bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Ballistic Impact Damage of Fiber Reinforced Plastic Laminates Bonded by Polycarbonate Facesheets
Authors: Hosur M. V. , Vaidya U. K. , Haque A. , Kulkarni M. , Kulkarni R. , Jeelani S. 
Published: December 2021

Abstract
Fiber reinforced polymer matrix composites are being increasingly used in many applications including aerospace, armored vehicle, marine and sporting industries. They provide the advantage of high specific stiffness and specific strength as compared to conventional metallic materials. However, they are well known by their vulnerability to threats like impact loading that occurs normally in the transverse direction. Hence, there is a need to improve the damage resistance in the transverse direction at minimum weight penalty. In this current investigations, a two component material system made of fiber reinforced laminates bonded by a polycarbonate facesheet was studied. Laminates made of both unidirectional graphite/epoxy prepregs and S2-glass twill weave woven fabric/SC-15 resin systems were used in the study. Specimens of size 304.8 × 304.8 mm were made using different thickness ratios of facesheet and the backing laminate. Three different thicknesses of s2-glass laminates (3.17, 4.31 and 5.71 mm) were used to bond to two polycarbonate sheets of thickness 2.54 and 3.17 mm each. Similarly, three different thickness of graphite/epoxy laminates (2.05, 3.75 and 7.62 mm) were used to bond to polycarbonate facesheet of thickness 1.00, 3.175, and 4.30 mm. The ballistic tests are performed with a space test setup using fragment simulating projectiles(FSP). The ensuing damage was evaluated using ultrasonic C-scan technique using pule-echo immersion method.
Improvement of Vibration Damping Capacity and Fracture Toughness in Composite Laminates by the Use of Polymeric Interleaves
Authors: Gibson Ronald F. , Zhao Hui 
Published: December 2021

Abstract
It is shown that simultaneous improvement of vibration damping capacity and interlaminar fracture toughness in composite laminates can be achieved by using polymeric interleaves between the composite laminae. The specific case of Mode II interlaminar fracture toughness and flexural damping capacity of interleaved composite laminates is studied. Graphite/epoxy, E-glass/epoxy and E-glass/polyetherimide composite laminates with polymeric interleaves of several different thicknesses and materials were tested using both the end notch flexure (ENF) test for Mode II fracture toughness and the impulse-frequency response test for flexural damping capacity. The Mode II energy release rate GIIc for all three composites increased linearly with increasing interleaf thickness up to a critical thickness, then dropped off with further increases in thickness. The damping loss factor η for all three composites increased linearly with increasing interleaf thickness up to the maximum thickness. Analytical models for predicting the influence of interleaves on GIIc and η are developed, along with a hypothesis for the critical thickness effect with regard to fracture toughness.
Nondestructive Identification of Steel Bars by Modal Damping Measurements
Authors: Ayorinde Emmanuel O. , Morle Beverley , Zheng Zhiyang 
Published: December 2021

Abstract
This paper addresses the determination of modal vibration parameters for two batches of differently-treated steel reinforcement bars, as a means towards developing a method for easy identification of the state of mechanical goodness of such bars. The parameters measured for each bar are the resonance frequencies and corresponding modal damping loss factors for the first three vibration modes. This was done with the bar mounted in the cantilever mode, with varying free lengths. Inferences were made from the results to show which parameters would be suitable as state identifiers for bar specimens.
Finite Element Modeling and Advanced Imaging by Instrumented Tap Testing
Authors: Dayal V. , Choudhary Tanveer A. , Hsu D. K. , Peters J. J. , Barnard D. J. 
Published: December 2021

Abstract
Tap test is a very trusted and well used technique for the non-destructive evaluation of composite materials. Conventionally, a coin has been used for the tapping and the inspector listens to the resulting sound. The more advanced force response provides a number which can be correlated to the damage.
A finite element model of the test has been developed with full honeycomb features and a dynamic tap is applied. The goal is to measure the reduction in stiffness of the structure due to simulated defects. This could be useful to both the manufacturer, as well as the user, to know the change in the structural response of the structure for a possible pass/fail criteria.
We will also present results of an instrumented tap test with scanner. The main emphasis is on the testing of honeycomb core with composite face sheet panels. The results presented show the sensitivity of the tap test on simulated defects in honeycomb panels.
A Comparison of Matched-Field and Pseudo-Inverse Methods for Source Identification on a Frame Structure
Authors: Craun Matthew A. , Feit David 
Published: December 2021

Abstract
The combined use of pseudo-inverse and matched-field processing methods is investigated for localizing and characterizing a broad-band random vibration source on a lightly-damped finite frame structure. The low-frequency range where global modes of the frame are dominant in the response is considered. Experimental results for two different sensor array geometries are compared. Also, the use of numerically-derived transfer functions is demonstrated for each of the processing methods. The results indicate that a combined use of matched-field and pseudo-inverse methods allows for a more complete characterization of the frame excitation than either method used exclusively.
Visualization of Acoustic Pressure Radiation From Complex Vibrating Structures
Authors: Rayess Nassif , Wu Sean F. 
Published: December 2021

