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Title: STEEL STRUCTURE RESPONSE UNDER FIRE CONDITIONS MODEL BASED SIMULATION (MBS)
Creator: Coughlin, Kevin James
Date: 2019
Description: This paper addresses the issue of structure design and analysis for conditions of fire loading. It includes an introductory section that...
Show moreThis paper addresses the issue of structure design and analysis for conditions of fire loading. It includes an introductory section that presents the historical and current state of practice using prescriptive methods of design, a qualitative and conceptual development (based on actual field observations) of what is expected to occur in a structure when subjected to fire, and a summary of the current state of research on the subject of structure design for fire loading. Next, a thermo-plastic non-linear finite element shell model was developed for a two member steel beam and column, bolted joint structure used in an actual physical fire test, subjected to beam a bending load and column compressive load, held constant, while the structure was heated up in a furnace. The beam / column bolted joint rotation for the test matched the simulation quite well. Next, further extending this modeling approach, a partial moment frame from the center of a 9 story building designed for dead, live, and seismic loading was modeled with non-linear thermo-plastic shell elements in the fire zone, along with linear elastic beam / line elements for structural components surrounding the fire zone. For this model, the gravity loading (no seismic loading included) was fully applied, and then a thermal load corresponding to the ASTM E119 fire test load was applied to the structure in the fire zone. Simulation of lateral torsional buckling, flange local buckling, web local buckling, and finally overall global buckling of the columns was accomplished in this effort, increasing confidence that complex thermo-plastic structural behavior can be modeled with advanced non-linear finite element technology. Boundary conditions on this model from the floor system had a significant impact on the mode of global buckling (strong axis or weak axis), warranting further investigation and possibly a 3-D frame with a floor system included in future work. Also, extending this modeling approach even further, in future work, using the entire 9 story moment frame, with shell elements in the fire zone and non-linear moment-curvature beam / line elements for surrounding members, is contemplated, the objective being to numerically model a progressive collapse event in a planar frame. Finally, an actual 10 story structure, converted to and industrial open floor structure, based on current design codes and standards, was modeled thermally using the industry standard Hydrocarbon (HC) Temperature vs time curve, and structurally using non-linear thermoplastic shell elements in the “fire room” (to better capture local buckling and overall structure collapse behavior), and thermoplastic beam elements for the rest of the structure. The thermal modeling was performed for steel members both without insulation (bare steel) and with minimal insulation (1/4” coated thickness), and these “decoupled” results then applied to the structural model. The use of even a small layer of insulation demonstrated the dramatic effect of such, insofar as the collapse time of the structure is concerned.
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Title: Disclosure of Mental Illness in Workplace Settings
Creator: Fominaya, Adam W
Date: 2019
Description: People considering disclosure of their mental illness in the workplace have tonavigate a complex set of competing pressures to arrive at a...
Show morePeople considering disclosure of their mental illness in the workplace have tonavigate a complex set of competing pressures to arrive at a disclosure decision. Existingmodels of disclosure fail to adequately consider the role of stigma, cannot be adequatelytested with measures currently in existence, and tend to ask participants about disclosureretrospectively. These limitations were addressed using a new path model which employsmeasures currently in existence, includes stigma, and assesses disclosure motivation inindividuals who have not disclosed at work. A national sample of 365 participants wererecruited using Amazon’s Mechanical Turk Marketplace (MTurk). While thehypothesized model achieved poor fit, important findings from the models tested hereprovide clear direction for future research.
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Title: EVALUATING INTEGRITY FOR MOBILE ROBOT LOCALIZATION SAFETY
Creator: Duenas Arana, Guillermo
Date: 2019
Description: Precise localization is paramount for autonomous navigation. Localization errors are not only dangerous by themselves, but can also mislead...
