In armored platforms industry, the dominant material solution for ballistic transparency protection applications is relatively low-cost polycarbonate matrix glass. This research work aims to investigate the effects of geometrical designs of the amalgamated layers, engineering characteristics of the materials, and the interaction of both on the ballistic resistance of the transparent armor. The resulted models are used to analyze the strength feasibility of the material in the cost base. Ballistic measurements over a wide range of impact velocities including those well above the ballistic limits are deployed to the model. Under simple loading conditions, the polycarbonate matrix glass or ceramic can be regarded as elastic-brittle materials, however, when considering ballistic impacts the post-yield response of the ceramic becomes significant. A post-yield response model of ceramic materials is used for simulating the characteristics. The model incorporates the effect of damage on residual material strength and the resulting bulking during the compressive failure of the ceramic. A combination of relevant factors including the ability to dissipate ballistic energy and manufacturing processes was considered for the proper evaluation and selection of the armor. The model has been implemented into computer software to predict unsuccessful solutions and optimize the amalgamation with capabilities of defeating a wider range of ballistic impacts. The results will show more physical insight of the behavior and performance of the complex armor systems and provide guidelines/principles for the design and selection of the constituent materials.

Numerical models were conducted to study the load/momentum/energy transfer to the clay and the clay response when it was used as backing behind hard and soft armor during ballistic experiments. Tie-break contacts were used to explicitly model the delamination in the composite panels. Yarn level models accounting for woven structures were used to model the soft armor. A rate-dependent material model with different responses under compression and tension, developed previously from impact tests, was used to model the clay. The clay indent depth was correlated to the momentum and kinetic energy transferred to the clay for with and without soft armor between the hard armor and clay backing.

The manufacture of relatively low commercial value ceramic products for construction is an energy intensive industry. It is important to improve and optimize the energy equation of the plant operation while simultaneously introducing renewable primary energy sources for the heat supply. The present paper concerns the analysis of the energy usage in a brick plant. This unit operates continuously on a 3 shift schedule. The overall annual production of five types of bricks is over 62 kton and the main energy consumption unit is the furnace. For this unit, the thermal load is supplied mainly by biomass coupled with fuel oil (80%–20% split, respectively) which yield a maximum temperature of 950 °C. The process is controlled by adjusting the air mixing in the kiln. A secondary furnace provides the heat for a rotating dryer for biomass drying which is supplied to the main furnace. The fuel is a mixture of various sources and its characteristics were determined by means of an elemental analysis, ash content and the measurement of the heat value. Measurements of mass fluxes along with the operating temperature on critical elements of the plant and chemical composition of the flue gases were used to calculate the energy balances to the plant. Because of the diversity of the product mix the production was normalized using the mass/surface area ratio of the various types of bricks. From the results, the energy intensity is 44 kg of oil equivalent per ton. The exergy analysis of the plant shows that most of the energy degradation occurs in the kiln. The analysis also enabled to assess the influence of the replacing fossil fuel by biomass on the increase of exergy efficiency of the plant.

Dielectric Barrier Discharge plasma actuators are simple devices with great potential for active flow control applications. They have very interesting features which have made them a topic of interest for many researchers, for instance they present very low mass, fast response time, low cost, easy implementation and they are fully electronic with no moving parts. The dielectric material used in the construction of these devices present an important role in their performance. The variety of dielectrics studied in the literature is very restrict and the majority of the authors make use of Kapton, Teflon, Macor ceramic or PMMA. Furthermore, several authors reported difficulties in the durability of the dielectric layer when actuators operate at high levels of voltage and frequency. Considering this background, the present study focus on the experimental testing of alternative dielectric materials which can be used for DBD plasma actuators fabrication. Considering this, plasma actuators with dielectric layers made of Poly-Isobutylene rubber, Poly-Lactic acid and Acetoxy Silicon were experimentally tested. Although these dielectric materials are not commonly used in plasma actuators, their values of dielectric strength and dielectric permittivity indicate they can be good solutions. The plasma actuators facbricated with these alternative dielectric materials were experimentally analysed in terms of electrical characteristics and induced flow velocity, and the obtained results were compared with an actuator made of Kapton which is, currently, the most common dielectric material for plasma actuators. The effectiveness of the actuators was estimated and the advantages and disadvantages of the use of each dielectric material were discussed.

