Engineering Commons^™

A Novel Approach For Real-Time Quality Monitoring In Machining Of Aerospace Alloy Through Acoustic Emission Signal Transformation For Dnn, David Adeniji, Kyle Oligee, Julius Schoop

Mechanical Engineering Faculty Publications

Gamma titanium aluminide (γ-TiAl) is considered a high-performance, low-density replacement for nickel-based superalloys in the aerospace industry due to its high specific strength, which is retained at temperatures above 800 °C. However, low damage tolerance, i.e., brittle material behavior with a propensity to rapid crack propagation, has limited the application of γ-TiAl. Any cracks introduced during manufacturing would dramatically lower the useful (fatigue) life of γ-TiAl components, making the workpiece surface’s quality from finish machining a critical component to product quality and performance. To address this issue and enable more widespread use of γ-TiAl, this research aims to develop a …

A Novel Approach For Real-Time Quality Monitoring In Machining Of Aerospace Alloy Through Acoustic Emission Signal Transformation For Dnn, David Adeniji, Kyle Oligee, Julius Schoop

Mechanical Engineering Faculty Publications

Gamma titanium aluminide (γ-TiAl) is considered a high-performance, low-density replacement for nickel-based superalloys in the aerospace industry due to its high specific strength, which is retained at temperatures above 800◦C. However, low damage tolerance, i.e., brittle material behavior with a propensity to rapid crack propagation, has limited the application of γ-TiAl. Any cracks introduced during manufacturing would dramatically lower the useful (fatigue) life of γ-TiAl components, making the workpiece surface’s quality from finish machining a critical component to product quality and performance. To address this issue and enable more widespread use of γ-TiAl, this research aims to develop a real-time …

Characterization And Modeling Of Surface Roughness And Burr Formation In Slot Milling Of Polycarbonate, David Adeniji, Julius M. Schoop, Shehan Gunawardena, Craig Hanson, Muhammad Jahan

Mechanical Engineering Faculty Publications

Thermoplastic materials hold great promise for next-generation engineered and sustainable plastics and composites. However, due to their thermoplastic nature and viscoplastic material response, it is difficult to predict the properties of surfaces generated by machining. This is especially problematic in micro-channel machining, where burr formation and excessive surface roughness lead to poor component-surface integrity. This study attempts to model the influence of size effects, which occur due to the finite sharpness of any cutting tool, on surface finish and burr formation during micro-milling of an important thermoplastic material, polycarbonate. Experimental results show that the depth of cut does not affect …

The Effect Of Cutting Edge Geometry, Nose Radius And Feed On Surface Integrity In Finish Turning Of Ti-6al4v, Ian S. Brown, Julius M. Schoop

Mechanical Engineering Faculty Publications

While the respective effects of nose radius, feed and cutting edge geometry on surface integrity have each been studied at depth, coupling between these effects is not yet sufficiently understood. Recent studies have clearly established that cutting edge micro-geometries may not only have positive effects on tool-life, but can also be used to tailor surface integrity characteristics, such as surface roughness and near-surface severe plastic deformation. To further a more fundamental understanding of the effects of cutting edge micro-geometries on surface integrity, experimental turning data was generated for a varied range of cutting tool geometries and feeds. Scanning laser interferometry …

Computationally Efficient, Multi-Domain Hybrid Modeling Of Surface Integrity In Machining And Related Thermomechanical Finishing Processes, Julius M. Schoop, David Adeniji, Ian S. Brown

Mechanical Engineering Faculty Publications

In order to enable more widespread implementation of sophisticated process modeling, a novel, rapidly deployable multi-physics hybrid model of surface integrity in finishing operations is proposed. Rather than modeling detailed chip formation mechanics, as is common in numerical models, the proposed models integrates existing analytical and semi-empirical models of the plastic, elastic, thermal and thermodynamic domains. Using this approach, highly complex surface integrity phenomena such as residual stresses, grain size, phase composition, microhardness profile, etc. can be accurately predicted in a manner of seconds. It is envisioned that this highly efficient modeling scheme will drive new innovations in surface engineering.

Analysis Of Surface Integrity In Machining Of Cfrp Under Different Cooling Conditions, Arjun Nagaraj

Theses and Dissertations--Mechanical Engineering

Carbon Fiber Reinforced Polymers (CFRP) are a class of advanced materials widely used in versatile applications including aerospace and automotive industries due to their exceptional physical and mechanical properties. Owing to the heterogenous nature of the composites, it is often a challenging task to machine them unlike metals. Drilling in particular, the most commonly used process for component assembly is critical especially in the aerospace sector which demands parts of highest quality and surface integrity.

Conventionally, all composites are machined under dry conditions. While there are drawbacks related to dry drilling, for example, poor surface roughness, there is a need …

Engineered Surface Properties Of Porous Tungsten From Cryogenic Machining, Julius M. Schoop

Theses and Dissertations--Chemical and Materials Engineering

Porous tungsten is used to manufacture dispenser cathodes due to it refractory properties. Surface porosity is critical to functional performance of dispenser cathodes because it allows for an impregnated ceramic compound to migrate to the emitting surface, lowering its work function. Likewise, surface roughness is important because it is necessary to ensure uniform wetting of the molten impregnate during high temperature service. Current industry practice to achieve surface roughness and surface porosity requirements involves the use of a plastic infiltrant during machining. After machining, the infiltrant is baked and the cathode pellet is impregnated. In this context, cryogenic machining is …

Process-Induced Surface Integrity In Machining Of Niti Shape Memory Alloys, Yusuf Kaynak

Theses and Dissertations--Mechanical Engineering

NiTi alloys have been the focus of Shape Memory Alloys (SMA) research and applications due their excellent ductility and shape memory properties, and these alloys have been extensively used in automotive, aerospace, and in biomedical applications.

The effects of machining on the surface integrity and the corresponding material and mechanical properties of alloys can be best studied by utilizing NiTi alloys as workpiece material since their physical and mechanical properties are highly microstructure dependent. However, due to very poor machining performance of NiTi shape memory alloys, no comprehensive or systematic investigation on this topic has been conducted by researchers as …