Daniel Stutts

Missouri University of Science and Technology | Missouri S&T · Department of Mechanical Engineering

The estimation of thermal conductivity (k) by Ångström’s method is well known and a popular alternative to the existing ASTM standards because it allows for an easier setup due to the model’s simpler boundary conditions. The shortcomings of this approach are that only two temperature locations are used, making it highly sensitive to temperature sen...

These data were acquired to estimate the parameters of a closed form solution of a one-dimensional transient convection heat diffusion PDE. The purpose was to demonstrate that the model could be used to determine the thermal conductivity. The system was tested for a wide range of thermal conductivity, 15-400 W/mK, in order to verify that the method...

This study investigates an approach to determine the thermal conductivity of a material from transient temperature data. For this study, a one-dimensional transient convection heat diffusion PDE with a closed-form solution is used to model slender test coupons. The inhomogeneous boundary condition is handled using eigenfunction expansion and Green’...

This study verifies a novel approach to determine the thermal conductivity developed by the first two authors [1] as applied to additively manufactured selective laser melted stainless steel 304L specimens having a range of 1.4 to seven percent porosity. The selective laser melting technique is highly dependent on the process parameters used, unlik...

The drillstring used in the oil and gas exploration is a complex structure due to the different forces acting on it. One of the primary sources of drillstring vibrations is the cutting forces caused by the drill bit contact with the rock formation. In some drilling applications, such as hole enlargement and underreaming, the source of the cutting a...

Excessive drill stem (DS) vibration while rotary drilling of oil and gas wells causes damages to drill bits and bottom hole assemblies (BHAs). In an attempt to mitigate DS vibrations, theoretical modeling of DS dynamics is used to predict severe vibration conditions. To construct the model, decisions have to be made on which beam theory to be used,...

Drill stem vibration may cause drilling inefficiencies and often leads to non-productive time. Drill stem vibration analysis is performed to prevent and identify RPM values that may cause damaging standing waves in the drill stem. However, different models and assumptions give different vibration results. One simplification commonly done is excludi...

Abstract: Wind loading and windborne debris (missile) impact are the two primary mechanisms that result in window glazing damage during hurricanes. Wind-borne debris is categorized into two types: small hard missiles; such as roof gravel; and large soft missiles representing lumber from wood-framed buildings. Laminated architectural glazing (LAG) m...

Abstract Building façades are vulnerable to wind and wind-borne debris during extreme weather conditions like hurricanes. Laminated glazing is widely used as window glazing material to ensure the integrity of the building interiors. Wind-borne debris has been classified as small-hard and large soft missiles representing small gravel to large wooden...

Traveling wave ultrasonic motors are driven by frictional force in the contact interface between the stator and the rotor. The operational characteristics of ultrasonic motors are determined by the contact mechanics. A quasi-analytical contact model of a ring-type traveling wave ultrasonic motor applied to the Canon autofocus lens drive system is p...

During windstorms and hurricanes, architectural glazing is subjected to wind loading and windborne debris impact. Wind-borne debris is categorized into two types. One is small hard missile like roof gravel and the other is large soft missile representing the lumber from wood-framed buildings. Laminated architectural glazing (LAG) is the commonly us...

A health monitoring approach is investigated for hydrokinetic turbine blade applications. In-service monitoring is critical due to the difficult environment for blade inspection and the cost of inspection downtime. Composite blade designs provide a medium for embedding sensors into the blades for in-situ health monitoring. The major challenge with...

A sensor to measure the stator torsional vibration due to torque ripple produced by a surface mount permanent magnet machine is first described. The sensor is relatively inexpensive and is straight forward to incorporate into a drive system. Experiments are performed to validate that the voltage produced by the sensor is linearly related to torque...

Numerous investigators have explored the factors that contribute to the high electromechanical performance of stress-biased actuators with particular attention being given to the importance of the extrinsic (domain wall translation) response mechanism. Based on the variation in lateral stress through the thickness of the piezoelectric layer within...

In this paper, the use of a piezoelectric polymer material to measure the harmonics of electromagnetic torque produced by a permanent magnet synchronous machine is described. The advantages of the polymer include low cost, durability, and flexibility. In addition, wide-bandwidth sensors are relatively easy to design and couple to drive system hardw...

