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Optimising Arc-Based Additive Manufacture Using Fracture Mechanics Approaches

Project Code: 34788

Start date and planned duration: January 2022, 36 months


  • Develop arc-based additive manufacturing (AM) processing methods to minimise induced residual stress in the deposit with the aid of numerical modelling and process monitoring.
  • Determine the types and distribution of residual stresses that occur within arc-based AM builds.
  • Determine the mechanical, fracture and fatigue properties for arc-based AM materials.
  • Determine the suitability of current structural integrity assessment methods for arc-based AM material.
  • Establish new methods of treating arc-based AM materials in structural integrity assessments.

Project Outline

Arc-based AM, also known as arc Directed Energy Deposition (DED), is gaining significant interest in various industries, as its high deposition rate renders it promising for large load-bearing structures. The structural integrity of such structures is of paramount importance especially in safety critical applications. Residual stress distribution, tensile, fracture and fatigue properties are key inputs into structural integrity assessments, but such properties for arc-based AM materials are not yet well understood. Furthermore, arc-based AM materials may have anisotropic properties, which may require different assessment methods and criteria. These have become the main barriers for the adoption and expansion of arc-based AM into industrial production and structural applications.

The concept is to develop an arc-based AM approach aiming to minimise residual stress through the use of numerical modelling and other digital/smart tools (eg welding cloud systems, vision cameras and laser scanners) to deposit large structural components for residual stress measurement and characterisation of tensile, fracture and fatigue properties.

The data generated from a fracture mechanics perspective will then be used to determine the suitability of current structural integrity assessment methods, which are based on several assumptions on conventional material. Where current methods have been demonstrated to be unsuitable, new assessment methods will be developed to account for the differences between the AM and conventional material (eg material property anisotropy). 

Industry Sectors

-      Aerospace

-      Power 

-      Oil & Gas

-      Construction and Engineering

Benefits to Industry

The knowledge and capabilities that the project aims to generate will enhance TWI and its Industrial Members’ understanding of the relationship between residual stresses and AM processing, thereby feeding into AM process improvements to achieve optimal properties for structural applications. It will contribute to the industrialisation of arc-based AM and accelerate the adoption of AM technologies into the members’ production. The concept can be adapted by other AM technologies and material processing processes, eg laser and electron beam AM, cold spray and multi-pass welding.

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