Fatigue Analysis of Short Carbon Fiber Reinforced Composite Components Manufactured Using Fiber-Reinforced Additive Manufacturing

Fiber-reinforced additive manufacturing (FRAM) has become quite popular in several industries. The technology offers an opportunity to improve the existing mechanical performance of the part. This research study has presented a successful methodology to fabricate the FRAM- based composite parts with improved fatigue properties. Most engineering applications are subjected to cycling loading which makes the fatigue study an important analysis. The scope of this paper is to present the fatigue properties of short carbon fiber-reinforced Polyethylene Terephthalate Glycol (SCFs/PETG) of 13.78% by weight. The fatigue behavior was analyzed by varying the 3D printing process parameters i.e., infill orientation (0°, 45°, and 90°), and infill layer heights (0.2 and 0.3 mm). The tests are carried out on 1600 N as a maximum load of fatigue cycle with a 0.1 stress ratio, for the specimens with 90° and 45° orientations with 0.2 and 0.3 mm layer heights. For 0° orientation, both 0.2 and 0.3 mm layer height specimens are applied to 2600 N as maximum load, keeping the stress ratio the same as 0.1. Analysis of Variance (ANOVA) is used to statistically analyze the testing data to understand the influence of input variables on fatigue properties.Mechanical Engineerin

The influence of shielding gas configurations on formability of the ferritic stainless steel laser weld

Abstract According to previous studies the careful argon shielding of the weld is very important in order to achieve a ductile and formable laser weld of Ti-stabilized ferritic stainless steel. In practice it is often difficult to use the root gas shielding of the laser weld. The aim of this study was to determine the sufficient practise of gas shielding in order to achieve the ductile laser weld. According to Erichsen formability results the shielding gas nozzle in the post weld side must be used in order to reach the good formability of the laser weld. The single shielding gas pipe before the weld is not a sufficient method for the gas shielding. There is no need to use root gas in order to achieve a ductile weld. The single shielding gas pipe before the weld can cause a uptake blast in the key hole and further oxidize the weld metal

The normal and shear strength properties of laser lap weld

Abstract The study was aimed to clarify the shear strength and the normal strength properties of the lap joint. The welds were characterized with respect to hardness, tensile and fatigue properties. The test materials of this study were low strength carbon steel (LSS) and ultra high strength wear resistant steel (UHSS). The shear strength, perpendicular strength and fatigue resistance of the lap joint laser weld was determined by tensile and fatigue tests. The shear strength of the LSS weld was higher than the strength of the base material. The shear strength of UHSS weld was higher than the LSS weld. However, compared to strength of the base material of the UHSS the weld was weaker even though the weld was harder than the base material. The normal strength of the UHSS and LSS welds was over two times higher than the shear strength of the same welds

Disk laser assisted surface heat treatments of AlSi10Mg parts produced by selective laser melting (SLM)

Abstract Metal parts produced with the Selective Laser Melting (SLM) method have a great variety of uses today and because of this the requirements on the surface quality differ between applications. The surface treatments of the printed metal pieces, like other finishing phases, are often still manually worked on and thus are very time-consuming processes. This study focuses on the SLM printed AlSi10Mg aluminium specimen’s surface laser heat treatment with disk laser equipment (wavelength of 1030nm). The goal of this study was to achieve the desired effect on the aluminium’s surface quality with robotized laser heat treatment equipment. This was to show that the used finishing treatment method could be automated or robotized. The study showed that with the correct laser parameters, it is possible to generate desired effects and features on to the AlSi10Mg aluminium piece’s surface with a robotized process

Mechanical Properties of Laser Heat Treated 6 mm Thick UHSS‐Steel

In this work abrasion resistant (AR) steel with a sheet thickness of 6 mm was heat treated by a 4 kW Nd:YAG and a 4 kW Yb:Yag–laser, followed by self‐quenching. In the delivered condition, test material blank (B27S) is water quenched from 920° C. In this condition, fully martensitic microstructure provides excellent hardness of over 500 HB. The test material is referred to AR500 from now onwards. Laser heat treatment was carried out only on top surface of the AR500 sheet: the achieved maximum temperature in the cross‐section varies as a function of the depth. Consequently, the microstructure and mechanical properties differ between the surfaces and the centre of the cross‐section (layered microstructure). For better understanding, all layers were tested in tensile tests. For a wide heat treatment track, the laser beam was moved by scanning. Temperatures were measured using thermographic camera and thermocouples. Laser heat treated AR500 samples were tested in hardness tests and by air bending using a press brake machine. Microstructures were studied using a light microscope and FE‐SEM∕SEM‐EBSD. At least three kind of microstructure layers were observed: 1) Dual‐Phase ferritic∕martensitic (T  =  AC1–AC3), 2) ferritic (T ∼ AC3) and 3) bainitic∕martensitic (T>AC3)