bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of a Telemanufacturing Test Bed
Authors: Abdel-Malek Layek , Batra Vikram
Published: December 2021

A Telemanufacturing facility has been developed to test virtual manufacturing concepts across the Internet. The essence of this research is a web site/service provider to aid manufacturers, especially small and medium size, in the different production functions of concern. The web site capitalizes on the advances in virtual reality technologies to enable enterprises to gain flexibility and competitiveness. Through this web site companies/users will be able to access a variety of services available within this facility. This web site initially will act as a test bed and a resource center for enterprises to base design and manufacturing decisions as well as utilize technologies available globally. The test bed currently incorporates three facilities, Rapid Prototyping, make or buy decision support system, and manufacturing cell development. Using this facility it will be possible to evaluate the functioning of the Telemanufacturing infrastructure and also highlight the problems and deficiencies associated with the system.
Interactive Product Simulation Environment for Assessing Assembly and Maintainability Tasks
Authors: Fernando Terrence , Wimalaratne Prasad , Tan Kevin , Murray Norman
Published: December 2021

This paper presents the design and implementation of an interactive product simulation environment for supporting interactive assembly and maintenance tasks. The system architecture of the constraint-based virtual environment is based on the integration of components such as OpenGL Optimizer, Parasolid geometric kernel, a Constraint Engine, an Assembly Relationship Graph (ARG) and a task model. The approach presented in this paper is based on pure geometric constraints. Techniques such as automatic constraint recognition, constraint satisfaction, constraint management and constrained motion are employed to support interactive assembly operations and realistic behaviour of assembly parts. The user inputs are handled using a task model based on Augmented Transition Networks (ATN). The current system has been evaluated using two industrial case studies.
Analyzing Industrial Furnace Efficiency Using Comparative Visualization in a Virtual Reality Environment
Authors: Freitag Lori , Urness Tim
Published: December 2021

We describe an interactive toolkit used to perform comparative analysis of two or more data sets arising from numerical simulations. Several techniques have been incorporated into this toolkit, including (1) successive visualization of individual data sets, (2) data comparison techniques such as computation and visualization of the differences between data sets, and (3) image comparison methods such as scalar field height profiles plotted in a common coordinate system. We describe each technique in detail and show example usage in an industrial application aimed at designing an efficient, low-NOx burner for industrial furnaces. Critical insights are obtained by interactively adjusted color maps, data culling, and data manipulation. New paradigms for scaling small values in the data comparison technique are described. The display device used for this application was the CAVE virtual reality theater, and we describe the user interface to the visualization toolkit and the benefits of immersive 3D visualization for comparative analysis.
Effect of Large Structural Perturbations on Response of Structural-Acoustic Systems
Authors: Hahn Steven R. , Ferri Aldo A.
Published: December 2021

Due to high sensitivity, first-order perturbation analysis of structural-acoustic systems can be inaccurate for large perturbations. Using high-order derivatives to create a Taylor series approximation for the perturbed solution can result in slow convergence or even divergence. A rational polynomial or Padé approximation may overcome the poor convergence of the Taylor series by canceling out the poles causing the poor convergence. In this study, a finite element framework is used to describe the structural-acoustic system. External radiation and scattering problems are accommodated by truncating the infinite fluid region using exponential decay infinite elements. Changes to a nominal model are introduced through a structural perturbation to the nominal structural stiffness and/or mass matrices. An efficient method for calculating the solution derivatives with respect to the structural perturbation is presented. A Taylor series expansion is constructed using the derivative information and the convergence criteria for the series is examined. The local solution and derivatives are then used to construct a Padé approximation. The method is illustrated by considering what effect the addition of a rib stiffener to a plate in a rigid baffle has on the scattering of a plane wave. The approximation is shown to be quite accurate for large perturbations even when there are one or more nearby poles and the Taylor series fails to converge.
Acoustic Radiation by Point- or Line-Excited Laminated Plates
Authors: Hwang Y. F. , Kim M. , Zoccola P. J.
Published: December 2021

This paper presents an elasticity theory solution for computation of acoustic radiation by a point- or line-excited fluid-loaded laminated plate, which may consist of a stack of an arbitrary number of different isotropic material layers. A one-side water-loaded three-layer sandwich plate, which consists of a hard rubber core sandwiched between two steel plates of equal thickness, was used as an example of the laminated plates. The approximated equivalent sandwich plate solutions were compared with the elasticity theory solutions. These results show that the approximated solutions are, as expected, valid only at frequencies much lower than the coincidence frequency. The numerical result also shows that, even at about one-tenth of the coincidence frequency, the approximated solutions suffer substantial error. The differences between the dry-side- and the wet-side-excited radiated fields of a single-layer uniform plate and a sandwich plate were investigated and compared, and found to be significantly different at frequencies above the coincidence frequency.
Treatment of Damping in Structural Redesign by Large Admissible Perturbations
Authors: Blouin Vincent
Published: December 2021

