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Full-Text Articles in Engineering

Effect Of Manufacturing-Induced Defects And Orientation On The Failure And Fracture Mechanism Of 3d Printed Structures, Amit Khatri Dec 2016

Effect Of Manufacturing-Induced Defects And Orientation On The Failure And Fracture Mechanism Of 3d Printed Structures, Amit Khatri

Mechanical and Aerospace Engineering Theses

Additive manufacturing is a rapidly growing cutting edge technology. Number of experimental studies have shown that strength of product manufactured by additive Fused Deposition Method (FDM) is influenced by different processing parameters involved during manufacturing. This thesis work presents experimental and theoretical investigation of mechanical behavior of ABS material fabricated with variation in some of process parameters such as Axis Orientations, Raster Orientation, Infill Percentage, Layer Height and Number of Shells. Different experiments were designed to understand the basics of 3D printing manufacturing and to characterize the mechanical behavior of 3D printed structures. This study helps to understand, how different …


Slicing Algorithm For Complex Contour Generation From Coarse Meshed Iso-Surface Data, Divya Hareshkumar Shukla Dec 2016

Slicing Algorithm For Complex Contour Generation From Coarse Meshed Iso-Surface Data, Divya Hareshkumar Shukla

Mechanical and Aerospace Engineering Theses

Finite element based topology optimization is used to develop complex geometric configurations for additive manufacturing. Complex coarse-meshed Iso-surface data is extracted from topology optimization results and smooth mathematical geometry must be fit to that data in order to accomplish further design development. To accomplish this geometry fitting, cross-section data must be extracted at specific locations. The stereo lithography (STL) file format is a triangular mesh format which can be developed using 3D CAD Software and is widely used for additive layer manufacturing processes. The main aim of this research work is to generate cross-section contours using a nearest tail-to-head distance …


Development Of The Compact Jet Engine Simulator From Concept To Useful Test Rig, Henry H. Haskin Jul 2016

Development Of The Compact Jet Engine Simulator From Concept To Useful Test Rig, Henry H. Haskin

Mechanical & Aerospace Engineering Theses & Dissertations

Two Compact Jet Engine Simulator (CJES) units were designed for integrated wind tunnel acoustic experiments involving a Hybrid Wing Body (HWB) vehicle. To meet the 5.8% scale of the HWB model, Ultra Compact Combustor technology from the Air Force Research Laboratory was used. The CJES units were built and integrated with a control system in the NASA Langley Low Speed Aero acoustic Wind Tunnel. The combustor liners, plug—vane and flow conditioner components were built in-house at Langley Research Center. The operation of the CJES units was mapped and fixes found for combustor instability tones and rig flow noise. The original …


Investigation Of Additive Manufacturing Using Industrial Robots, Matt Heuser May 2016

Investigation Of Additive Manufacturing Using Industrial Robots, Matt Heuser

Mechanical and Aerospace Engineering Theses

Conventional additive manufacturing platforms are controlled using G-code, a numerical control language used to define the process parameters and move- ment of the print head. First, a digital model of the desired shape is created using 3-D computer graphics software. Then the model is analyzed by software tools that generate the necessary G-code instructions to be used by a 3-D printer to produce the desired object. The goal of this research is to lay the foundation and develop the necessary tools to 3-D print custom objects based on the viscous extrusion process using industrial robots. The first task is to …


Effects Of Additive Manufacturing Methods On The Dynamic Properties Of 15-5ph Stainless Steel, Allison A. Dempsey Mar 2016

Effects Of Additive Manufacturing Methods On The Dynamic Properties Of 15-5ph Stainless Steel, Allison A. Dempsey

Theses and Dissertations

Experimental research was conducted to determine the dynamic properties and characterize the microstructure of 15-5PH Stainless Steel manufactured through Direct Metal Laser Sintering (DMLS) additive manufacturing (AM) processes and heat treated using common heat treatment protocols. A thorough understanding of the material's properties is necessary before such parts are utilized in an operational capacity. Of the five builds, two deviated significantly from the specified composition of 15-5PH stainless steel. The remaining three builds, possessing the desired composition and crystalline structure, were tested in compression and tension at two strain rates. Tension tests using a reflected wave and a momentum trap …


Surface Roughness Of Electron Beam Melting Ti-6al-4v Effect On Ultrasonic Testing, Evan T. Hanks Mar 2016

Surface Roughness Of Electron Beam Melting Ti-6al-4v Effect On Ultrasonic Testing, Evan T. Hanks

Theses and Dissertations

Experimental research was conducted on the effects of surface roughness on ultrasonic non-destructive testing of Electron Beam Melted (EBM) additively manufactured Ti-6Al-4V. Additive Manufacturing (AM) is a developing technology with many potential benefits, but certain challenges posed by its use require further research before AM parts are viable for widespread use in the aviation industry. Possible applications of this new technology include, Aircraft Battle Damage Repair (ABDR), small batch manufacturing to fill supply gaps, and replacement for obsolete parts. The research presented here assesses the effectiveness of ultrasonic inspection in detecting manufactured flaws in EBM manufactured Ti-6Al-4V. EBM products are …


Design Optimization Of Sandwich Core, Mohammad Tauhiduzzaman Jan 2016

Design Optimization Of Sandwich Core, Mohammad Tauhiduzzaman

Open Access Theses & Dissertations

Ultralight sandwich structures comprising of low-density core with stiff facings have attracted significant research interest for their considerable weight saving applications. The aircraft industries are focusing on decreasing the structural mass to lower the manufacturing and operating costs. Design analysis of the sandwich cores using finite element analysis has been developed as a promising concept to feature sandwich structures with maximum strength, stiffness, and reduced weight. To obtain multifunctional behavior of sandwich panels, a profound investigation of geometrical and mechanical properties in the transverse plane is required because it is very susceptible to any kind loadings. Structural optimization is one …