Browsing by Subject "fatigue life"

Now showing 1 - 6 of 6

Effect of Powder Degradation on the Fatigue Behavior of Additively Manufactured As-Built Ti-6Al-4V
(University of Texas at Austin, 2018) Carrion, Patricio E.; Soltani-Tehrani, Arash; Thompson, Scott M.; Shamsaei, Nima
Additive manufacturing (AM) technology has enabled many industries to generate functional parts with an increased level of complexity via a layer-by-layer melting. In laser-powder bed fusion (L-PBF), the most commonly used AM process for metals, powder is often recycled due to its high cost. However, there is no comprehensive study on how recycling powder affects its rheological properties, and the mechanical and fatigue behavior of the final manufactured part. In this study, a comparison of new and used Ti-6Al-4V powder characteristics was made. The comparison includes morphology, size distribution, as well as monotonic tensile and fatigue behavior of fabricated specimens. Conclusions and suggestions on powder recycling are made. Results indicate that the powder particle size distribution (PSD) becomes narrower and the morphology of the particles change with recycling. However, no comparable effect was observed on the monotonic tensile and fatigue behavior of the AM as-built Ti-6Al-4V specimens.
Effect of Voronoi Lattice Geometry on the Fatigue Performance of Ti-6Al-4V
(University of Texas at Austin, 2021) Uí Mhurchadha, S.M.; Marques, S.; Givet, L.; Raghavendra, R.
This paper investigates the effect of strut thickness and number of pores on the fatigue performance of Ti-6Al-4V voronoi lattice structures designed with the same part volume. The aim of this study is to establish the variation in high cycle fatigue parameters for constant volume lattice structures designed with various lattice parameters. Voronoi geometries were designed with varying strut thicknesses and number of pores to maintain a constant specimen volume. The geometries were tested under compressive fatigue conditions at a reversal ratio, R, of 0.1. It was found that the strut thickness has a significant influence on the fatigue life of the lattice. An increase in the strut thickness by 100 µm can result in a reduction in fatigue life by up to a factor of 10. The results from this research can influence the design of lattice structures for osteointegration in loadbearing biomedical implant applications.
Fatigue Analysis in Selective Laser Melting: Review and Investigation of Thin-Walled Actuator Housings
(University of Texas at Austin, 2014) Stoffregen, Hanns A.; Butterweck, Katja; Abele, Eberhard
The versatile applicable selective laser melting (SLM) is a promising manufacturing technology that allows 3-dimensional design freedom for complex and challenging load bearing parts. A specific application of SLM is the production of thin-walled housings for piezoceramic actuators which induce cyclic loads. Although there are investigations on the fatigue behavior of SLM-specimens, wide acceptance of SLM is limited by a lack of knowledge concerning the operating behavior of actual parts. This paper presents a review on existing studies about fatigue life analysis in SLM as well as results from uniaxial high cycle fatigue (HCF) tests of 1.4542 stainless steel as-built and machined specimens with a stress ratio of R = 0. Due to a lower surface roughness machined specimens show significantly higher fatigue strength compared to as-built ones. The obtained fatigue strength at 107 cycles of as-built specimens is used as input for fatigue tests of thin-walled actuator housings. Numerical simulation is used to determine the stress distribution of thin-walled as-built actuator housings under specific loads. Results indicate that the thin-walled as-built actuator housing withstand higher peak stresses compared to as-built specimens due to a high stress gradient.
Fatigue Behavior of Additive Manufactured Parts in Different Process Chains - An Experimental Study
(University of Texas at Austin, 2017) Uhlmann, Eckart; Gerlitzky, Georg; Fleck, Claudia
Metal based Additive Manufacturing (AM) has experienced dynamic growth in recent years. However, the global distribution of Additive Manufacturing is limited by the fact the produced parts suffer from bad surface quality and the material properties concerning fatigue life are still an object of current investigations which limits possible applications of AM parts. Due to this fact metal AM processes are often followed by a post process to ensure a better surface quality. In this paper the authors present results where fatigue life and different post processes of additive manufactured parts are investigated. Subsequently, surface roughness, high cycle fatigue, fracture behavior and microstructure have been characterized. Finally the results for the different post processing states have been compared and surface properties as well as microstructure have been correlated with the fatigue properties in order to evaluate how different process chains influence the High cycle fatigue (HCF) behavior of additive manufactured parts.
Fatigue Life Prediction of Functionally Graded TPU and PLA Components Produced by Material Extrusion
(University of Texas at Austin, 2023) Alkunte, Suhas; Rajeshirke, Mithila; Huseynov, Orkhan; Fidan, Ismail
The objective of the present research is to examine the fatigue life estimation of functionally graded additive manufacturing (FGAM) components produced by the Material Extrusion (MEX). Current research studies demonstrate the potential of functionally graded materials (FGMs) in enhancing the mechanical properties of engineered structures. The raw materials employed for the experimentation of this study are a combination of Polylactic acid (PLA) and Thermoplastic Polyurethane (TPU). To predict fatigue life, several researchers have utilized various statistical approaches. In this investigation, an experimental study is conducted utilizing Tension-Tension (T-T) loading conditions and different stress levels (80, 60, 40, and 20% of Ultimate tensile strength), followed by the application of Basquin’s Model for fatigue life prediction. The results obtained indicate that the model may be utilized to predict fatigue response. Overall, the soft-hard material combinations with adaptable properties produced through FGAM have potential applications in dental and orthopedic fields.
Investigating the Impact of Functionally Graded Materials on Fatigue Life of Material Jetted Specimens
(University of Texas at Austin, 2017) Kaweesa, Dorcas V.; Spillane, Daniel R.; Meisel, Nicholas A.
The capability of Additive Manufacturing (AM) to manufacture multi-materials allows the fabrication of complex and multifunctional parts with varying mechanical properties. Multi-material AM involves the fabrication of 3D printed objects with multiple heterogeneous material compositions. The material jetting AM process specifically has the capability to manufacture multi-material structures with both rigid and flexible material properties. Existing research has investigated the fatigue properties of 3D printed multi-material specimens and shows that there is a weakness at the multi-material interface. This paper seeks to investigate the effects of gradual material transitions on the fatigue life of 3D printed multi-material specimens, given a constant volume of flexible material. In order to examine the fatigue life at the multi-material interface, discrete digital-material gradient steps are compared against the true functional gradients created through voxel-level design. Results demonstrate the negative effects of material gradient transitions on fatigue life as well as the qualitative material properties of true versus discrete gradients.