement is taken from the unit's table of organization and equipment and is stated in either short tons per day or containers per day.

    To determine the type and quantity of CMHE needed, the processes required to move the cargo through the organization must be defined and documented. Several different proponents within the combat service support (CSS) combat developments community are involved in this effort. To establish a uniform standard for the CASCOM study, TeamFlow, a commercial process-mapping software package, was selected to document the processes within the units. The documented processes form the basis for the two steps remaining in the CMHE requirements determination process.

Step 2—Assess Unit Equipment Adequacy

    Over the past 3 years, CASCOM has focused on improving the analysis in this step. The major accomplishment was the development of the CMHE assessment tool (CAT). As its name suggests, the CAT is used to assess the adequacy of a unit's CMHE to achieve its required throughput capacity.

    The CAT is a Microsoft Excel-based spreadsheet tool developed during the CMHE study completed by CASCOM in April 2001. It has a Visual Basic for Applications interface for data input and output reporting. The final report for the CMHE study includes a summary of the intent of the current version of the CAT—

    The CMHE Assessment Tool (CAT version 2.0) was designed to standardize the calculation of minimal CMHE Requirements for Supply Support Activities, Ammunition Supply Operations, and Transportation Terminal Operations. The model provides the combat developer or planner with the means to quantify cargo-handling equipment requirements based on a specified support mission and the tasks and processes associated with a variety of inbound and outbound cargo platforms. This model determines the accumulated cycle time to complete a daily workload that provides the basis for minimum CMHE requirements.

    The basic equipment requirement calculation performed by the CAT is found in Technical Manual 38-400, Joint Service Manual for Storage and Materials Handling. It takes into account the amount of cargo to be moved during an operational day, the amount of cargo carried per trip by type of equipment, the average time to accomplish a complete equipment trip cycle, and the length of an operational day. This calculation determines the minimum required quantity of each type of CMHE for a unit's operation.

This future truck with an intelligent load-handling system is a component of the Smart Distribution System being developed by CASCOM and the Army Tank-automotive and Armaments Command Armaments Research, Development, and Engineering Center. This future truck with an intelligent load-handling system is a component of the Smart Distribution System being developed by CASCOM and the Army Tank-automotive and Armaments Command Armaments Research, Development, and Engineering Center.

    The value of the CAT is clear when the amount of cargo to be moved in a day is expressed in short tons or containers per day. This amount of cargo must be converted into numbers of lifts by various types of equipment. The CAT currently determines quantities for the 4,000-pound rough terrain forklift; the 6,000-pound variable-reach forklift; the 10,000-pound ATLAS (all-terrain lifter, Army system); the yard tractor; the palletized load system; the rough-terrain container handler; the 7.5-ton rough-terrain crane; and the 40-ton rough-terrain container crane.

    Based on the documentation of the unit's processes and input from unit proponent subject matter experts, input data are developed for the CAT. The CAT can assess units functioning as supply support activities, distribution terminals, or ammunition organizations. A module for each function presents the user with a site layout screen based on the doctrinal operations of the type of unit selected. The user enters distances in meters between activity areas on the site layout screen. On subsequent screens, the configuration of cargo when it enters the unit is specified by platform and quantity (in either short tons or containers). The configuration of cargo when it leaves the unit then is specified in the same manner. Finally, the user specifies the percentage of each type of platform that undergoes each type of transfer operation in the receipt, storage, or issue process. Current cargo platforms incorporated in the CAT are 20- and 40-foot containers, 463L aircraft pallets, palletized load system flatracks, container roll-in-roll-out platforms, and a variety of breakbulk cargo vehicles.

    Since container handlers and forklifts move platforms rather than pounds or tons, a common unit for the amount of cargo being moved is needed. The CAT converts tonnage to breakbulk pallets by using cargo density factors. The cargo density factors used in the CAT were derived by CASCOM from historical data on military cargo shipments. The breakbulk pallet provides a common basis for determining the tonnage (weight) and volume (cubic inches) that platforms will hold. This becomes particularly important if reconfiguring loads is part of the unit's mission.

    After the user enters a platform mix and combination of processes, the business rules programmed into the CAT select the proper type of CMHE for each lift required to move cargo platforms through the organization. The business rules are based on the capabilities of the various types of CMHE and the physical characteristics of the platforms being moved. Examples of business rules on CMHE are: A 4,000-pound forklift is required for efficient discharging of breakbulk pallets from 40-foot ISO (International Organization for Standardization) containers; a 10,000-pound forklift is needed to handle 463L air cargo pallets and ISU (internal airlift/helicopter-slingable-container unit) containers.