A method to solve redesign (inverse design) problems of complex structures with forced response amplitude constraints is developed. It is assumed that a structure is excited by harmonic external forces at a given frequency. The problem is to find optimum values of structural characteristics in order to achieve a desired level of forced response at one or several locations on the structure. The method of LargE Admissible Perturbations (LEAP) is used. Damping is shown to have an important impact on the redesign solution and must be considered in the redesign process. Two different treatments of the damping, leading to two different algorithms, are studied. In the case of structural damping, the commonly used Rayleigh formulation allows the damping matrix to be diagonalized by use of the real mode shapes of the undamped structure. This leads to the derivation of an exact perturbation equation with no loss of accuracy. When damping cannot be approximated by the Rayleigh model, the damping matrix must be treated externally and the perturbation equation is solved by means of an iterative process introduced into the redesign algorithm. The two algorithms are compared in terms of accuracy and limitations.
Design Optimization Process for Minimizing High Frequency Vibration Based on an Energy Finite Element Formulation
Authors: Borlase George , Vlahopoulos Nickolas
Published: December 2021

The Energy Finite Element Analysis (EFEA) offers an alternative solution to the established Statistical Energy Analysis (SEA) for simulating the vibration of large scale structures. A brief theoretical overview and comparison of the two methods is presented first. Numerical models for a fishing boat are utilized for a comparison between the two formulations. In order to demonstrate the powerful capabilities of EFEA in the area of simulation based design, an optimization routine is integrated with an EFEA solver. The optimized distribution of damping over the hull of a vessel is computed. The formulation of the optimization process is presented. The definition of the design variables, the objective function, and the constraints is discussed. The flow chart of the optimization process, and a comparison between the initial and the optimized design are presented.
A New Design Feature to Improve the Sound and Efficiency of Automotive HVAC Centrifugal Blower Systems
Authors: Botros Monier B. , Hanna Dorothy F. , Nava Tony (J) , Lai Ming-Chia
Published: December 2021

A new apparatus is developed to control the airflow field at the inlet of a centrifugal blower system. The new apparatus has desirable effects on the flow and noise performance of an HVAC air-handling system. The apparatus design parameters are defined, and are investigated using the design-of-experiments techniques. Experimental airflow and sound pressure levels data are used to screen and evaluate the apparatus design parameters. The effects of two parameters and their interaction on the overall sound pressure levels and discrete tones, sound quality, are defined to aid in optimizing the design.

The apparatus controls the flow field to increase the effectiveness of the blower fan, and to minimize the energy losses and air-rush noise. Its effect on the air velocity in the radial direction of a centrifugal fan is investigated by Laser Doppler velocity measurements (LDV). Other relationships with the centrifugal fan design parameters are described and illustrated by LDV and computational fluid dynamic (CFD) analysis.

The advantages of the apparatus include the reduction of air-handling system SPL by 1–3dBA (2–6%) and power consumption by (7–15%) through energy conservation, with minimal change in the system airflow rate.
Prediction of Automotive Hydrobushing Resonant Frequency
Authors: Lu Min , Ari-Gur Judah , Garety John
Published: December 2021

The success of hydromounts in vehicle vibration isolation during the past decade and a half has stimulated automotive engineers to apply the similar mechanism to bushing design. A typical conventional bushing is comprised of a rubber section enclosed by an inner and an outer metal, while a bushing filled with internal fluid is called a hydrobushing. Based on the fact that the fluid inside the hydrobushing generates the majority of the damping, the mathematical model of the hydrobushing used in this paper neglects the rubber damping effect to the system. The equations of fluid motion and conservation and system equilibrium equation determine its resonant frequency. The conclusion is that the resonant frequency is proportional to the ratio of the cross sectional area of the inertia track to the equivalent piston area and the square root of volumetric stiffness; and it is inversely proportional to the square root of the mass of the fluid in the inertia track. The predicted resonant frequency correlates well with the tested results.
Wave Reflection/Transmission Analysis of Thick Multi-Layered Structures Using the Numerical Truncation Approximation for the Transfer Matrix Technique
Authors: Balasubramaniam Krishnan
Published: December 2021

In this paper, the authors describe a numerical truncation technique for handling the numerical instability problems associated with the utilization of the transfer matrix method. This, rather simplistic modification to the numerical coding extends the transfer matrix method to a wide range of applications.
Automatic Procedure for Automating the Analyzer Window Setting for Transient Vibration Data Capture
Authors: Ratcliffe Colin P. , Crane Roger M.
Published: December 2021

When conducting experimental vibration tests on composite structures, one of the most important settings in the spectrum analyzer is the window function. This setting effects the performance of the Fourier analyzer, and can change the observed energy dissipation of the structure. For impact excitation techniques the window used for transient response signals is typically an exponential function. Traditionally, the window setting is chosen by what “looks right.” Too little windowing introduces errors during the Fourier transforms; too much degrades the signal. This paper presents an automatic procedure for optimizing the exponential window function when measuring transient, decaying signals. Initially, the natural attenuation of a signal is automatically determined, and this attenuation is then used to determine the optimum window parameters. The theory is developed for a single-degree-of-freedom system and demonstrated for theoretical and experimental multi-modal structures with poor signal-to-noise ratios. In all cases it is shown that the computationally inexpensive optimization procedure is highly satisfactory. There is also a side benefit in that almost identical numerical procedures can be used to automate the logarithmic decrement technique of estimating structural damping.
Cochlear-Based Transducer Designs
Authors: Grosh Karl , Dodson John M.
Published: December 2021