Show morePrecise localization is paramount for autonomous navigation. Localization errors are not only dangerous by themselves, but can also mislead other dependent systems into moving to a hazardous location. Unfortunately, the problem of quantifying robot localization safety is only sparsely addressed in the robotics literature, and most robotics algorithms still quantify pose estimation performance using a covariance matrix or particle spread, which only accounts for nominal sensor errors. This is insufficient for life- and mission-critical applications, such as autonomous vehicles and other co-robots, where ignoring sensor or sensor or processing faults can lead to catastrophic localization errors. Thus, other methods must be employed to ensure safety.In response, this research leverages prior work in aviation integrity monitoring to tackle the more challenging case of evaluating localization safety in mobile robots. In contrast to aviation applications, that heavily rely on the Global Navigation Satellite System (GNSS) for localization, robots often operate in complex, GNSS-denied environments that require a more sophisticated sensor suite to ensure localization safety. Localization integrity risk is the probability that a robot's pose estimate lies outside pre-defined acceptable limits while no alarm is triggered. In this work, the integrity risk is rigorously upper bounded by accounting for both nominal noise and other non-nominal sensor faults, resulting in a safe upper bound on the localization integrity risk.The main contribution of this dissertation is the design and evaluation of a sequential integrity monitoring methodology applicable to mobile robot localization algorithms that use feature extraction and data association. First, faults introduced during the feature extraction and data association processes are distinguished, and the probability of the latter is rigorously upper bounded using analytical methods. The impact of faults in the estimate error's and fault detector's distributions is then determined to quantify integrity risk, which is evaluated under the worst-possible fault combination. To determine the impact of previous faults without a boundlessly growing number of fault hypotheses, this dissertation presents a novel method that uses a preceding time window to build a limited set of hypotheses and a prior estimate bias to account for faults occurring before the start of the time window. The proposed methodology is applicable to Kalman Filter and fixed-lag smoothing localization. Simulated and experimental results are presented to validate the methodology.
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Title: Language, Negative Affect, and Aggression in Children with Autism Spectrum Disorder
Creator: Dreher, Taylor
Date: 2019
Description: The goal of the present study was to use ecological momentary assessment to examine factors that predict aggression in children with Autism...
Show moreThe goal of the present study was to use ecological momentary assessment to examine factors that predict aggression in children with Autism Spectrum Disorder (ASD). In particular, this study sought to investigate the situation-level and person-level factors that predict the severity of children’s aggressive episodes. At the situation-level, we predicted that children would show more severe aggression after experiencing a negative affective state. At the person-level, we hypothesized that children with better grammatical and pragmatic language abilities would demonstrate less severe aggressive behavior. In addition, we predicted that language abilities would moderate the association between negative affect and aggression. We were unable to test these hypotheses due to a floor effect in the outcome variable. Thus, we conducted a series of analyses to examine how variables of interest were associated with the presence of aggressive behavior. We found an association between negative affect and aggression, such that children who experienced higher levels of negative affect were more likely to engage in aggressive behavior. However, there was not a significant relationship between language abilities and the presence of aggression. In addition, there was no evidence for a moderation effect. Future studies should examine other variables that may moderate or mediate the association between negative affect and aggression in children with ASD.
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Title: Three-legged race, Illinois Institute of Technology, Chicago, Illinois, 1980s
Date: 1980-1989
Description: Photograph of a three-legged race at an unidentified event on the Illinois Tech campus. Photographer unknown. Date of photograph unknown. Date...
Show morePhotograph of a three-legged race at an unidentified event on the Illinois Tech campus. Photographer unknown. Date of photograph unknown. Date range listed is approximate.
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Collection: Office of Communications and Marketing photographs, 1905-1999

Title: Doing physics : a festschrift for Thomas Erber
Creator: Johnson, Porter Wear
Date: 2010, 2010
Publisher: IIT Press, Chicago, IL
Description: Doing Physics is a festschrift (collection of articles, essays, and rememberances) published in honor of Illinois Tech Physics professor...
Show moreDoing Physics is a festschrift (collection of articles, essays, and rememberances) published in honor of Illinois Tech Physics professor Thomas Erber's 80th birthday. Selections were authored by Erber's colleagues, former stduents, and fellow scholars. This book was released in print form, this file was the original pdf assembled by editor Porter Johnson and submitted for printing with the front and rear covers added.