Thermal Barrier Coatings have been widely used in modern turbine engines to protect the nickel based metal substrate from the high temperature service conditions, 1600–1800 K. In this study, some of the failure mechanisms of typical Air Plasma Sprayed Thermal Barrier Coatings (TBC) used in after-burner structures composed of three major layers: Inconel 718 substrate, NiCrAlY based metallic bond coat (BC) and Yttria Stabilized Zirconia (YSZ) based ceramic top coat (TC) are investigated. Investigation of the cracking mechanism of TBC in terms of design and performance is very important because the behavior of TBCs on ductile metallic substrates is brittle. To this end, four-point bending experiments conducted in Kütükoğlu (2015) is analyzed by using the Extended Finite Element Method (XFEM). All the analyses are conducted with the commercial finite element software ABAQUS. Three different models with varying TC and BC thicknesses are studied under four-point bending. It is observed that multiple vertical cracks are initiated in the TC. Cracks initiate at the top of YSZ and propagate through the whole TC. It is observed that the average crack spacing increases with the increasing thickness of the TC. Numerical results are found to be consistent with the experimental results. In other words, the average crack spacing for three different models are similar with the experimental results.

A very challenging issue about solar thermal power generation is the use of a high temperature heat transfer fluid (water, oils, or molten salts) for heat transfer and thermal storage material, which may freeze at night or cold weather. When choosing air as the heat transfer fluid, the problem of freezing is eliminated. In order to increase the performance of thermal storage system which uses air as the heat transfer fluid passing through a packed bed (by ceramic spheres of Al 2 O 3 ), multiple small-diameter tanks are considered to replace a single large-diameter tank with the same packed-bed volume and airflow rate in this paper. Analysis about the thermal storage performance in a short big tank and in cascade thin tanks has been made for comparison. A long passage of airflow and faster flow speed of air in the cascade thin tanks has been found significantly beneficial to thermal storage. Results about the increased thermal storage performance and increased pressure loss will be presented. Longer passage of airflow made it possible to have a longer time of high temperature of outflow air during discharging period. And faster speed of the fluid enhanced the heat transfer between air and thermal storage material. The total effective energy and thermal storage efficiency of cascade thin-tank thermal energy storage (TES) are higher. The thermal storage efficiency in the two types of thermal storage arrangement was compared for optimal design. The obtained results are of great significance to the development of using air as heat transfer fluid and rocks or ceramic spheres as the thermal storage material for thermal storage system in concentrated solar thermal power plants.

A successful approach to the development of reinforced materials for enhanced cutting tool inserts requires the formulation and application of innovative concepts at each step of material design development. In this paper, reinforced ceramic-based cutting tools with enhanced thermal and structural properties are developed for high-speed machining applications using a computational approach. A mean-field homogenization, effective medium approximation and J-integral based fracture toughness evaluation using an in-house code are used for predicting the effective structural and thermal properties for tool inserts as a function of reinforcement type, volume fraction, particle size and interface between matrix and reinforcement. Initially, several potential reinforcements are selected at the material design phase. SiC, TiB 2 , cBN and TiC were all found to be suitable candidates when reinforced into an alumina matrix as both single and hybrid inclusions for the enhancement of thermal and structural properties. For validation purposes, alumina-cubic boron nitride-silicon carbide composites are developed using Spark Plasma Sintering as hybrid systems, which are in line with the designed range of volume fraction and reinforcement particle size. Structural and thermal properties such as elastic modulus, fracture toughness and thermal conductivity are measured to complement the computational material design model.