The design concept of transducers based on analogies with the structure-function relations of models of the mammalian cochlea is presented.
Numerical Solution of the Equations Governing the Steady State of a Thin Cylindrical Web Supported by an Air Cushion
Authors: Müftü Sinan
Published: December 2021

The numerical method used to solve the coupled nonlinear, partial differential equations (PDEs) representing the interaction between a thin, flexible, cylindrical web and an air cushion at steady state is analyzed. The web deflections are modeled by a cylindrical shell theory that allows moderately large deflections. The airflow is modeled in two-dimensions with a modified form of the Navier-Stokes and mass balance equations that have non-linear source terms. The coupled fluid/structure system is solved numerically in a stacked iteration scheme: The fluid equations are solved using pseudo-compressibility method with artificial viscosity; and the web equations are solved with a modified Newton-Raphson method. The convergence characteristics of the coupled system and the effects of the numerical parameters on the steady state solution are studied by numerical experiments.
The Sound Transmission Through a Baffled, Thin, Finite, Elastic Plate by Using Boundary Integral Equations
Authors: Kawai Yasuhito
Published: December 2021

The prediction of sound transmission through a thin elastic plate such as a window is an important problem in the field of noise control engineering. Integral equations which express sound fields in infinite half spaces which are divided off by the baffle and the elastic plate are introduced and combined with the equation of plate vibration to solve as a coupled system. The image method is used in every equation to reduce unknown functions and boundaries which should be considered. Some numerical examples are solved numerically to examine the method.
Modification of Resonance-Induced Sound by the Configuration of a Slotted Tube
Authors: Seto Kunisato , Lee Dong-Hoon , Xu Zhi Xiang
Published: December 2021

A slotted tube is a device to reduce flow-induced noise. In order to understand the noise reduction mechanism of the tube, an experiment has been systematically performed. Noise measurements have been carried out for a variety of slot dimensions such as the length, the width, the thickness and the number of slots. In the case of a significantly long slot, a discrete tone is observed under comparatively lower pressure conditions. Three mechanisms of sound generation concerning the slotted tube have been clarified.
Acoustic Radiation Models of Brake Systems From Stationary LDV Measurements
Authors: McDaniel J. Gregory , Moore James , Chen Shih-Emn , Clarke Cory L.
Published: December 2021

This paper presents a study of the acoustic radiation from a stationary brake system that was conducted in order to better understand the acoustic radiation from squealing brake systems. A large class of squeal mechanisms are associated with the resonant behavior of an operating brake system. In this work, an analysis is presented that equates the natural frequencies and modes of a mechanically-excited stationary brake system to those of an operating brake system. The equivalence allows one to conduct experiments on stationary brake systems in order to gain insight into the acoustic radiation mechanisms of squealing systems, which is a substantial convenience given the difficulty of artificially inducing squeal. The methodology is applied to scanning LDV measurements of the normal velocity of a shaker-excited stationary brake system. Acoustic radiation efficiencies and intensities of the modes were computed by importing the experimentally measured velocities into a BEM software package. These efficiencies approach unity at a coincidence frequency defined by comparing acoustic wavelengths to the wavelengths of flexural waves that propagate circumferentially around the rotor. For the particular system tested, this remarkably high radiation efficiency occurred at frequencies above 2–3 kHz.
Asymptotic and Exact Radiation Boundary Conditions for Time-Dependent Scattering
Authors: Thompson Lonny L. , Huan Runnong
Published: December 2021

Asymptotic and exact local radiation boundary conditions first derived by Hagstrom and Hariharan are reformulated as an auxiliary Cauchy problem for linear first-order systems of ordinary equations on the boundary for each harmonic on a circle or sphere in two- or three-dimensions, respectively. With this reformulation, the resulting radiation boundary condition involves first-order derivatives only and can be computed efficiently and concurrently with standard semi-discrete finite element methods for the near-field solution without changing the banded/sparse structure of the finite element equations. In 3D, with the number of equations in the Cauchy problem equal to the mode number, this reformulation is exact. If fewer equations are used, then the boundary conditions form uniform asymptotic approximations to the exact condition. Furthermore, using this approach, we formulate accurate radiation boundary conditions for the two-dimensional unbounded problem on a circle. Numerical studies of time-dependent radiation and scattering are performed to assess the accuracy and convergence properties of the boundary conditions when implemented in the finite element method. The results demonstrate that the new formulation has dramatically improved accuracy and efficiency for time domain simulations compared to standard boundary treatments.
Influence of Support Compliance and Residual Stress on the Shape of Doubly-Supported Surface-Micromachined Beams
Authors: Kobrinsky Mauro J. , Deutsch Erik R. , Senturia Stephen D.
Published: December 2021

