Ramin Amid, Ryerson University

Date of Award

2003

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

First Advisor

Zouheir Fawaz

Second Advisor

Kamran Behdinan

Abstract

Many studies were directed toward understanding damage patterns in composite laminates and determining the damage development sequence upon high velocity impact. Damage accumulation depends on projectile velocity and on a number of other parameters, so that it is not possible to set strict limits between the different regimes. 

However, experiments show that, for a given set of experimental conditions where the impact speed is the only variable, there is a certain threshold velocity below which no detectable damage occurs. Above the threshold velocity, no surface damage is observed except for a small indentation at the contact point, but significant internal damage consisting of delaminating and matrix cracks is introduced. As the impact velocity increases further, surface damage due mainly to fiber breakage is introduced. For very high speeds, the target does not have time to deform, and perforation occurs, leaving a clean hole in the sample.

The objective of this study is to develop a mathematical model that corresponds to the deformed geometry under high velocity impact applications for composite laminates. A total of 100 tests were conducted on composite laminates, struck by cylindrohemispherical projectiles at normal incidents with velocities up to about 100 mls. The types of materials, used this study, are AS4/3051, IM7/5250 CarbonlEpoxy and TI003

Glass/Epoxy. The strain energy was obtained by derivation of the proposed deflection function. The strain energy was plotted with respect to the deflection of the mid-plane and, then correlated through dynamic correlation factors to actual kinetic energy during the impact. The dynamic correlation factors were determined using a genetic algorithm regression analysis. Two types of materials were tested, namely plain graphite composites and hybrid composites. The growth of the delamination and also the effect of varying the stacking sequence were investigated for the different type of materials and various orientations. 

The mathematical model appears to provide a reasonable representation of the deformation of composite laminates during the penetration by a cylindro-hemispherical projectile. Furthermore, hybrid composites appear to provide more resistance to the impact, whereas plain composites have less resistance with respect to the higher velocities. It was concluded that, the change of the material in a hybrid composite affects the growth of the damaged area and also reduces the impact penetration resistance. Hence, IM7/E-Glass hybrid has a higher resistance to the penetration. Measurements of

the energy levels of the hybrid composites indicated that they offer the highest resistance to ballistic perforation. The hybrid composites perforated at velocities between 77 mls and 83 (mls), whereas the graphite composites perforated at velocities between 48 m/s and 59 (mls). The higher perforation resistance is attributed to the reduced level of delamination generated during the impact, and also the addition of the E-Glass, which was capable of absorbing more energy during the impact.

In studying the graphite composites, the best orientation in terms of the stacking sequence was found to be [(45, -45, 0, 90) 2 ] S , which indicates that this stacking sequence withstand higher velocity and hence absorbs more energy during the impact. Therefore, the quasi-isotropi corientation [(45, -45, 0, 90) 2 ] S is best for impact resistance if a laminate is not combined with E-Glass. The ballistic-limit velocity prior to perforation for the Quasi-isotropic laminate was measured as 58.9 m/s. This is a significant increase compared to the other plain graphite samples. The energy required for the complete perforation is approximately 48% higher in this stacking sequence as compared to other plain Graphite specimens. It was also found that the energy absorption capability is reduced significantly in the cross-ply laminates. The penetration resistance of the [(0,90,0,90) 2 ] S laminate and the energy required for perforation are approximately 50% less than the other plain graphite specimens.

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Muhammad Adrees, Ryerson University

Date of Award

2003

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

First Advisor

Filippo. A. Salustri

Abstract

In this thesis the author discusses the Design Structure Matrix (DSM) as a best practice. The DSM provides project management structure, develop and modularises the systems level design of products, performs project scheduling, tasks interdependency, resource allocation, dependent tasks planning, and provides proper communication and coordination structure.

The DSM tool is applied to two case studies of the design of a gasoline/electric hybrid vehicle power train and one case study of assembly design, with concentrated emphasis on the recommendations on how the specific cases in this thesis can benefit. A novel analytic feature Relative Significance Summation Clustering (RSSC) of the DSM is also identified, which appears to be otherwise unreported in the literature.

The case studies analysis demonstrates that the DSM tool can be used to develop a deeper understanding of the system level design, project management, and assembly design.

The DSM tool was successful at providing a representation of many of the issues and insights identified in the case study analysis.