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Title: Benjamin de Brie Taylor, 1970s
Date: 1973-1979
Description: Benjamin de Brie Taylor was Director of the Institute of Design at IIT from 1973 to 1975, and remained on the faculty at ID until 1987. Date...
Show moreBenjamin de Brie Taylor was Director of the Institute of Design at IIT from 1973 to 1975, and remained on the faculty at ID until 1987. Date of photograph is unknown. Date range listed is approximate.
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Title: Benjamin de Brie Taylor, 1970s
Date: 1973-1979
Description: Benjamin de Brie Taylor was Director of the Institute of Design at IIT from 1973 to 1975, and remained on the faculty at ID until 1987. Date...
Show moreBenjamin de Brie Taylor was Director of the Institute of Design at IIT from 1973 to 1975, and remained on the faculty at ID until 1987. Date of photograph is unknown. Date range listed is approximate.
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Title: Systems and Systematic Design: Tracing the Evolution of Design Methodology at the Institute of Design, 1965-2010: Slides
Creator: Owen, Charles L.
Date: 2010-10-28
Collection: Charles L. Owen presentation, 2010

Title: László Moholy-Nagy at the Institute of Design, Chicago, Illinois, 1944
Date: 1944
Description: Photograph of Laszlo Moholy-Nagy at the Institute of Design (or possibly the School of Design before it was renamed the Institute of Design in...
Show morePhotograph of Laszlo Moholy-Nagy at the Institute of Design (or possibly the School of Design before it was renamed the Institute of Design in 1944). Photographer unknown.
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Collection: Biographical files collection, 1900-2014

Title: Unbreakable wooden springs, ca. 1942
Creator: Halbe, Milton
Date: 1942
Description: Photograph of a design for unbreakable wooden springs, possibly designed by Glenn Foss. Superimposition of two photographs shows the...
Show morePhotograph of a design for unbreakable wooden springs, possibly designed by Glenn Foss. Superimposition of two photographs shows the deflection of weight. Date of photograph is unknown. Date listed is approximate.
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Collection: Institute of Design records, 1937-ca. 1962

Title: What student responses do middle school mathematics teachers anticipate for contextualized and decontextualized problems about linear relationships?
Creator: Rupe, Kathryn Mary
Date: 2019
Description: The recent transition to the Common Core State Standards for Mathematics is in line with current initiatives to improve mathematics teaching...
Show moreThe recent transition to the Common Core State Standards for Mathematics is in line with current initiatives to improve mathematics teaching and learning through the emphasis of conceptual understanding and mathematical reasoning. Much research has been done on how to develop conceptual understanding for students in kindergarten through twelfth grade. Stein, Engle, Smith, & Hughes (2008) highlighted the importance of orchestrating productive classroom discussions. They suggest that this goal can be attained through the process of five steps, each depending on the previous step. Teachers must anticipate student responses to a task that will be taught, monitor student thinking as they are engaged in the task, purposefully select students to present based on their choice of representations, sequence those representations in a purposeful way, and then make connections among the representations so that students are able to understand key concepts. The first step in this process, anticipating student responses (ASR), is an area where little research has been done. The literature suggests that teachers that engaged in professional learning related to the practice did so at varying levels (Empson et al., 2017), and could develop those skills over time with explicit feedback (Popovic, Morrissey, & Kartal, 2018). However, research on average middle school mathematics teachers, those that were not enrolled in any professional learning focused on ASR, was absent from the literature. This study aimed to understand middle school mathematics teachers’ anticipation of student responses. A sample of 19 eighth grade math teachers that represented a variety of years of experience