Doubly-supported surface-micromachined beams are increasingly used to study the mechanical properties of thin films. Residual stresses in the beams cause significant vertical deflections, which affect the performance of these devices. We present here both experimental results for doubly-supported polysilicon surface-micromachined beams, and an elastic model of the devices that takes into account the compliance of the supports and the geometrical non-linear dependence of the vertical deflections on the stress in the beam. An elastic one-dimensional model was used for the beams, and the response of the supports to forces and moments was obtained using Finite Element Method simulations. The model explains a previously observed gradual increase of the maximum vertical deflections of the beams with increasing length at a given constant residual stress, and, in agreement with experimental observations, predicts two stable states for compressively stressed beams: one with the beam bent up, the other down.
Three-Dimensional Modeling of Solder Shape for the Design of Solder Self-Assembled Micro-Electro-Mechanical Systems
Authors: Kladitis Paul E. , Harsh Kevin F. , Bright Victor M. , Lee Y. C.
Published: December 2021

Micro-electro-mechanical systems (MEMS) can be assembled by harnessing the surface tension of liquid solder. In order to assemble the MEMS to precise positions, the shape of the solder, of a given volume, must be known. This paper presents two methods of modeling the shape of solder wetted between two MEMS plates. One method accurately models the solder shape by finding the minimum surface energy shape. A second, less accurate but faster, method approximates the solder shape using simple geometric shapes. The geometric shape model can be trained to be just as accurate as the minimum surface energy model.
Localized Deposition of Polysilicon for MEMS Post-Fabrication Processing
Authors: Joachim Daphne , Lin Liwei
Published: December 2021

In this paper, the localized deposition of polysilicon is demonstrated on suspended and attached microbeams. The microbeams are 1, 2 and 5μm wide; 0.5, 1.5 and 2μm thick; and 50 and 100 μm long. Polysilicon is deposited by thermal decomposition of silane gas on the electrically-heated structures. The peak temperature of each microbeam is estimated using finite element analysis and an electro-thermal analysis is discussed. The deposited silicon is amorphous or polycrystalline, depending on the process conditions. The deposition rates are much higher than those of conventional LPCVD polysilicon. Localized polysilicon deposition is useful in MEMS post-fabrication processes such as tuning resonators and sealing packages.
Squeeze Film Damping Effects in a Micromachined Tunneling Accelerometer
Authors: da Silva Mark G. , Greiner Ken , Liu Cheng-Hsien , Kenny Thomas W. , Gilbert John R.
Published: December 2021

Attempts at predicting the squeeze film damping (SQFD) effects in MEMS devices have by and large been restricted to the following approaches; analytic [1] or numerical [3–5] modeling of the Reynolds equation, or numerical solutions of incompressible Navier-Stokes (NS) [6] and correcting the Reynolds or incompressible NS for the effects of high Knudsen number [3, 7]. There are key difficulties with these approaches that render them unsuitable or unacceptable for realistic design problems. Recently the development of a hybrid technique called Navier-Stokes-Reynolds (NSR) [8] has shown some promise in addressing some of the key difficulties in previous approaches. In this work we extend the method to a class of devices characterized by nonuniform gaps (e.g. tilting mirrors [2], accelerometers etc.). The micromachined high precision tunneling accelerometer designed at the SMSSL (Stanford University [9]) is one such device. A comparison of the experiments and predictions show quite good agreement over the operating regime of the device.
Thermal Design and Batch Fabrication of Cantilever Probes for Scanning Thermal Microscopy
Authors: Shi Li , Kwon Ohmyoung , Wu Guanghua , Majumdar Arunava
Published: December 2021

Scanning thermal microscopy (SThM) has enabled direct observation of thermal phenomena at the nanometer scale. The superior spatial resolution makes SThM attractive for thermally probing electronic and optoelectronic devices as well as nano-structures. In the past, lack of thermal design of SThM probes led to inaccuracy and artifacts in the thermal images. Based on the knowledge of various tip-sample heat transfer mechanisms, this paper presents a one-dimensional model to estimate the temperature distribution in the probe tip. Based on the model, new thermal probes that have SiO2 tips, SiNx cantilevers, and Pt-Cr thermocouple junctions at the tip ends have been designed and fabricated. The fabrication process consists of only wafer-stage processing steps with more than 100 probes fabricated on a single wafer. The thermal probes have been successfully used for topographical imaging and to measure the intensity profile of a focused laser spot.
A Thermal Cycler Fabricated With Low Temperature, Co-Fired Ceramic Tapes
Authors: Zhong Jihua , Yi Mingqiang , Bau Haim H.
Published: December 2021

A thermal cycler fabricated with low temperature, co-fired, ceramic tapes is described. The monolithic device consisted of a flow conduit, a resistor (Joule) heater, a thermistor, and conductors. A microprocessor was used to control the device’s temperature according to a pre-programmed temperature protocol. The device’s thermal performance was modeled, and the theoretical predictions were compared with experimental observations. As an example of an application, the device was used to carry out a polymerase chain reaction in which a non detectable concentration of a DNA segment was sufficiently amplified so as to enable separation and detection by electrophoresis.
Modeling, Simulation and Testing of Non-Linear Resonance Behavior in MEMS Torsional Mirrors With Mechanical-Electrostatic Coupling
Authors: Rensing Noa M. , Dodson Stuart , Adams George G. , Zavracky Paul M. , McClelland Robert W. , Lemoncelli Anthony
Published: December 2021

