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Full-Text Articles in Mechanical Engineering

Deep Learning Of Nonlinear Dynamical System, Aditya Wagh Jan 2020

Deep Learning Of Nonlinear Dynamical System, Aditya Wagh

Dissertations, Master's Theses and Master's Reports

A data-driven approach, such as neural networks, is an alternative to traditional parametric-model methods for nonlinear system identification. Recently, long Short- Term Memory (LSTM) neural networks have been studied to model nonlinear dynamical systems. However, many of these contributions are made considering that the input to the system is known or measurable, which often may not be the case. This thesis presents a method based on LSTM for output-only modeling, identification, and prediction of nonlinear systems. A numerical study is performed and discussed on Duffing systems with various cubic nonlinearity.


Structural Health Monitoring Of Composite Parts: A Review, Jacob Pessin Jun 2019

Structural Health Monitoring Of Composite Parts: A Review, Jacob Pessin

Honors Theses

Structural health monitoring has the potential to allow composite structures to be more reliable and safer, then by using more traditional damage assessment techniques. Structural health monitoring (SHM) utilizes individual sensor units that are placed throughout the load bearing sections of a structure and gather data that is used for stress analysis and damage detection. Statistical time based algorithms are used to analyze collected data and determine both damage size and probable location from within the structure. While traditional calculations and life span analysis can be done for structures made of isotropic materials such as steel or other metals, composites …


Monitoring Damage Initiation And Growth In Composite Structures By Acoustic Emission Method, Kassahun Mekonnen Asamene Jan 2013

Monitoring Damage Initiation And Growth In Composite Structures By Acoustic Emission Method, Kassahun Mekonnen Asamene

Dissertations

In this dissertation, acoustic emission technique is examined as candidate for monitoring the integrity of polymer matrix structural members. Acoustic emission technique has so far been largely limited to laboratory tests and field applications have been mostly limited to qualification tests of aerospace structures. The lack of quantitative indications of damage in composite structural members associated with the complex nature of damage in these materials has been a limiting factor. Generally, a number of failure modes operate simultaneously at a site of damage, and each of these failure modes generates a different type of acoustic emission signal. In addition, issues …


A Novel Ultrasonic Method To Quantify Bolt Tension, Jairo Andres Martinez Garcia Mar 2012

A Novel Ultrasonic Method To Quantify Bolt Tension, Jairo Andres Martinez Garcia

USF Tampa Graduate Theses and Dissertations

The threaded fasteners are one of the most versatile methods for assembly of structural components. For example, in bridges large bolts are used to fix base columns and small bolts are used to support access ladders. Naturally not all bolts are critical for the operation of the structure. Fasteners loaded with small forces and present in large quantities do not receive the same treatment as the critical bolts. Typical maintenance operations such tension measurements, internal stress checking or monitoring of crack development are not practical due to cost and time constrains. Although failure of a single non-critical fastener is not …