Effect of Energy Density on the Mechanical Properties of 1.2709 Maraging Steel Produced by Laser Powder Bed Fusion.

The unusual combination of the fundamentally contradictory properties of high tensile strength and high fracture toughness found in maraging steel makes it well suited for safety-critical applications that require high strength-to-weight materials. In certain instances, additive manufacturing (AM) has produced materials that may be desirable for safety-critical applications where impact toughness is a key property, such as structural parts for the aerospace industry or armor plates for military applications. Understanding the influence of process parameters and defect structure on the properties of maraging steel parts produced via laser powder bed fusion (LPBF) is a fundamental step towards the broader use of AM technologies for more demanding applications. In this research, the impact energy of V-notched specimens made of 1.2709 maraging steel produced by LPBF was determined via Charpy impact testing. Specimens were produced using different processing parameter sets. By combining the process parameters with the porosity values of the parts, we demonstrate that an almost full prediction of the impact properties can be achieved, paving the way for significantly reducing the expenses of destructive testing.

Laboratory and Numerical Investigation of Pre-Tensioned Reinforced Concrete Railway Sleepers Combined with Plastic Fiber Reinforcement.

This research investigates the application of plastic fiber reinforcement in pre-tensioned reinforced concrete railway sleepers, conducting an in-depth examination in both experimental and computational aspects. Utilizing 3-point bending tests and the GOM ARAMIS system for Digital Image Correlation, this study meticulously evaluates the structural responses and crack development in conventional and plastic fiber-reinforced sleepers under varying bending moments. Complementing these tests, the investigation employs ABAQUS' advanced finite element modeling to enhance the analysis, ensuring precise calibration and validation of the numerical models. This dual approach comprehensively explains the mechanical behavior differences and stresses within the examined structures. The incorporation of plastic fibers not only demonstrates a significant improvement in mechanical strength and crack resistance but paves the way for advancements in railway sleeper technology. By shedding light on the enhanced durability and performance of reinforced concrete structures, this study makes a significant contribution to civil engineering materials science, highlighting the potential for innovative material applications in the construction industry.