In order to obtain high angular displacement, MEMS micromirrors can be driven at resonance. This paper presents experimental and modeling results on the displacement as a function of drive amplitude for standard nickel and nanocrystalline nickel springs in two geometries. Although the resonance frequency of the torsional MEMS oscillators is adequately predicted by a linear mechanical model of the system, prediction of the angular motion at the design displacements requires attention to non-linear effects. Thus a model is proposed which incorporates non-linear effects due to the displacement of the mirror-spring system from its equilibrium position.
Silicon Microrelays With Optimized Electrostatic Actuator
Authors: Schimkat Joachim
Published: December 2021

The design of the electrostatic moving wedge actuator for silicon microrelays was improved towards higher contact force and lower driving voltage. Additional degrees of freedom were included in the design, providing capabilities for tuning the switching characteristics according to the contact material requirements. The relationship of the new geometric parameters and the switching characteristics was determined by simulation. Optimized silicon microrelays exhibit contact forces up to 0.9 mN at nominal voltages of 12 V or 24 V. Further outstanding qualities are the high shock resistance and the nearly neglectable driving power. The commercial application of silicon microrelays will focus on small current applications.
The Fabrication of Micro Mold Inserts Using Thick Film Resist Approach
Authors: Yu Huinan , Ganser Dale , Gehoski Kathleen A. , Mancini David , Rhine David , Smekal Thomas , Grodzinski Piotr
Published: December 2021

This paper reports the use of dry film resists and two spunon thick film photoresist (AZ9260 and SU8) as template in the fabrication of micro mold inserts for disposable plastic microfluidic devices.
Development of Planar Microfluidic Systems Using Conventional and Low Temperature Assembling Schemes for Components
Authors: Okulan Nihat , Bhansali Shekhar , Han Arum , Dharmatilleke Saman , Choi Jin-Woo , Patel Manoj , Oh Kwang W. , Henderson H. Thurman , Ahn Chong H.
Published: December 2021

This center is currently working on the development of a remotely accessible generic microfluidic system (“lab on a chip”) for biological and biochemical analysis, based on electrochemical detection techniques. Modular microfluidic components, including micro reservoirs, microvalves, micropumps, filterless magnetic particle separators, biosensors and flowsensors, were fabricated and tested, and integrated on a system motherboard. Other air-to-liquid measurand concentrators and integrated sieve/filters are being explored in related efforts. The fabrication of these microfluidic components and the utilization of wax for low temperature assembly and even bonding is discussed.
Investigation of Micro-Scale Materials Behavior With MEMS
Authors: Haque M. A. , Saif M. T. A.
Published: December 2021

This study presents a methodology for uniaxial tension testing of both micron and sub-micron scale specimens using MEMS devices. The methodology allows free standing, single or multi-layered specimens to be fabricated separately from the MEMS device. The MEMS device is a comb drive actuator which can be calibrated for force measurement. Materials behavior can be observed in-situ in analytical chambers such as SEM and TEM and under different environmental conditions. The methodology is demonstrated with the testing of a free standing polymer and an Aluminum specimen with thickness 1.3 microns and 110 nanometers respectively. Significant deviation in materials behavior is observed between bulk and micro-scale.
Characteristics of 12 μm Thick Polysilicon for an Optically-Sensed Accelerometer
Authors: Chen Y. H. , Kudrle T. D. , Tien N. C.
Published: December 2021

A low-stress thick polysilicon surface micromachining process has been successfully developed. An accelerometer composed of a 12μm thick polysilicon layer and an integrated photo diode on the substrate was fabricated and tested demonstrating the functionality of the process. The polysilicon film has an estimated stress of 0.6 MPa (tensile). This new technology combines some of the advantages of high-aspect-ratio bulk-micromachining such as large capacitance and high out-of-plane stiffness, with the proven advantages typically found for surface micromachining such as the formation of multi-level elements.

In this paper, we first present the optimized process flow, which provides the low-stress thick polysilicon film. Then, the important characteristics of thick polysilicon films such as internal stress, stress gradient and surface roughness are discussed. Testing of the integrated photodiode was performed. Finally, the initial testing results for the accelerometer are presented to demonstrate the success of this newly developed technology.
Design, Analysis, Fabrication, and Testing of a MEMS Flow Sensor
Authors: Barnes Terrence G. , Truong Thieu Q. , Lu Xiaoqing , McGruer Nicol E. , Adams George G.
Published: December 2021

A new type of MEMS flow sensor has been designed, analyzed, fabricated, and tested. This sensor consists of a surface micromachined switch with a complex cantilever shape. A portion of the sensor is bent at a right angle to the substrate and to the flow direction. The fluid flow produces a pressure on the sensor; sufficient pressure causes the switch to close at the designed flow rate. These flow sensors have been developed for a large multi-university project for the design and construction of a biomimetic underwater lobster robot to be used to search for and destroy mines. However, we envision a variety of other uses for these flow sensors, including biomedical applications such as blood flow measurement.

