Civil and Environmental Engineering Commons^™

Correlating Interlaminar Fatigue Fracture Behavior To Nde Parameters In Carbon/Epoxy Composites Containing Voids And Delamination, Issa Hakim, Norbert Meyendorf, Steven L. Donaldson, René Laquai, David Walter, Bernd Müller, Paul Graja

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Carbon fiber composites have been increasingly used in aerospace, military, sports, automotive and other fields due to their excellent properties, including high specific strength, high specific modulus, corrosion resistance, fatigue resistance, and low thermal expansion coefficient. Delamination, or interlaminar fracture, is a serious failure mode leading to a loss in composite stiffness and strength. Manufacturing process defects such as voids degrade the fatigue life and delamination resistance of the composite. This study investigates the effect of voids on fatigue interlaminar fracture behavior of carbon fiber composites. Samples with different vacuum levels: 0%, 50% and 100% were fabricated by varying the …

Spatial Variability Of Subsurface Soil Conditions Causing Roadway Settlements, Ömer Bilgin, Kevin Arens, Mark Salveter, Alexander Dettloff

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Settlement of problematic soils constituting the roadway subgrade may result in pavement distress and structural failure, requiring periodic pavement patching and resurfacing. Many of these problems occur as a result of the settlement of soft cohesive and organic soils. Due to the extent of roadway projects and the limited frequency of boring locations, spatial variability of subsurface soil conditions, and sometimes due to an inadequate extent of exploration, these problematic soils may not be identified suitably during subsurface explorations. An extensive subsurface exploration program was implemented for detailed characterization of subsurface conditions for a relatively short section of an existing …

Interface Friction Parameters For The Mathematical Modeling Of Shell Structures With Infill, Alexander T. Bekker, Nikita Ya. Tsimbelman, Tatiana I. Chernova, Vadim D. Bruss, Ömer Bilgin

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Thin metal or reinforced concrete shells with granular infill structures are considered in this article. These structures are massive and they are used as support for the construction of berthing quays, piers, artificial islands, shore protection, and other structures of coastal infrastructure. It is more convenient to use the thin shell structures during the development of the Arctic shelf, because it is possible to install them from the ice side. In addition, it is possible to enhance the technology and install thin shells with infill on deeper solid foundation layers. A mathematical model for the stresses on a compressible foundation …

Simulating Energy Efficient Control Of Multiple-Compressor Compressed Air Systems, Sean Murphy, J. Kelly Kissock

Mechanical and Aerospace Engineering Faculty Publications

In many industrial facilities it is common for more than one air compressor to be operating simultaneously to meet the compressed air demand. The individual compressor set-points and how these compressors interact and respond to the facility demand have a significant impact on the compressed air system total power consumption and efficiency. In the past, compressors were staged by cascading the pressure band of each compressor in the system. Modern automatic sequencers now allow more intelligent and efficient staging of air compressors.

AirSim, a compressed air simulation tool, is now able to simulate multiple-compressor systems with pressure band and automatic …

Mathematical Model Of The Shell With The Infill For Retaining Structures, Alexander T. Bekker, Nikita Ya. Tsimbelman, Dmitriy A. Potyanikhin, Andrey I. Mamontov, Ömer Bilgin, Tatiana I. Chernova

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

A description of finite element model and analysis of a shell with an infill is performed. A large diameter thin cylindrical shell structure with the edge leaning against compressible foundation soil is analyzed. Different materials are considered individually for the models of each structure shell and infill component (metal or reinforced concrete shell, and granular or elastic infill in a shell and foundation soil loaded by the structure). Contact conditions between 1) the infill and the shell’s inner surface and 2) between the foundation material and the shell edge are analyzed. An example of calculating strain conditions in the shell …

An Exploratory Survey Of Drivers’ Knowledge Of Right Of Way At Freeway On-Ramp Merging Areas, Deogratias Eustace, Stephen Owusu-Ansah, Vamsi Krishna Indupuru

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Motor vehicle crashes are one of the leading causes of death in the United States. The most recent data available show that in 2006 there were almost 6 million police-reported motor vehicle crashes in the United States where a total of 42,642 people were killed and an additional 2.6 million were injured. The majority of these motor vehicle crashes occurred at intersections or within the intersection influence areas. Traffic conflicts occur at intersections due to traffic streams moving in different directions interfering with each other, and as a result they become areas with high potential for traffic crashes compared with …

Quantifying Savings From Improved Boiler Operation, Kevin Carpenter, J. Kelly Kissock

Mechanical and Aerospace Engineering Faculty Publications

On/off operation and excess combustion air reduce boiler energy efficiency. This paper presents methods to quantify energy savings from switching to modulation control mode and reducing excess air in natural gas fired boilers.