and curriculum use (traditional, reform, and teacher-developed) participated in semi-structured interviews and completed four common eighth grade math problems focused on the content of linear relationships and systems. Teachers’ anticipated student strategies were categorized as showing robust, moderate, limited, or lacking evidence of ASR. Based on the results, all of the teachers fit into one of four categories: those that anticipated student responses at (1) consistently high levels, (2) mixed levels, (3) consistently low levels, and (4) inconsistent levels. The results of this study found teachers who anticipated student responses at consistently high levels were experienced (over 10 years of experience), had numerous student-centered professional development experiences, considered their teacher-role as that of a facilitator, and had high expectations for students. They differed with respect to the type of curriculum they used, the certification they held, and the level of detail in their planning practices. Several of the teachers inconsistently anticipated student responses, providing robust and limited evidence for at least one problem. This speaks to the specialized knowledge that teachers have, what Hill and Charalambous (2012a) refer to as local mathematical knowledge for teaching. Among all of the variables considered, curriculum use did not appear to have an impact on teachers’ skills and knowledge related to anticipating student responses, although teachers used their curriculum materials in very different ways. Years of experience, secondary licensure, a student-centered philosophy of teaching, and teachers that described their role as that of a facilitator related to evidence of anticipating student responses. Understanding the variables that may impact teachers’ abilities to anticipate student responses, the first of five steps outlined by Stein et al. (2008), is important for supporting teachers as they orchestrate productive classroom discussions around important concepts.
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Title: Comparing Complex Network and Latent Factor Models of Seasonal Affective Disorder
Creator: Smetter, Joseph
Date: 2019
Description: Research on Seasonal Affective Disorder (SAD) has produced several etiologicalmodels of SAD symptomatology, including a common cause model...
Show moreResearch on Seasonal Affective Disorder (SAD) has produced several etiologicalmodels of SAD symptomatology, including a common cause model that conceptualizessymptoms as the result of a single underlying disease process, and the Dual VulnerabilityModel (Young et al., 1991) which posits that psychological symptoms of depressionfollow the onset of vegetative symptoms (e.g. hypersomnia, increased appetite) inindividuals with a vulnerability to seasonal changes. Studies of the structure of SADsymptomatology have been limited in their ability to evaluate these models. This studyused exploratory factor analysis and network analysis to examine baseline winter SADsymptoms (using a modified BDI-II) in 177 adults participating in a randomizedcontrolled trial of light treatment and CBT for SAD (Rohan et al., 2015). The factoranalysis supported a four-factor model that included negative cognition/affect, loss ofvitality, dysregulation, and increases in weight/appetite. The complex network model ofSAD conceptualized the network as a system of interacting symptoms. Results of thenetwork model paralleled those of the factor analysis in producing four communities ofinter-correlated symptoms. In addition to the full symptom network, a directed acyclicgraph was constructed to model causal relations between symptoms. Results suggest thatvegetative symptoms (loss of vitality and appetite/weight) lead ultimately to cognitivesymptoms, with intermediate effects of dysregulation symptoms. This partially supportsthe Dual Vulnerability model. Findings from the factor analysis and the network analysisare compared, and their implications for and treatment of SAD is discussed.
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Title: DEEP LEARNING FOR IMAGE PROCESSING WITH APPLICATIONS TO MEDICAL IMAGING
Creator: Zarshenas, Amin
Date: 2019
Description: Deep Learning is a subfield of machine learning concerned with algorithms that learn hierarchical data representations. Deep learning has...