The fabrication process is based on the Northeastern University Metal Micromachining (NUMEM) technology [1]. The NUMEM process has been used to fabricate various surface micromachined metallic structures such as microrelays, microinterferometers, micromirrors, and microaccelerometers.

The analysis of these devices consists of using incompressible fluid mechanics to determine the pressure acting on the sensor and beam theory to model the resulting deflection of the switch. The first set of flow sensors was designed to close at flow velocities of 0.5, 1.0, 3.4, and 5.4 m/s. The area of the paddle, which lies in the flow, is varied in order to obtain sensors that close at different flow rates. The results of testing agree well with the analytical predictions. Although these flow sensors are unidirectional, an array of four sensors at each point can be used to determine the flow velocity and direction.
Characterization of Shear Stress Field Induced by Obliquely Impinging Airjets
Authors: Biegelsen David K. , Panides Elias , Swartz Lars E. , Jackson Warren B. , Berlin Andrew A.
Published: December 2021

Air jets obliquely incident on the surface of an object can produce sizable, localized, tangential forces. A MEMS-like system with tilted jets oriented in the four cardinal directions has been fabricated using extensions to printed circuit board technology. In this paper the fluid dynamic characteristics of the jets are reported. Jets approximately 1 mm in diameter are driven by pressure drops of ∼0.5 kPa. The shear stresses produced on an opposing wall (simulating a levitated object) are mapped both physically and in computational simulation. The shear stress distributions and the variations with pressure drop, channel height, jet diameter and jet tilt angle are reported.
Development of a Latching Valve for Micro-Chem-Lab™
Authors: Wong C. Channy , Adkins Douglas R. , Manginell Ronald P. , Frye-Mason Gregory C. , Hesketh Peter J. , Stanczyk Thomas
Published: December 2021

An integrated microsystem to detect traces of chemical agents (μChemLab™) is being developed at Sandia for counter-terrorism and nonproliferation applications. This microsystem has two modes of operation: liquid and gas phase detection. For the gas phase detection, we are integrating these critical components: a preconcentrator for sample collection, a gas chromatographic (GC) separator, a chemically selective flexural plate wave (FPW) array mass detector, and a latching valve onto a single chip. By fabricating these components onto a single integrated system (μChemLab™ on a chip), the advantages of reduced dead volume, lower power consumption, and smaller physical size can be realized. In this paper, the development of a latching valve will be presented.

The key design parameters for this latching valve are: a volumetric flow rate of 1 mL/min, a maximum hold-off pressure of 40 kPa (6 psi), a relatively low power, and a fast response time. These requirements have led to the design of a magnetically actuated latching relay diaphragm valve. Magnetic actuation is chosen because it can achieve sufficient force to effectively seal against back pressure and its power consumption is relatively low. The actuation time is rapid, and valve can latch in either an open or closed state. A corrugated parylene membrane is used to separate the working fluid from internal components of the valve. Corrugations in the parylene ensure that the diaphragm presents minimum resistance to the actuator for a relativley large deflection.

Two different designs and their performance of the magnetic actuation have been evaluated. The first uses a linear magnetic drive mechanism, and the second uses a relay mechanism. Preliminary results of the valve performance indicates that the required driving voltage is about 10 volts, the measured flow rate is about 50 mL/min, and it can hold off pressure of about 5 psi (34 kPa). Latest modifications of the design show excellent performance improvements.
High Fidelity and Compact Models of Synthetic Jets and Their Application in Aerodynamics and Microelectronics
Authors: Przekwas Andrzej J. , Chen Zhijian , Turowski Marek
Published: December 2021

Computational simulation of coupled unsteady fluid mechanics and electromechanical actuation of a single synthetic jet can be performed with available CFD tools. Modeling of flow physics of large arrays of synthetic jets is computationally very challenging. This paper presents two complementary computational technologies: a high-fidelity physical model of a single jet, and a reduced (compact) model of the jet for modeling large array of synthetic jets. The high-fidelity model first has been validated against experimental data and then used to calibrate the compact model.

