Original Date: 04/07/1997
Revision Date: 04/14/2003
Information : Lightweight Howitzer New Product Development
Using Integrated Product/Process Development for a Lightweight Howitzer Technology Demonstrator, Rock Island Arsenal (RIA) developed a fully operational prototype in fifteen months. RIA prides itself on making use of innovative technologies to satisfy challenging technological problems. Military users said they wanted more for less and faster. The technology demonstrator illustrates RIA’s commitment and showcases the capabilities of the Arsenal to design and develop using state-of-the-art techniques.
New weapons systems typically take eight to ten years from the requirements phase to first production release. The user would establish a material needs statement which documented the mission requirements. These were based on experience with currently fielded systems as well as projecting the need for future mission capabilities. Designers would take the requirements and begin the process of developing concepts to meet these needs, fabricate a prototype to evaluate the concepts, make design changes to address any shortcomings, re-evaluate the changes on the prototype, and fabricate a second or third generation prototype before finally releasing it for production. Today, military users expect a quicker turnaround time and lower cost. This has demanded a new approach for doing business. Eliminating the traditional iterative approach to design and test requires using Integrated Product Teams, or concurrent engineering.
RIA used Integrated Product Teams, or concurrent engineering, in 1994 when a conceptual model for a lightweight 155mm towed howitzer was developed to address the needs of the user as specified in the Joint Operations Requirement Document. These requirements defined such things as weight, envelope, traverse and elevation requirements, emplacement and displacement times, and rates of fire. The concept conceived by the Arsenal focused on the technology of soft recoil to reduce weight, improve durability, and reduce cost. This concept was briefed to users at Fort Sill, engineers at the Armament Research Development and Engineering Command (ARDEC) and the newly-formed LW155 PM office. The potential benefits from this approach showed enough promise that ARDEC provided limited funding for RIA to design and fabricate a technology demonstrator which would incorporate the soft recoil features. With this limited funding in hand, the Arsenal set out to develop a fully operational howitzer in less than eighteen months.
Because of the restricted budget and compressed schedule, the Arsenal immediately formed an Integrated Product and Process Team consisting of solids modelers, structural and dynamic modelers, process planners, quality specialists, contract specialists, and metallurgists. These team members worked as a unit to develop the design. State of the art CAD solids modeling was used exclusively in the creation of the components and structures. Each component was evaluated by means of finite element analysis to ensure that structural soundness and minimal weight had been maintained. The operational performance of the weapon was simulated through computer modeling to ensure acceptable performance. Before each part was released for fabrication, an extensive producibility assessment was made and designs were changed as needed to ensure the lowest cost solutions were being used. These concurrent engineering activities verified design integrity with finite element analysis; evaluated operational performance with dynamic modeling; assessed weight and Center of Gravity from solids model derivation; and validated shop floor machining processes all before the first chip was cut. In other words, a virtual prototype had been created from which functional and performance evaluations were made, and procurement and fabrication costs assessed. When the actual prototype was constructed, conventional testing was used to confirm the operational performance and structural integrity predicted by the virtual prototype model.
The concurrent engineering approach used on the technology demonstrator prototype saved more than $1M in design costs and shortened the development cycle by more than half when compared to the historical approach (15 months vs. 36 months), and the weight reduction was 44%. There were additional benefits that could have been realized if the program continued, including elimination of a second or third prototype, since all structural and performance evaluations were conducted during computer modeling and confirmed during limited testing. The previously acceptable costs normally expended during the Producibility, Engineering, and Planning Phase would be eliminated, since producibility was designed into the first prototype, and the prototype was built using actual production processes that would be employed in production.
Lessons learned from this experience make the Arsenal an experienced government agency in concurrent engineering techniques. People of different disciplines can work together in a team environment and make a significant difference in the outcome of a project. The computer aided tools used in virtual prototyping significantly help in arriving at the best and lowest cost solutions in the shortest time.
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