During the machining processes of ceramic particle reinforced metal matrix composites, the severe tool wear constrains the quality and cost of the parts. This paper presents the experimental and theoretical investigations of the tool wear behavior and surface quality when micro milling the 45vol% SiCp/Al composites under dry and minimum quantity lubrication (MQL) conditions. The results of scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) show that the wear mechanism of diamond coated micro mills are adhesive, abrasion, oxidization, chipping and tipping, even though it has been reported that abrasion is the most important tool wear mechanism when machining particle reinforced metal matrix composites. Compared with dry lubrication condition, the environmentally friendly MQL technique can enhance the tool life and surface roughness, and reduce the cutting force significantly under given cutting parameters. Then, finite element (FE) simulations are employed to investigate chip formation process in micro orthogonal cutting to reveal the effects of reinforced particle on tool wear and surface quality. The FE simulations shows the local high stress, hard reinforced particles in metal matrix, debonded and cracked particles are the key factors leading to the severe tool wear and the unsmoothed surface morphology.

The use of additive manufacturing (AM) provides an opportunity to fabricate composite tooling rapidly and cost effectively. This project appears to have demonstrated the use of an additive technology for the production of composite processing tools. In particular, this work has addressed tooling that is functional in the range of autoclave temperatures around 300–350°F. This has led to the use of Invar and ceramic materials for use in composite molding tools because of their relatively low coefficient of thermal expansion (CTE) performance, which is in range to that commonly displayed by carbon fiber reinforced composites during their solidifying-curing process. In this project, two main approaches have been considered. The first approach consisted on using binder jetting for 3D printing sand molds to cast molten Invar to produce the composite tooling. Indeed, 3D sand printing offers the ability to cast complex geometries without the geometric limitations associated with conventional pattern making. The second innovative approach was based on printing a mold based on silica sand and infiltrating it with a polymer to yield a robust ceramic composite tooling. An additional technology using a Hybrid Direct Energy Deposition (DED) System for cladding Invar upon a steel molding structure has also been considered for producing potential composite tooling. Indeed, this unique approach could represent a promising technology for producing low cost composite tooling since only a small layer of Invar would be printed upon a non-expensive substrate. The results have shown that the aforementioned processes have successfully resulted on low CTE composite tooling molds. This work presents innovative AM processes by initially investigating 3D ceramic systems for composite tooling.

The manufacturing of hard and refractory materials such as ceramics, glass or carbide poses particular challenges on tools and machines. The Sauer Limited a company of the DMG Mori Corporation has developed ultrasonic tool holders working in a frequency range from 15 to 60 kHz. The ultrasonic vibrations are superimposing the tool movement in the tool axis especially for the application on special materials. This technique causes a structural weakening in the contact area and facilitates the machining. For these special materials, a force reduction, mainly in drilling into carbide with diamond tools, of up to 30 percent is possible. This made the authors try to expand the application range of this method. To achieve evaluable results, the authors decided to start working with existing processes. This also makes it easier to understand the mechanism of the positive influence of the ultrasonic assistance. It is difficult to compare a grinding process of hard and brittle materials to the drilling of steel as these two operations are different in many ways. In the first case of investigation, the authors use tools with geometrically undefined edges, where as in the second case, the edges are geometrically defined. To get valid results of the tests, it has then been decided to investigate drilling. This manufacturing method anticipates the best results. The main target of the investigation is to reduce the cutting force. It is measured with a force measurement platform underneath the workpiece. Concerning the direction of the ultrasonic assistance, the authors expect lower cutting forces, longer endurance of the tool, a reduction of the burr height and a better surface quality in the drilling process. To verify the frequencies and the amplitudes, an FFT-analysis is performed. This analysis shows the increase of the damping. This raise depends on the infeed rate of the tool and thus reduces the amplitude of the cutting force.

Additive Manufacturing (AM) processes have vastly improved over the years and 3D-printed parts are no longer solely being used for prototyping but also as final products. Where AM parts are used in low-volume products, nondestructive testing is critical to validate product performance. This paper will discuss using an infrared thermography technique known as Pulsed Thermography (PT) based on the analysis of a theoretical one-dimensional solution as a nondestructive testing method for quantitatively measuring defect depths within a 3D-printed part made from a thermoplastic ABS. This method has previously been applied to composites, ceramics, and metals for quantification of defects, but no work has been done for thermoplastic 3D printed parts. This technique can potentially be integrated into existing equipment for online monitoring during part construction. This paper will demonstrate the ability of a low-cost PT system to characterize the surface of 3D-printed parts and detect the effect of common parameter variations. The capability of a PT system as a viable NDT method to quantitatively analyze a 3D-printed part would allow for post process quality control in comparison to initial design and simulation.