Brushless DC machines with nonsinusoidal back-emf are often characterized by significant torque ripple that occurs as a result of the interaction of back-emf and stator current harmonics, as well as cogging torque. In this paper, a method of mitigating the torque ripple is described that utilizes closed-loop feedback control. Specifically, the torq...

This paper describes the design of a piezoelectric tuning-fork, dual-mode motor. The motor uses a single multilayer piezoelectric element in combination with tuning fork and shearing motion to form an actuator using a single drive signal. Finite-element analysis was used in the design of the motor, and the process is described along with the select...

This paper describes the design of a piezoelectric tuning-fork dual-mode motor. The motor uses a single multilayer piezoelectric element in combination with tuning fork and shearing motion to form an actuator using a single drive signal. Finite-element analysis was used in the design of the motor, and the process is described along with the selecti...

The design, optimization, and properties of a prototype small traveling-wave ultrasonic piezoelectric linear motor design are described. A method for optimizing the geometry of the motor to maximize its mechanical output for a given electrical input is described, as is the inherent properties of the design to maximize the motors durability and util...

The development of piezoelectric motors has spurred an interest in the vibration characteristics of plates laminated with piezoelectric materials. In particular, this paper details the study of an annular plate composed of one stainless steel lamina and either one or two piezoelectric laminae, a common configuration for piezoelectric motors. The st...

t #(t) must vanish at t = t 1 , and t = t 2 . In other words, u(t) and U(t) coincide at the end points of the interval [t 1 ,t 2 ], where t 1 , and t 2 are arbitrary. Now that we have the stage more or less set up, lets see what rules the functional F (U, U , t) must obey to render (1) extreme. We have, by definition, that the function u(t) renders...

A simple model of the effect of a concentrated radial stiffness non-uniformity in a passenger car tire is presented. The model treats the tread band of the tire as a rigid ring supported on a viscoelastic foundation. The distributed radial stiffness is lumped into equivalent horizontal (fore-and-aft) and vertical stiffnesses. The concentrated radia...

It should be noted that the examples given here have been motivated by the solution of consistent systems of equations which have an equal number of unknowns and equations. Therefore, only the analysis of square (n by n) matrices have been presented. Furthermore, only the properties of real matrices (those with real elements) have been included.

Alternative methods for orthopedic fixation can be classified into bio-absorbable and bio-incorporative methods. Bio-absorbable materials such as polyglycolic acid and polydioxanone are eliminated from the body over time while bio-incorporative materials such as ceramics and glasses, and human cortical bone eventually form part of the body. Polygly...

The pneumatic tire was modeled as a tension band on a viscoelastic foundation, an approximation proven to be valid by previous investigators. The ground contract region of the rolling tire in steady state was found by solving a two-point boundary value problem with specified radial deflections, treating the ground contact end points as unknowns. Th...

When measuring bearing forces of the tire-wheel assembly during drum tests, it was found that beyond certain speeds, the horizontal force variations or so-called fore-aft forces were larger than the force variations in the vertical direction. The explanation of this phenomenon is still somewhat an open question. One of the hypothetical models argue...

A single muscle fiber is composed of many structures called sarcomeres, the basic functional unit of the muscle that is connected in series. A sarcomere is composed of two plates facing each other called z-lines, from each of which numbers of actin and myosin filaments arise and interdigitate. Upon receiving the proper electrochemical stimulus, the...

U(t). We will now specify that the functions u(t), and (t) are of class C2. That is, they possess continuous second derivatives with respect to t. Further, let us stipulate that (t) must vanish at t = t1, and t = t2. In other words, u(t) and U(t) coincide at the end points of the interval (t1,t2), where t1, and t2 are arbitrary.

inum beam are thin enough(14 mils or 0.356 mm) that thead ditional massandsti#nesscontributedto the beam is negligible. Inad dition, since they are longandrelatively narrow, we will neglect anyind ucedstrain in they-directionperpendicular to the long axis ofthe beam. Hence, weneedonlyconsider theone-dimensional piezoelectricconstitutive equations w...

To address a common complaint from students that the undergraduate controls lecture course in mechanical engineering is too abstract, an electromechanical mini-lab was developed. The term "mini-lab" is used here to emphasize the fact that the lab augments the lecture, but does not replace a full controls lab. This mini-lab consists of a simple DC m...