MODELLING APPLICATIONS OF ADDITIVE MANUFACTURING IN DEFENCE SUPPORT SERVICES
This PhD focuses on the evaluation of Additive Manufacturing applications in the context of Defence Support Services. The PhD contributes to knowledge through development of a framework which is able to estimate the cost, time and benefits such as impact on availability of AM applications in different locations of a Defence Support Service system.
Ø To review available AM technologies and develop a selection algorithm to identify most suitable technology based on application
Ø To investigate current practices and define a System of Interest (SoI) of a Defence Support Service (DS2) using a system approach. This objective allows to define the boundaries, elements, links, sequences of a Defence Support Service.
Ø To develop a holistic Conceptual Framework to assess AM applications in Support Services. The framework defines the necessary phases required to perform the assessment.
Ø To develop a hybrid Decision Support System (DSS) to assess quantitatively the impact of AM applications in DS2 outlining estimate on cost, time and availability. The DSS is engineered for early stages technology acquisition programs.
The Decision Support System (DSS) is a software prototype engineered for “Research & Development” (R&D) units employed in early stages of “Capability Acquisition” (CA) programs. The targeted capability which is investigated for acquisition is defined as follow:
” the capability to additively manufacture critical-to-availability components next/close to the point of use only when they are required, to maximise Operational Availability and reduce cost and time of Defence Support Services (DS2)”.
The software tool includes four novel mathematical models on Selective Laser Melting (SLM), Wire+Arc Additive Manufacturing (WAAM), Fused Deposition Modelling (FDM) and on the Supply Chain of a DS2. The DSS performs accurate and detailed product and service cost estimation and can simulate current and next-generation practices where AM is delocalised in various stages of the support system (i.e. a DS2 provider, a vessel, a port and a forward base).
Figure 1 represents the simulation environment where the user can compare the current practices, where manufacturing occurs in the back-end of a DS2 and next generation practices where AM is delocalised in the front-end. The user needs to select the System Configurations of both current and next generation practices and the location of the AM system. Moreover, data on Mean Time Between Failures (MTBF), Administrative Delay Time (ADT) and Procurement Delay Time (PDT) must be defined. In case of the next generation solution, the PDT is eliminated and substitute with the Cycle Time of the AM system.
Figure 2 represents the mathematical model of Wire+Arc Additive Manufacturing (WAAM) which is largely considered the most promising solution for large structural components in the maritime context.
The user needs to input the product data, type of material (Aluminium, Titanium, Stainless Steel), deposition volume of both the model and substrate, the deposition area and the substrate thickness. Moreover, the Wire Feed Speed (WFS) and the wire diameter have been included as these are variable of the process which have major impact on performance data. The module allows to include the setup time and design time which in some situation may lead to high costs (i.e. in topology optimisation). Once the user fires the model, the results are displayed on the right side of the Graphical User Interface (GUI). These include a detailed Cost Breakdown Structure (CBS) with 7 cost elements and a set of performance data such as the cycle time, deposition rate and design time.
Publications:
Ø Designing a WAAM Based Manufacturing System for Defence Applications (Cirp Procedia)
Ø Defining Next-Generation Additive Manufacturing Applications for the MoD (Cirp Procedia)
Ø Additive manufacturing applications in Defence Support Services (Journal Paper)
Ø Modelling AM applications in Defence (Web Article)