Show moreDeep Learning is a subfield of machine learning concerned with algorithms that learn hierarchical data representations. Deep learning has proven extremely successful in many computer vision tasks including object detection and recognition. In this thesis, we aim to develop and design deep-learning models to better perform image processing and tackle three important problems: natural image denoising, computed tomography (CT) dose reduction, and bone suppression in chest radiography (“chest x-ray”: CXR). As the first contribution of this thesis, we aimed to answer to probably the most critical design questions, under the task of natural image denoising. To this end, we defined a class of deep learning models, called neural network convolution (NNC). We investigated several design modules for designing NNC for image processing. Based on our analysis, we design a deep residual NNC (R-NNC) for this task. One of the important challenges in image denoising regards to a scenario in which the images have varying noise levels. Our analysis showed that training a single R-NNC on images at multiple noise levels results in a network that cannot handle very high noise levels; and sometimes, it blurs the high-frequency information on less noisy areas. To address this problem, we designed and developed two new deep-learning structures, namely, noise-specific NNC (NS-NNC) and a DeepFloat model, for the task of image denoising at varying noise levels. Our models achieved the highest denoising performance comparing to the state-of-the-art techniques.As the second contribution of the thesis, we aimed to tackle the task of CT dose reduction by means of our NNC. Studies have shown that high dose of CT scans can increase the risk of radiation-induced cancer in patients dramatically; therefore, it is very important to reduce the radiation dose as much as possible. For this problem, we introduced a mixture of anatomy-specific (AS) NNC experts. The basic idea is to train multiple NNC models for different anatomic segments with different characteristics, and merge the predictions based on the segmentations. Our phantom and clinical analysis showed that more than 90% dose reduction would be achieved using our AS NNC model.We exploited our findings from image denoising and CT dose reduction, to tackle the challenging task of bone suppression in CXRs. Most lung nodules that are missed by radiologists as well as by computer-aided detection systems overlap with bones in CXRs. Our purpose was to develop an imaging system to virtually separate ribs and clavicles from lung nodules and soft-tissue in CXRs. To achieve this, we developed a mixture of anatomy-specific, orientation-frequency-specific (ASOFS) expert deep NNC model. While our model was able to decompose the CXRs, to achieve an even higher bone suppression performance, we employed our deep R-NNC for the bone suppression application. Our model was able to create bone and soft-tissue images from single CXRs, without requiring specialized equipment or increasing the radiation dose.
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Title: ON THE FLOW AND PERFORMANCE OF MUTUAL FUNDS
Creator: Zhang, Jingqi
Date: 2019
Description: ABSTRACTThis dissertation consists of three essays on mutual funds. I first discuss the flow of active ETFs. And then I focus on the...
Show moreABSTRACTThis dissertation consists of three essays on mutual funds. I first discuss the flow of active ETFs. And then I focus on the performance of mutual funds. Finally, I evaluate the timing ability of mutual fund investors.Using a data set from 2000 to 2016, this thesis first studies the behavior of active ETF investors from the perspective of fund flows. The results show that the investors chase past returns as they do for mutual funds. Furthermore, I find that the return-chasing behavior can be influence by other considerations, such as fee changes. However, the evidence of performance persistence is weak for active ETFs. Therefore, I propose that the return-chasing behavior is not smart, and the flows of active ETFs instead behave more like “dumb money”, which are demonstrated by the data.I continue to study the performance of the mutual funds. To avoid the bias caused by pricing models themselves, I introduce a model-independent method to assess the mutual fund performance relative to the portfolios constructed by ordinary investors, assuming they are following a naive strategy. Using a data set from October 1984 to September 2017, I find that the majority of mutual funds have higher buy-and-hold returns than the T-bill returns as well as the market returns in the long run. And employing the model-independent measure of performance, I find that the mutual fund industry creates value for individual investors for that mutual funds on average exceed the performance of the majority of the portfolios constructed by the investors selecting stocks randomly.To measure the timing ability of mutual fund investors, I use the difference between the internal rate of return realized by investors and the buy-and-hold return of the funds. Different from the existing literature, I modify the cash flows used to generate the internal rate of return, in which way I can capture the realized return of investors more accurately. I find that investors show timing skills in short horizon. And on average, investors of mutual funds have worse timing skills than those of ETFs. And compared with active fund investors, passive fund investors have better timing skills. I also find that investors who simply chase past winners would show worse timing skills.
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Title: Inefficiencies in resource allocation games
Creator: Tota, Praneeth
Date: 2019
Description: This thesis addresses a problem that has been debated by the academic community, the government and the industry at large which is : How...