The paper presents computational evaluation of accuracy and range of applicability of compact models and demonstrates them on multi-dimensional simulations of aerodynamic flow control and on electronics cooling applications.
An Actively Controlled Micromixer
Authors: Volpert Marion , Meinhart Carl D. , Mezic Igor , Dahleh Mohammed
Published: December 2021

An active mixing strategy has been developed to enhance mixing of two fluids through a microchannel. Mixing is enhanced when the flow through the main channel of the mixer is perturbed by three sets of secondary flow channels. Numerical solutions of the flow through the mixer are calculated by simulating the full Navier-Stokes equation, the Stokes equation, and a simple analytical model based upon the superposition of elementary velocity profiles. The analytical model agrees qualitatively with Navier-Stokes and Stokes solutions for Reynolds numbers, Re = 5. A mixing coefficient is developed to quantitatively evaluate mixing efficiency for various flow configurations. The results indicate enhanced mixing for two possible flow configurations.
Dielectrophoretic Manipulation of Particles for Use in Microfluidic Devices
Authors: Miles Robin , Belgrader Phil , Bettencourt Kerry , Hamilton Julie , Nasarabadi Shanavaz
Published: December 2021

Amplification and hybridization of DNA are commonly used techniques to verify the presence of a specific DNA sequence in a test sample. Automatic sample handling to concentrate and purify a sample prior to amplification is desirable to increase the sensitivity of the test, to reduce the possibility of sample contamination such as inhibitors and to reduce reagent use. This paper explores the use of the dielectrophoretic force to manipulate DNA, Bacillus globigii spores and Erwinia herbicola bacteria to provide both concentration and purification as part of the sample handling functions in biological assay equipment. It was found that typical microfabricated structures with electrode gaps of 30μm operating at 5V could achieve very effective concentration of these particles.
Near-Field Electromagnetic Shielding Effect of On-Chip Electroplated Copper Layers
Authors: Kang Tae Goo , Cho Young-Ho
Published: December 2021

An experimental investigation on the near field electromagnetic loss of thin copper layers has been presented for applications to multi-chip microsystems with on-chip electromagnetic protection. Copper layers in the thickness range of 0.2 μm∼200μm have been electroplated on the silicon substrates. A pair of microwave transceivers has been fabricated using the 3.5mm × 3.5mm nickel microloop antennas, electroformed on the silicon substrates. Electromagnetic radiation loss has been measured for the copper layers placed between the microloop transceivers, resulting in the electromagnetic shield effectiveness of 10dB∼40dB for the wave frequency range of 100MHz ∼ 1GHz. The 0.2μm-thick copper layer provides a shield loss of 20dB at the frequencies higher than 300MHz, whereas showing a predominant decrease of shield loss to 10dB level at lower frequencies. No substantial increase of the shield effectiveness has been found for the copper shield layers thicker than 2μm.
The Electro-Thermally Driven Micro Membrane Actuators With Two-Way Deflection
Authors: Hsu Chen Peng , Hsu Wensyang
Published: December 2021

This paper presents design, simulation, fabrication, and testing of two types of two-way micro membrane actuators able to deflect in both upward and downward directions with continuous deflections. Both actuators are electro-thermally driven, comprising of aluminum and silicon dioxide served as the main materials of top and bottom layer. In testing, the driving voltage is less than 4 volts and the power consumption is less than 400 mW. The upward deflections of the membrane actuators for the first design and the second design are 50 μm and 40 μm respectively, and both designs can achieve downward deflections of 15 μm. However, the characteristic of operation for each design is different.
Thermal Conductivity of Porous Silicon Layers for MEMS
Authors: Srinivasan Uma , Breh Peter , Asheghi Mehdi , Touzelbaev Maxat , Goodson Kenneth E.
Published: December 2021

Porous silicon is a promising material for MEMS because of its unique electrical, thermal, optical, and absorptive properties. This work measures the thermal conductivity of a silicon layer with 40 percent porosity at temperatures between 20 and 300 K using Joule heating and electrical-resistance thermometry. The room-temperature thermal conductivity is 0.43 Wm−1K−1, which is almost three orders of magnitude less than the value for single-crystal silicon. The data are interpreted using a new model based on electron microscopy, which shows a sponge-like morphology with embedded crystalline regions. The model separately treats the contributions of the sponge-like material, in which the solid regions are assumed to be amorphous silicon, and the larger crystallites, in which the conductivity is reduced by boundary scattering. The present work is particularly useful for MEMS based on silicon with porosity below 50 percent, for which no thermal conductivity data were previously available.
Biological Force Measurements Using Micromachined Cantilevers
Authors: Liang Y. , Welch J. N. , Rudnitsky R. G. , Kenny T. W.
Published: December 2021

There are many interesting biological systems that utilize small mechanical forces to achieve functionality. Protein folding, ligand-receptor binding, cellular adhesion, and others all rely on picoNewton sized mechanical forces. In many of these examples, the fundamental character of the interaction remains controversial. In this paper, we describe work in progress to develop micromechanical force-measuring instruments suitable for measurements of these small biologically derived forces.
A Simple Silicon Based Nitric Oxide Sensor
Authors: Bariatto Marcelo , Furlan Rogerio , Arakai Koiti , Santiago-Aviles Jorge J.
Published: December 2021

Nitric oxide (NO) is known to mediate many beneficial physiology processes, motivating its detection in vivo as well as in vitro. Electrochemical detection provides the required cellular level determination of NO among several other techniques.

In this work, electrochemical micro-sensors for both types of detection, in vivo and in vitro, were developed, exploring the silicon planar technology, which presents high yield and reliability and also permits batch fabrication.

The developed in vitro sensor features eight detection sites (10 μm × 10 μm microelectrodes), for determination of nitric oxide spatial distribution or multi-species analysis. Different electrochemical methods were applied to provide sensor calibration and chemical reproducibility.