The methods include calculation of combustion temperature, calculation of the relationship between internal convection coefficient and gas flow rate, and calculation of overall heat transfer assuming a parallel-flow heat exchanger model. The method for estimating savings from changing from on/off to modulation control accounts for purge and drift losses through the boiler and the improved heat transfer within the boiler due to the reduced combustion gas flow …

Understanding Manufacturing Energy Use Through Statistical Analysis, J. Kelly Kissock, John Seryak

Mechanical and Aerospace Engineering Faculty Publications

Energy in manufacturing facilities is used for direct production of goods, space conditioning, and general facility support such as lighting. This paper presents a methodology for statistically analyzing plant energy use in terms of these major end uses. The methodology uses as few as 60 data points that are relatively easy for most plants to obtain. Multivariable change-point models of electricity and natural gas use as functions of outdoor air temperature and production data are then developed. The statistical models can be used to predict energy use for energy budgeting, measure savings, determine cost structures, and diagnostic purposes. Moreover, in …

Estimating Energy Savings In Compressed Air Systems, Chris Schmidt, J. Kelly Kissock

Mechanical and Aerospace Engineering Faculty Publications

Compressed air is typically one of the most expensive utilities in an industrial facility. As a result, potential savings opportunities are aggressively sought out and identified. Once identified, projected energy savings must be calculated in order to justify the cost of implementing the savings opportunity. It is important to calculate projected energy and cost savings as accurately as possible. Unfortunately, savings are frequently overestimated because the methods used to estimate savings neglect to consider important factors such as compressor control and type, storage, and multiple compressor operation.

In this paper, a methodology is presented for modeling air compressor performance and …

Power Characteristics Of Industrial Air Compressors, Chris Schmidt, J. Kelly Kissock

Mechanical and Aerospace Engineering Faculty Publications

The power draw characteristics of air compressors are primarily determined by the type of compressor control and the relationship between the compressor’s output capacity and the compressed air demand in the plant. In this paper, we review the most common types of compressor control for small reciprocating and rotary air compressors, and derive relations for estimating compressed air output as a function of the type of control and motor loading. Using these relations, we develop a method to estimate the ratio of compressed air output to energy input, which we call the average operating efficiency, based on input power to …

Performance Comparison Of A Roundabout Versus Two-Way Stop Controlled (Twsc) Intersections, Deogratias Eustace

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

The superior safety record of modern roundabouts is well known in Western Europe, Australia and in most British-influenced countries around the world. The experience from a single modern roundabout installed in the City of Manhattan, Kansas, some three years ago, also shares the same experience. A major study of the performance of Manhattan, Kansas, modern roundabout was conducted at Kansas State University (KSU) and was co-sponsored by Mac-Blackwell National Rural Transportation Study Center, Kansas State University, and the City of Manhattan. The study examined three intersections, one modern roundabout and two Two-Way Stop Controlled (TWSC) intersections with similar traffic conditions. …

Techniques For Improving Energy Efficiency At Water Supply Pumping Stations, Lindell Ormsbee, Thomas M. Walski, Donald V. Chase, Wayne W. Sharp

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

This report describes the application of methods presented in Engineer Technical Letter (ETL) "Energy Efficiency at Water Supply Pumping Stations'' to the Washington, DC, and vicinity water system.

Both the ETL and this report were prepared under the Water System Operation, Maintenance and Rehabilitation Work Unit (CWIS 31794) of the Water Supply and Conservation Research Program. The technical monitors for this program in the Office, Chief of Engineers, were Mr. James Ballif (DAEN-ECE-B) and Mr. Robert Daniel (DAEN-CWP-D). The work was conducted at the US Army Engineer (USAE) Waterways Experiment Station (WES), Vicksburg, Miss., and the University of Kentucky (UK) …