Show moreThis thesis addresses a problem that has been debated by the academic community, the government and the industry at large which is : How unfair is a tiered Internet compared to a open Internet ? On one hand we have an open Internet in which all the data is treated equally and the Internet service providers have no say when it comes to a pricing differentiation and on the other hand we have a tiered Internet in which the ISPs can charge different amounts based on certain constraints like the type of data or the content provider. The architecture of the internet imposes certain constraints which need mechanisms to efficiently allocate the resources among all the competing participants who only concern themselves with their best interests without considering the social benefit as a whole. We consider one such mechanism known as proportional sharing in which resource or the bandwidth is divided among the participants based on their bids. An efficient allocation is one which maximizes the aggregate utility of the users. We consider inelastic demand with the participants as price anticipating and ensure market clearing.We examine a tiered Internet in which the ISPs can partition the bandwidth based on certain constraints and charge a premium for better service. The participants involved are from all economic classes, so they have different amounts of wealth at their disposal. We quantify the relative loss incurred by the participants in lower economic classes as compared to the higher economic classes. We also calculate the loss of efficiency caused by competition among the participants as compared to the optimum social allocation.
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Title: Structural Uncertainty Analysis of Nuclear Reactor Core Load Pads
Creator: Wozniak, Nicholas
Date: 2019
Description: In fast spectrum nuclear reactors, reactivity is directly related to the capability of the reactor to sustain a fission chain reaction for...
Show moreIn fast spectrum nuclear reactors, reactivity is directly related to the capability of the reactor to sustain a fission chain reaction for power production. Historically, mechanical/structural analysis and design have been driven primarily by deterministic methods. However, reactivity is extremely sensitive to the location of the fuel within the reactor; which is subject to uncertainties. This makes deterministic models unstable and can allow manufacturing errors to contribute to uncertainties in analysis, resulting in potential safety concerns and incorrect reactor lifetime prediction. One potential means to address this challenge is the use of stochastic analysis. A framework is presented which introduces uncertainty analysis through the use of Monte Carlo Simulation. Latin Hypercube Sampling is used to reduce the number of sample runs and the computational effort and storage space requirements for the results. Geometric parameters such as the gaps at the load pad contact points, the location of the above core load pad (ACLP), and even temperature gradient profiles, that are important to the design of nuclear reactors are varied, and their effects on the overall performance are studied through sensitivity analysis. The main focus was to quantify the effects of the variation of these parameters directly on the variation of the contact forces and deformations of the fuel assemblies which house and control the movement of the fuel. Based on the results of the sensitivity study, this study found that the ACLP location has the largest effect on contact forces. And as such, any uncertainty in this parameter results in a rather large variation in the intensity of the contact force. Furthermore, specific recommendations are given to help control these variations as well as for further investigations on other parameters that may be significant to the design of fuel assemblies.
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Title: CHARACTERIZATION OF DISPERSION AND ULTRAFINE PARTICLE EMISSION FACTORS USING NEAR ROADWAY FIELD MEASUREMENTS
Creator: Xiang, Sheng
Date: 2019
Description: Recent epidemiology evidence suggests that vehicle emissions are major contributors to poor urban air quality. Human exposure to elevated...