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Qiang (John) Sun, Ryerson University

Date of Award

2004

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

First Advisor

Fengfeng Xi

Abstract

This thesis presents a newly developed system for simulation and control of reconfigurable machines and applications in the polishing process. A software package is developed that consists of the Varying Topology Simulation and Control System (VT-Sim) as well as the Polishing CAM (P-CAM) software system.

VT-Sim can simulate and control reconfigurable machines of serial or tree structures. It is developed based on mechatronic modules, each of which has a graphic user interface that can be connected to a physical module. The selected modules are linked through a graph-based topology design platform to generate an assembled system together with the equations for simulation and control.

P-CAM can simulate and generate CNC codes for the polishing process. The roughness of the polished parts is simulated for selected polishing parameters. Once satisfied, polishing tool paths can be generated and visualized.

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Peter Krimbalis, Ryerson University

Date of Award

2004

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

Abstract

Six embalmed cadaver heads were obtained, prepared and subsequently impacted to the medial maxilla with a 142-gram baseball traveling at 14 m/s. Measurements of strain were obtained through the use of strain gauge rosettes located at the medial palate and both canine fossae. Three dimensional finite element models of a dentate human maxilla were constructed for the purpose of investigating the mechanical response to a simulated blunt impact. Convergence testing revealed that a refined mesh with over 70,000 degrees of freedom was necessary to obtain sufficient accuracy within the analysis. The simulated load case involved a transient, dynamic impact to the medial maxilla with boundary conditions imposed at the buccal segments of the model analogous to the experimental case. Results were validated by a direct comparison to the displacements and principal strains gathered from experimental and epidemiological data. 

For the examined load case, displacements were highly localized at the anterior portion of the maxillary incisors. The comparison of experimental and calculated principal strains as a result of the simulated impacts revealed a 1.67 to 11.37% difference in magnitude.

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Nelson Da Silva, Ryerson University

Date of Award

2004

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

Abstract

This thesis involves the use of simulation models to evaluate and optimize existing manufacturing assembly lines of electrical components. The goal of the simulation is primarily to mimic the existing production scenario in order to identify problematic areas such as bottleneck operations, conveyor speeds limiting production and factors inhibiting the performance of the resources. This simulation project uses a combination of the AweSim ® software and logic programming using MS Visual Basic ® . 

Through coding, the logic of the flow of the parts is demonstrated in the course of the steps such as the intermittent conveyors with single and double part flow. There are line selection rules in the models that follow restrictions which will affect the makespan, mean flow time and the utilization of the resources. Using different scenarios conclusions and recommendations are made on modifications to the existing production in order to improve makespan and mean flow time.

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Yijing Cai, Ryerson University

Date of Award

2004

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

First Advisor

Liping Fang

Abstract

An automated machining process planning system for rotational parts is designed, developed and implemented. The system is called IPPS_R for Intelligent Process Planning System for Rotational parts. The IPPS_R system is designed for generating process plans for manufacturing rotational parts using metal cutting operations. A generative approach is employed to determine process operations and sequences automatically. For each machining feature, based on the accuracy and surface quality requirements, a fuzzy logic approach is developed to generate machining operations. A method of ranking the machining priorities of the features according to the feature relationship matrix is developed for sequencing operations. Moreover,

 the heuristic search of process plans is achieved by minimizing the number of setups in a plan. Finally, the IPPS_R system with a user-friendly interface is implemented in Microsoft Visual C++ on a personal computer, utilizing Microsoft Foundation Class (MFC). Two sample parts are used to demonstrate applications of the IPPS_R system.

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Sacheen Bekah, Ryerson University

Date of Award

2004

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

Abstract

This thesis presents the use of Finite Element (FE) based fatigue analysis to locate the critical point of crack initiation and predict life in a door hinge system that is subjected to both uni-axial and multi-axial loading. The results are experimentally validated. The FE model is further used to obtain an optimum design per the standard requirement in the ground vehicle industry. The accuracy of the results showed that FE based fatigue analysis can be successfully employed to reduce costly and time-consuming experiments in the preliminary design stage. 

Numerical analysis also provides the product design engineers with substantial savings, enabling the testing of fewer prototypes.

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Marc David Alexander, Ryerson University

Date of Award

2004

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

First Advisor

Kamran Behdinan

Abstract

This thesis describes a flight test evaluation of flight control laws applying rotor state measurements and feedback on the National Research Council Bell 412 Advanced Systems Research Aircraft (ASRA) and Bell 205A Airborne Simulator (AS).