    Once the proper type of equipment is selected, the CAT determines the cycle time for the lift. After all data have been entered, the CAT adds all cycle times for each type of equipment to determine the total number of hours that each must operate every day to accomplish all required lifts. The total then is divided by the number of hours in the unit's operational day and rounded up to determine the required baseline quantity for that type of equipment.

    After displaying the initial assessment results, the CAT also allows analysis of mission, enemy, terrain and weather, troops, time, and civilian considerations (METT-TC) to determine the impact that degraded environmental conditions would have on equipment requirements. Variations in illumination, mud depth, and mission-oriented protective posture levels are all modeled in the CAT. A reduced operational readiness rate also can be selected for each type of CMHE in the organization.

    The current version of the CAT was developed as a prototype to illustrate the principle of converting throughput capacity statements to equipment operational requirements. Initially, the focus was on moving cargo through the distribution system to the consumer. Realistically, organizations may be required to retrograde cargo and empty platforms through the system as well. These functions will be incorporated into the next version of the CAT proposed for development at CASCOM.

    Most business rules and equipment characteristics are programmed into the underlying CAT logic and therefore are inaccessible to the user. The next version of the CAT will have defaults for business rules, equipment characteristics, and operational day length, but the user will have certain options to change these defaults to add flexibility to the tool. Additional work is underway to refine data used for equipment characteristics and unit processes.

Step 3—Simulate Unit Operations

    The final step in the assessment methodology is to model the unit's operational processes using Arena simulation software. The CAT calculates the minimum quantity of equipment required based solely on the time it takes to move cargo through the unit. Therefore, the possibility exists that complex interactions between various pieces of equipment during the handling processes may have effects for which the CAT cannot account. Simulation helps to account for these effects in units where process mapping shows equipment interactions to be particularly complex. Simulation also allows the introduction of uncertainty into loading and unloading times and movement distances to assess the robustness of the CAT recommendations. Here the primary concern is determining the number of containers or short tons that move through the organization in a day.

    The baseline equipment requirements provided by the CAT serve as an initial basis for a simulation of the unit's operations. Since the unit's cargo-handling processes have been documented already using TeamFlow, these processes are converted to models in Arena. Arena provides the capability to simulate the movement of hundreds of platforms through a unit without actually having to deploy the unit to a tactical setting. Not only does the simulation capture the time that is spent moving cargo with CMHE, it also captures the time that cargo sits on the ground or on a truck waiting to be moved. Military units must be able to operate in a variety of conditions, so simulation is a valuable tool. While the CAT is deterministic and therefore uses typical layout distances and representative values for movement rates and lifting times, simulation provides the realism of uncertainty in these areas.

    Once the unit is modeled, the output from the simulation is analyzed to determine if adjustments to the CAT output have to be made to attain the required throughput capacity. If adjustments are needed, additional simulations are run to make sure that the adjusted quantities meet the unit's mission requirements. These adjustments then can be used by combat developers to propose changes to the unit's equipment requirements.

    While military experience and judgment are key aspects of combat developments, solid analysis is crucial for determining and defending requirements. The process of documenting cargo-handling procedures, assessing equipment adequacy, and simulating unit operations allows CSS combat developers to make sure that soldiers have the equipment they need to accomplish their missions. This process also will help ensure that future organizations will be able to support the Army's transformation to a distribution-based logistics system.

    As proponents develop concepts for units to support the Objective Force, the tools used in the process will enable the combat developers to build models that not only determine what equipment the units need but also illustrate and help clarify the way the units should operate. For this purpose, simulation will be particularly helpful. Simulation models provide animated views of unit operations so the people who formulate the concept for the unit will be able to see if the unit is operating the way they envision. Based on experience gained through simulation modeling, unit concepts and designs can be adjusted, and the end result will be a smoother CSS transformation.  ALOG

    Major Gregory H. Graves is an operations research analyst in the Directorate of Combat Developments for Combat Service Support at the Army Combined Arms Support Command at Fort Lee, Virginia. He holds a B.S. degree in engineering management from the U.S. Military Academy and an M.S. degree in industrial engineering from Texas A&M University. He is a graduate of the Field Artillery Officer Basic Course, the Transportation Officer Advanced Course, and the Army Command and General Staff College.