Application of 3D printing to works of art is not new. However, with the advent of larger and more affordable 3D printers, it is possible to fabricate works of art including statues, sculptures, and architectural structures from biomimicked composites. Made of hard ceramic and soft polymer with or without reinforcement, these composites have shown to be much tougher than their monolithic counterparts. The use of biomimicking will increase the durability and strength of such artifacts. In this study, a newly developed architectural 3D printer is used to create works of art using concrete, with and without reinforcement fibers. The challenge that face creating tough artistic display structures include durability, hardness and resistance to impact. To determine the right combination of hard ceramic and soft polymer, a series of experiments were conducted. These included the fabrication of biomimicked composites with different materials and testing them for fracture energy as well as maximum strength. Earlier published works demonstrate the effect of various parameters such as type of ceramic layer, layering, fiber reinforcement type, fiber length, and fiber loading. In this paper, the effect of hard layer thickness and the type of polymer on the mechanical properties of the biomimicked composites was investigated. Preliminary results show the highest fracture energy for composites made with concrete bonding adhesive (CBA) and Quikrete™ concrete, with a spacing of 5mm. The application of 3D printing to the educational activities of a museum in Newport KY will be explained and its implication in relation with civic engagement activities of Northern Kentucky University will be elucidated.

An investment firm located in Peru has partnered with Western New England University to develop a novel, motorcycle mounted fast food delivery system for international markets. The project afforded students the opportunity to work on an international product development team, exposing them to the design requirements and constraints of international customers and companies. The often damp and cool climate in many countries makes food prone to becoming soggy during delivery as the moisture escaping from the hot food quickly fills the food containers and delivery box mounted to the back of the motorcycle, saturating the food. Delivery times, often in excess of 45 minutes, can also cause the food to become cold, resulting in decreased customer satisfaction, product returns and lost business. The project was conducted over a three year period using nine mechanical engineering students. The project began in 2014 when a team of two students was tasked with developing a benchtop method of keeping food hot and preventing it from becoming soggy while being delivered. They determined that the use of ceramic heaters and small fans effectively kept the food warm and dry. In 2015, two teams of two students competed to develop a box design with integrated heaters and fans which could be powered using an alternator mounted to a delivery motorcycle. While effective fans and heating elements were found, it was decided that the mounting of an additional alternator was cumbersome and motorcycle dependent, rendering the concept poorly suited for field installations. In 2016 another team of two students integrated a hand-made lithium ion Battery pack and two 300W ceramic heaters and computer fans into a production delivery box. While the system maintained food quality for up to 50 minutes, the battery pack was unable to reliably provide the required power to the system. Finally, in the fall of 2016, a student improved this design by improving the heater and fan performance while adding urethane insulation into the box. Temperature was controlled using a commercially available thermistor, and all components were integrated into a retrofit kit which could be installed by a technician in the field. The power requirement was reduced by over 50% and the system operated for 110 minutes using two, commercially available 27 Ah lithium iron phosphate batteries. Students gained global perspective of the product development process as they experienced the effects of various cultures on the requirements of customers and the international design and marketing team.

Strong shear force developed in the fluid film as the water-lubricated hybrid bearing operates at high speeds. Thus the phenomena of shaft expanding outward and bearing contracting inward happened due to the increasing temperature of the fluid film caused by the friction heat. So the bearing clearance decreases on account of the thermal deformation of the shaft and the bearing. Seriously, there will be a risk of seizure accident when the speed gets higher. Friction heat may be weakened by adopting low viscosity lubricant and thermal deformation may be reduced by adopting low expansion coefficient materials. Such as the ceramic’s expansion coefficient is 3–5 times smaller than that of typical journal bearing material like tin bronze. Thus, a ceramic journal bearing was developed in this paper to weaken the thermal influence on the bearing clearance. For improving the temperature rise of the journal bearing, a water-lubricated ceramic hydrodynamic-hydrostatic hybrid bearing test rig was designed firstly. Considering expansion coefficient and thermal conductivity effects, the simulation method was used to study the variation of bearing clearance with the speed and the original bearing clearance. Then, the water-lubricated ceramic hydrodynamic-hydrostatic hybrid bearing test rig was developed to verify the temperature characteristics at different speeds. Results indicate that the relative error of the tested temperature results and simulation results was below 10% at different speeds. Lastly, the evolution of bearing clearance with speed and the original bearing clearance was studied through FEM. The advantages of ceramic material were more obvious with the increase of the rotation speed when exceeds 8000rpm.

