Project: Effects of Design Parameters on Tensile and Fatigue Properties of Additive Manufactured Parts Fabricated Using Laser Powder Bed Fusion Process

Partner Lead

AUBURN UNIVERSITY

Challenge

Need for establishing specimen property-part performance relationships (need for developing appropriate standards for AM) to address geometry/size, time intervals, and build orientation 

Objective

Better understand the relationships between test coupon and part performance by conducting systematic experimental procedures and simulations focused on the effects of part size, geometry, and time interval.

Approach

To study specimen property–part performance relationships through thermal simulation and systematic mechanical testing of coupons machined from various sized blocks representing differing time interval, part size, and geometry, design of experiments include the following steps: 

  • Fabricate parts in vertical, horizontal, and diagonal (45° to the build plate) directions and conduct tensile and fatigue tests to study the effect of layer orientation on the monotonic tensile and fatigue behavior of AM metallic specimens governed by alignment of principal stresses, grain orientation, and lack of fusion defects with respect to the loading direction.

  • Fabricate square blocks of different sizes to introduce variation in thermal history. Machine tensile and fatigue specimens from the fabricated parts to understand the effect of time interval and part geometry on the tensile and fatigue behavior of AM metallic parts.

  • Perform thermal simulations for all the fabricated parts to better understand the variation in thermal history resulting from the part geometry, how to circumvent such changes in thermal history for part-to-component thermal history matching, and to explain the results obtained from the mechanical testing.

  • Propose ASTM standards to be followed to relate the mechanical properties under tensile and fatigue loading to the geometry of the fabricated parts.

Impact

Auburn University will investigate mechanical testing issues with metal additive manufacturing to better understand the relationships between the properties of test specimens and the performance of parts. This study will contribute to a standard that guides how to design specimens (i.e., test coupons) that are most representative of additively manufactured components.