Parameter estimation of a higher-order mathematical model of the ASRA rotor dynamics was achieved by Maximum Likelihood Estimation (MLE) employing coupled rotor-body equations parameterized by explicit rotor and fuselage state measurements.

Root Locus (RLM), Classical Multivariable (CMC), Eigenstructure Assignment (EAC), and Model Following control algorithms were implemented in Matlab/Simulink simulation for analysis of coupled rotor-body dynamics.

Rotorcraft performance specifications were based on compliance with ADS-33E-PRF and Cooper Harper military handling qualities.

Evaluated in desk-top and in-flight simulation, rotor state feedback of longitudinal and lateral disc tilt dynamics by modern multivariable control significantly improves inter-axis decoupling, disturbance rejection characteristics, rotor response dynamics, command tracking accuracy, and rigid-body bandwidth performance.

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Behzad Yousefirad, Ryerson University

Date of Award

2005

Degree Type

Thesis Project

Degree Name

Master of Engineering (MEng)

Department

Mechanical Engineering

First Advisor

Hekmat Alighanbari

Abstract

When wing root attachments are subject to cyclic loading during a flight, slipbands are produced by fatique. The density of these slipbands increases with the advancing of the fatigue process and initial cracks appear within the persistent slipbands. This project investigates the fatigue response of a titanium alloy wing root joint under different loading spectra during limit-cycle oscillations by the strain-life approach. Although wing root attachments are designed such that the nominal loads remain elastic, stress concentrations often cause plastic strains to develop in the vincinity of notches. Subsequently, wing loads caused by limit-cycle oscillations lead to fatique damage accumulation.

 This project's results lead to the conclusion that cyclic loading during limit-cycle oscillations can cause fatigue damage in wing root joints. Tensile mean stress is detrimental to the fatique life of wing root joints, while compressive mean stress is beneficial.

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Yi Yang, Ryerson University

Date of Award

2005

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

First Advisor

Ahmad Ghasempoor

Second Advisor

Jeff Xi

Abstract

Grinding is one of the important machining processes when tight tolerances and fine surface finishes are required. However, due to the large number of process parameters involved, predicting the outcome of a grinding process is not a trivial task. This thesis describes the development of a predictive model of surface finish in the fine surface grinding process. The surface topography of a grinding wheel was analyzed using a laser scanner. The statistical distribution for grain protrusion heights and the transverse and longitudinal spacing of grains were determined. Each protruded grain is counted as a cutting edge that engages with the workpiece to generate a unique chip. 

A solid modeller was used to model an individual chip as an ellopsoid. The measured topography of the grinding wheel, together with a kinematic relationship in surface grinding, was used to determine the geometrical characteristics of the ellipsoid. The solid modeller was then used to model the chip removal process by successive grains. The surface roughness predicted by the model was compared with experimental results. The results showed good consistency between the model and the actual surface properties.

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Yong Xia, Ryerson University

Date of Award

2005

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

First Advisor

Ahmad Ghasempoor

Abstract

Vibration control strategies strive to reduce the effect of harmful vibrations on machinery and people. In general, these strategies are classified as passive or active. While passive vibration control techniques are generally less complex, there is a limit to their effectiveness. Active vibration control strategies, on the other hand, require more complex algorithms but can be very effective. In this current work, a novel active vibration control experimental system, including the hardware setup and software development environment, has been successfully implemented. 

A static artificial neural network-based active vibration control system has been designed and tested based on the experimental system. The artificial neural network is trained to model the plant using a backpropagation algorithm. After training, the network model is used as part of a feedforward controller. the efficiency of this controller is shown through experimental tests.

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Hao Wu, Ryerson University

Date of Award

2005

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

First Advisor

Jun Cao

Abstract

In proton-exchange membrane fuel cells, it is particularly important to maintain appropriate water content and temperature in the electrolyte membrane. Taking into account the diffusion of water, the pressure variation, and the electro-osmotic drag in the membrane and using an empirical relationship between electro-osmotic drag and water content, a transport equation for membrane water molar concentration was obtained, and a new equation for the electric potential that strictly accounts for variable water contents was derived. The new potential equation is more accurate than the conventionally employed Laplace's equation.

 A number of numerical simulations are performed for comparing the new model with other results obtained computationally or experimentally. The relationship between the humidity in fuel cell and the electric potential loss within the membrane is also investigated at different nominal current densities. The impact and importance of three-dimensionality, relative humidity, temperature, and pressure non-uniformity are assessed and discussed.

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