Polymer-derived ceramics (PDC), prepared through thermal decomposition of polymeric precursors, are piezo-resistive, high-temperature resistant, and corrosion resistant material. Due to their excellent thermomechanical and electromechanical (piezo-resistive) behavior with very large gauge factors, they have great potential in being used as sensing materials in harsh environment, and thus has received extensive attentions in recent years. A better understanding of their holistic thermomechanical and electromechanical properties is crucial to the improvement of both the material and corresponding sensor designs. However, there has been a lack of customized, low-cost, and automatic machine that allows researchers to study the complex properties of PDCs. In this paper, an automated platform is designed to study the electromechanical and thermomechanical properties of newly developed PDCs. Featured with automatic temperature control and pressure control capabilities, the platform is able to apply load smoothly from 0 N to 220 N, and add heat from 0 to 250°C.

Most flow visualizations and flow measurements to understand particle mobility in porous media are typically performed in transparent microfluidic devices (micro-models) with 2D pore-throat networks. Nano-particle mobility studies to date have been limited to micro-models made of transparent thermoplastic or silicone-based materials. In an effort to fabricate materials close to reservoir rock, ceramic micro-model has been designed and micro fabricated by our group to study nano-particle transport in rock-based ceramic micro-model. A Confocal Micro-Particle Image Velocimetry (C-μPIV) technique augmented with associated post processing algorithms [1] is used in obtaining 3D distributions of nano-particle velocity and concentration at selected locations of the ceramic micro-model. Furthermore, a novel in-situ, nondestructive method of measuring 3D geometry of non-transparent ceramic micro-model is described and validated. The particle experiment uses 860 nm fluorescence labeled polystyrene neutrally buoyant, and electrically neutral nano-particles. The data was acquired using confocal laser-scanning microscope to quantify 3D particle transport at selected observation locations. In addition, fluorescence microscope was used to measure in-situ geometry of porous media. Results of detailed 3D measurements of nano-particle velocity and particle concentration from experiment conducted at a constant flow rate of 30 nL/min in the rock-based micro-model are presented and discussed. Particle velocities range from 0 to 20.93 μm/sec in magnitude, and average concentration range from 6.02 × 10 3 to 6.79 × 10 3 particles at inlet channel while velocities range from 0 to 73.63 μm/sec and concentration range from 4.9 × 10 1 to 1.45 × 10 3 particles at selected observation locations of the ceramic micro-model. 3D velocity fields at selected locations also indicate that mean velocity closer to the top wall is comparatively higher than bottom wall, because of higher planar porosity and smooth pathway for the nano-particles closer to the top wall. The three dimensional micro-model geometry reconstructed from the fluorescence data can be used to conduct numerical simulations of the flow in the as-tested micro-model for future comparisons to experimental results after incorporating particle transport and particle-wall interaction models.