For in vivo analysis, the designed structures have a needle shape (40 μm thick) and they were silicon micro-machined by using plasma etching or etch stop techniques. Different configurations were designed and implemented, containing a number of detection microelectrodes that vary from 2 to 10.

The amperometric detection of both nitric oxide and nitride (NO2−) — a molecule that causes an interference — were investigated by using the in vitro micro-sensor configuration. The need of a cationic exchanger (Nafion) was demonstrated in order to provide selectivity to NO for low concentrations. Also, the developed sensor has a sensitivity of 500 A/M.cm2 and a detection limit of 10 μM.
Adapting an Articulated Vehicle to the Drivers
Authors: Yang Xiaobo , Rakheja Subhash , Stiharu Ion
Published: December 2021

A yaw plane model with limited roll DOF of a five-axle tractor semitrailer is developed to study the open-loop directional dynamics of the vehicle. A comprehensive driver model incorporating path preview, low and high frequency compensatory gains and time delays, and prediction of tractor lateral acceleration, articulation rate of the combination and the trailer sprung mass roll angle is developed and integrated with the vehicle model. The coupled driver-vehicle model is analyzed to explore the performance potentials of the vehicle design adapted for control limits of the driver. The data reported in the published studies are reviewed to identify range of control limits of the drivers in terms of preview distance, reaction time and compensatory gain. A comprehensive performance index including the path tracking, vehicle dynamic response characteristics and the driver’s steering effort is formulated and minimized using Gauss-Newton method to derive the desirable ranges of the vehicle parameters, including geometric, inertial, suspension, tire and the fifth wheel. The results of the study revealed that a driver with higher skill can easily adapt the vehicle with large size, soft suspension and relative over-steer nature. The adaptability of the vehicle is further examined for different drivers with varying skills. It is concluded that the adaptability and thus the directional performance of the vehicle can be enhanced through variations in the weights and dimensions, and suspension, tire and the fifth wheel properties. The results further show that the driver-adapted vehicle yields up to 33% reduction in the steering effort demand posed on the driver, while the roll angle and yaw rate response decrease by up to 40%.
Fourier Series-Based Neural Networks for Vehicle System Identification
Authors: Haque Imtiaz , Schuller Juergen
Published: December 2021

The use of neural networks in system identification is an emerging field. Neural networks have become popular in recent years as a means to identify linear and non-linear systems whose characteristics are unknown. The success of sigmoidal networks in parameter identification has been limited. However, harmonic activation-based neural networks, recent arrivals in the field of neural networks, have shown excellent promise in linear and non-linear system parameter identification. They have been shown to have excellent generalization capability, computational parallelism, absence of local minima, and good convergence properties. They can be used in the time and frequency domain. This paper presents the application of a special class of such networks, namely Fourier Series neural networks (FSNN) to vehicle system identification.

In this paper, the applications of the FSNNs are limited to the frequency domain. Two examples are presented. The results of the identification are based on simulation data. The first example demonstrates the transfer function identification of a two-degree-of freedom lateral dynamics model of an automobile. The second example involves transfer function identification for a quarter car model. The network set-up for such identification is described. The results of the network identification are compared with theory. The results indicate excellent prediction properties of such networks.
Spatial Multibody Modeling and Vehicle Dynamics Analysis of a High-Mobility, Heavy Cargo Transport Truck With Swing Arm Suspension
Authors: Letherwood Michael D. , Gunter David D.
Published: December 2021

This document presents the results of a computer-based dynamic performance assessment of a TATRA Truck with a swing arm suspension. A fully three dimensional TATRA model was created using a commercially available modeling and simulation methodology called Dynamic Analysis and Design Systems (DADS) (1). Limited validation was performed by comparing model predictions with video recordings of field tests (2). The model was considered accurate enough to predict various aspects of ride quality and stability performance, critical to the US Army mission needs. Performance evaluations were made by analyzing state variable time histories and high definition computer-generated animations recorded on video tape. One-to-one comparisons of the TATRA and a standard, solid-axle, heavy tactical vehicle (HTV) operating in various terrain and obstacle negotiation conditions were performed.
Dynamic Interaction Between the Manipulator and Vehicle of a Mobile Manipulator
Authors: Meghdari A. , Durali M. , Naderi D.
Published: December 2021

A manipulator mounted on a moving vehicle is called a mobile manipulator. A mobile manipulator with an appropriate suspension system can pass over uneven surfaces, thus having an infinite workspace. If the manipulator could operate while the vehicle is traveling, the efficiency concerning with the time and energy used for stopping and starting will be increased. This paper presents the kinematics and dynamic modeling of a one degree of freedom manipulator attached to a vehicle with a two degrees of freedom suspension system. The vehicle is considered to move with a constant linear speed over an uneven surface while the end effector tracks a desired trajectory in a fixed reference frame. In addition, the effects of dynamic interaction between the manipulator and vehicle (including the suspension system’s effects) have been studied. Simulation results from straight line trajectory are presented to illustrate these effects.