Show moreRecent epidemiology evidence suggests that vehicle emissions are major contributors to poor urban air quality. Human exposure to elevated concentration of traffic emissions has been associated with increased risk factors for a range of negative health outcomes. Evaluation of human exposure to vehicle emissions (e.g. ultrafine particles) mainly relies on dispersion models. Consequently, dispersion models need to comply with constantly increasing requirements to provide predictions of pollutant concentration. The dynamic of near roadway dispersion process needs to be investigated since most of the existing models does not account traffic condition variability (e.g. vehicle type and mode of operation) for dispersion. A five-year long field study was conducted to characterize dispersion near roadway with various vehicle mode of operation and vehicle type. To better understand the dispersion process near roadway, the impact of different ambient background categories (e.g. remote, lake, urban, industrial) on ultrafine particles (UFPs) need to be evaluated. Results demonstrate that each category has a different average ambient background concentration (pt cm–3) as follows: remote, 2,700; lake, 6,000; industrial 12,000 and urban 11,000. The large variations exist in ambient background concentration will result in significant variations in near roadway concentrations. The total near roadway measurements are generally near 20,000 pt cm–3 and reach to 60,000 pt cm–3 depending on the background and traffic emission. The dispersion near the roadway is also investigated in this study. A roadway restricted to light-duty vehicles (LDVs) was selected to conducted near roadway field measurement. Results indicate that the dispersion induced by vehicles is a two-stage process. When under the unsteady-state condition with small number of operating vehicles, the rate of dispersion near roadway increased from 2 m2 s-1 to 6 m2 s-1 as the number of vehicles increased. For steady-state condition, the rate of dispersion was constant near 6 m2 s-1 and not increased with additional vehicles. For a roadway mixed with both LDVs and heavy duty vehicles (HDVs), similar results were found. Dispersion increased from 6 to 18 m2 s-1 as total vehicle flow rate increased to 10,000 veh h-1 and HDV flow rate increased to 1000 veh h-1. Finally, the calculated dispersion near roadway is used to estimate the UFP emission factors. The UFP emission factors were ranged from 0.5 × 1013 to 1.5 × 1013 pt km-1 veh-1 and from 7 × 1014 to 20 × 1014 pt km-1 veh-1 for LDVs and HDVs, respectively. The variations in UFP emission factors are due to change in vehicle mode of operation.The results from this study will be critical for parameterization of dispersion near roadway and provide important emission inventory for interdisciplinary partnership among different fields (e.g. air quality, transportation design and urban planning) in solving transportation air quality problem.
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Title: Structural Condition Assessment for Wind Turbine Towers
Creator: Zahraee, Afshin
Date: 2019
Description: Wind-based energy generation has special priority in efforts related to global sustainability. Based on this priority and the desire for...
Show moreWind-based energy generation has special priority in efforts related to global sustainability. Based on this priority and the desire for increase in electricity generation, the size of wind turbines has been tremendously increased in recent years. Moreover, larger wind turbines have access to more stable wind speeds which assists in electricity generation consistency. However, larger wind turbines are more prone to exhibit structural failure due to the increase of size as well as presence of complexities in the structure and wind load interaction. As such, condition monitoring and fault diagnosis of wind turbines are crucial in their sustainable operation. In this work, a new framework for condition assessment of wind turbine towers is developed. This framework enhances the ability to assess the structural condition of in-service wind turbine towers. Using this framework: 1) the wind data for the wind turbine location is collected, 2) a series of numerical modeling and analysis for the wind turbine tower for various wind velocities are performed to obtain the maximum induced stresses and their corresponding critical fatigue components (hot spots), and 3) fatigue analysis is performed leading to prediction for the remaining life of the wind turbine tower. To illustrate the capability of the present method, a case study is performed on an existing wind turbine. The obtained analytical results are compared and verified by the original design parameters. The results obtained for life prediction of the wind turbine tower correlate with life predictions of other existing wind turbine towers. It is anticipated that application of this framework for existing and future wind turbines will enhance their inspection planning as well as offer a more cost-effective process for repair and rehabilitation of wind turbine towers. This will ultimately increase the overall safety of wind turbine systems and enhance their reliability of performance.Keywords: Wind Turbine Tower, Condition Assessment, Life Prediction.
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Title: Spring Thing tricycle race, Illinois Institute of Technology, Chicago, Illinois, 1970
Date: 1970
Description: Photograph of the tricycle race during the 1970 Spring Thing. Spring Thing, sponsored by the Union Board, occurred during the fall semester,...
Show morePhotograph of the tricycle race during the 1970 Spring Thing. Spring Thing, sponsored by the Union Board, occurred during the fall semester, usually in October. The tricycle race, first held in 1968, was a highlight of the annual festivities. Photographer unknown.
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Collection: Office of Communications and Marketing photographs, 1905-1999

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