Thermal protection of components such as turbine blades is often done with thermal barrier coatings which are typically ceramic materials. Methods to manufacture ceramic coatings are being developed to create microstructures that optimize thermal protection without degrading mechanical properties of the coating. The coating requires sufficient mechanical properties to remain in place during loads associated with the operation of the component. The work presented in this paper is part of a broader effort that focuses on novel processing techniques. A fabrication method of interest is the inclusion of spherical micron-sized pores to scatter photons at high temperatures along with nano-sized grains to scatter phonons. Pores are sized and distributed so that mechanical strength is maintained. In the current work, yttria-stabilized zirconia (YSZ) is modeled. Three-dimensional microstructures representing YSZ are computationally generated. The defect sizes and orientations are generated to match an experimentally observed distribution. The defects are either randomly or regularly placed in the microstructural models. Stress-displacement analysis is used to determine effective bulk material properties. Comparisons are made to prior two-dimensional work and to experimental measurements available in the literature as appropriate. The influences that defect distributions and three dimensional effects have on the effective bulk material properties are quantified. This work is a preliminary step toward understanding the impacts that micron sized pores, voids and cracks have on thermal and mechanical characteristics. The goal is to facilitate optimizing the microstructure for thermal protection and strength retention.

Particle-reinforced metal matrix composites (pMMC) such as silicon carbide particle reinforced aluminum alloys (SiCp/Al) require special cutting tools due to the high hardness and abrasive properties of the ceramic particles. Diamond coated cutting tools are ideal for machining this type of pMMC. Previous research studies focus on the machinability of pMMCs with low ceramic content. The aim of this research is to determine the optimal cutting parameters for machining SiCp/Al material containing high silicon carbide particle reinforcement (>25%). Material removal rate (MRR) was used to determine the optimal cutting parameters with the tool wear and surface roughness as constraints. Cutting speed, feed rate, and depth of cut were used as design parameters for the design of experiment. High burr formation and cutting forces were observed during the experiments. Experimental milling tests are conducted using CVD diamond coated end mills and non-diamond tungsten carbide end mills. It was found that low tool rotation speeds, feed rates and depths of cut are necessary to achieve smoother surface finishes of Ra < 1 μm. A high MRR to low tool wear and surface roughness ratio was obtainable at a tool rotation speed of 6500 r/min, feed rate of 762 mm/min, and depth of cut of 3 mm. Results showed that a smooth surface roughness of the workpiece material was achieved with non-diamond tungsten carbide end mills, however, this was at the expense of extreme tool wear and high burr formation. An endurance test was run to test for complete tool failure.

In orthopedics, the current internal fixations often use screws or intramedullary rods that obstruct bone material. In this paper, an internal implant was modelled as a hollow cylindrical sector made of a functionally graded material (FGM), which will hold bone in place with less obstruction of bone surface. Functionally graded implant was considered as an inhomogeneous composite structure, with continuously compositional variation from a ceramic at the outer diameter to a metal at the inner diameter. The buckling behavior of the implant was numerically analyzed using a finite element analysis software (ANSYS), and the structural stability of the implant was assessed. The buckling critical loads were calculated for different fixation lengths, cross sectional areas, and different sector angles. These critical loads were then compared with the critical loads of an FGM hollow cylinder with the same cross sectional area. Results showed that the critical load of the hollow cylindrical sector was ∼ 63%, ∼ 70%, and ∼ 73% of the hollow cylinder for different fixation lengths, cross sectional areas, and sector angles, respectively. Further investigations are warranted to study the relation between the composition profile and the implant stability, which can lead to batter internal fixation solutions.

Diesel exhaust particulate matter (PM) is deadly to humans, animals and plants so the future of diesel engine is uncertain. Alternative powered vehicles have major limitations and costly. Recent developments to limit PM emissions have significant disadvantages to the point where they cannot be considered to be reliable long term technical and economical solutions. Electrostatic filtration could be used together with existing filters or as a standalone system. The most popular method of decreasing PM emissions is by the use of ceramic diesel particulate filters which is not efficient at filtering ultrafine particulates. Electrostatic filtration is a promising approach which can capture ultrafine particulates which could be used in conjunction with ceramic DPFs, metallic flow through filters (FTF) or, ideally as a standalone system. Development of prototype electrostatic diesel particulate filtration systems (EDPS) requires reliable testing. Prototyping needs quick, repeatable and affordable results to validate theories and a solution had to be developed. This paper presents the development of the EDPS prototype testing procedures and equipment with preliminary test results. By repurposing proven test equipment for the use of exhaust sampling, a test rig and a repeatable procedure for testing prototype filters were developed with low initial and ongoing costs.