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Full-Text Articles in Mechanical Engineering

Dynamic Testing: An Experimental Approach To Defect Identification In Additive Manufactured Parts, Aimee Allen Jan 2020

Dynamic Testing: An Experimental Approach To Defect Identification In Additive Manufactured Parts, Aimee Allen

Dissertations, Master's Theses and Master's Reports

Today’s additive manufacturing (AM) industry produces specialized parts at low volume or with complex geometries. Traditional testing methods are effective, but costly and time consuming to perform. The AM industry lacks an optimized testing method for identifying internal defects that occur in parts. The evaluation of multiple parts printed on the same build plate for internal defects using various nondestructive (dynamic) testing techniques is presented. From these experiments, perspective was gained on when and how dynamic testing can be used to find defects. Insight gained from these experiments can help the industry in future testing for internal defects.


3d Printing Of Iron Oxide Incorporated Polydimethylsiloxane Soft Magnetic Actuator, Rasoul Bayaniahangar Jan 2020

3d Printing Of Iron Oxide Incorporated Polydimethylsiloxane Soft Magnetic Actuator, Rasoul Bayaniahangar

Dissertations, Master's Theses and Master's Reports

Soft actuators have grown to be a topic of great scientific interest recently. As the fabrication of soft actuators with conventional microfabrication methods are tedious, expensive, and time consuming, employment of 3-D printing fabrication methods appears promising as they can simplify fabrication and reduce the production cost. Complex structures can be fabricated with 3-D printing such as helical coils can achieve actuation performances that otherwise would not be possible with simpler geometries. In this thesis development of soft magnetic helical coil actuators of iron-oxide embedded polydimethylsiloxane (PDMS) was achieved with embedded 3-D printing techniques. Composites with three different weight ratios …


Heterogeneous Uncertainty Quantification For Reliability-Based Design Optimization, Mingyang Li Jan 2020

Heterogeneous Uncertainty Quantification For Reliability-Based Design Optimization, Mingyang Li

Dissertations, Master's Theses and Master's Reports

Uncertainty is inherent to real-world engineering systems, and reliability analysis aims at quantitatively measuring the probability that engineering systems successfully perform the intended functionalities under various sources of uncertainties. In this dissertation, heterogeneous uncertainties including input variation, data uncertainty, simulation model uncertainty, and time-dependent uncertainty have been taken into account in reliability analysis and reliability-based design optimization (RBDO). The input variation inherently exists in practical engineering system and can be characterized by statistical modeling methods. Data uncertainty occurs when surrogate models are constructed to replace the simulations or experiments based on a set of training data, while simulation model uncertainty …