Abstract
This paper demonstrates visualization of the radiated acoustic pressures from a complex structure by using the Helmholtz Equation Least Squares (HELS) method (Wang and Wu, 1997; Wu and Wang, 1998; Wu and Yu, 1998). The structure under consideration has the same geometry and dimensions as those of a real, full-size passenger vehicle front end. Random noises generated by a high-fidelity loudspeaker installed inside the vehicle buck are measured at certain distances away from the vehicle surface. These measured signals are taken as the input to a computer model based on the HELS method. Experiments are conducted inside a 12’ by 12’ by 6.5’ walk-in size, fully anechoic chamber at the Acoustics, Vibration and Noise Control Laboratory of Wayne State University. The reconstructed acoustic pressures on the vehicle buck surface and in the field are compared with the measured data at the same locations. Also shown are comparisons of the reconstructed and measured acoustic pressure spectra at various locations on the vehicle buck surface. Results show that good agreements can be obtained with relatively few expansion functions in the low-to-mid frequency range. The accuracy of reconstruction, however, decreases with the increase of the excitation frequency and measurement distance as expected. Nevertheless, the HELS method is shown to be relatively insensitive to the complexities of a vibrating structure, which may make it potentially a viable noise diagnostic tool for engineers.
Radiation Efficiency of Convected Fluid Loaded Plates
Authors: Frampton Kenneth D. 
Published: December 2021

Abstract
The radiation of sound from geometrically simple vibrating structures into stationary fluids is well understood. However, to date, very few investigations have considered the effects that a convected fluid has on structural acoustic radiation. The purpose of this investigation is to quantify the effects of changes in flow velocity on the sound radiated from a vibrating elastic plate into a convected fluid medium. The discussion will include a description of modeling an elastic plate imbedded in an infinite baffle and radiating into a semi-infinite convected fluid field. Furthermore, the importance of a coupled model approach (where the fluid pressures generated by the plate motion in turn force the plate response) will be discussed. It will be demonstrated that the effects of convected fluid loading on sound radiation can be very significant.
Modeling and Analysis of a Tunable Bistable MEMS for Opto-Mechanical Computational Logic Elements
Authors: Saif M. Taher A. , Miller Norm R. 
Published: December 2021

Abstract
We present the design, analysis, and testing of a tunable bi-stable MEMS device that changes state when subjected to a threshold force in the range of pN to μN. It consumes power during change of state, but not while maintaining a state. Depending on the design and tuning, the state change can be initiated by even a moderate power laser beam that generates force by the impacts of its photons. The device presents itself as a potential bistable multivibrator (flip-flop), as well as the basic component of combinational logic elements, such as AND and OR gates, thus opening the door for low power digital opto-mechanical computing in normal to harsh environments. Several designs of the combinational logic elements are provided for optomechanical computing. In addition to bi-stability, the device shows a rich and complex set of dynamical behavior (e.g., chaotic response) when subjected to certain parametric excitations.
X-Ray Fabrication of Repetitive Structures
Authors: Liu Yadong , Sheng Paul 
Published: December 2021

Abstract
The fabrication of repetitive mechanical structures in millimeter range by deep x-ray micromachining is reported in this paper. With higher energy and wider x-ray beam lines available, macro-sized mechanical structures with micro-level features can be fabricated by the modified LIGA process to meet the need on high aspect ratio, high precision components in advanced applications. Through metrology study, better understanding of the process characteristics is achieved to provide important information on error modes in pattern transfer, which could be ultimately used in product design and process planning. Case studies of a rectangular HESSI grid structure and involute gear teeth are presented.
Viscous Damping of On-Substrate Torsional Micromirrors
Authors: Kim Eung-Sam , Han Ki-Ho , Cho Young-Ho 
Published: December 2021

Abstract
In this paper, we present theoretical and experimental study on the viscous damping of the on-substrate torsional micromirrors, oscillating near the silicon substrates. In the theoretical study, we develop theoretical models and test structures for the viscous damping of the on-substrate torsional micromirrors. From a finite element analysis, we obtain the fundamental modes of the torsional micromirrors, fabricated by the surface-micromachining process. From the electrostatic test of the fabricated devices, rotational velocity of the micromirrors has been measured at the atmospheric pressure using the Mach-Zehnder interferometer system. Experimental damping coefficients have been extracted from the least square fit of the measured rotational velocity within the filter bandwidth of 150kHz. We have compared the theoretical values and the experimental results on the dynamic performance of the micromirrors. The theoretical analysis overestimates the resonant frequency in the amount of 15%, while underestimating the viscous damping in the factors of 10%, respectively.
High Performance Electrostatic Air Valves Formed by Thin-Film Lamination
Authors: Biegelsen David K. , Cheung Patrick , Swartz Lars E. , Jackson Warren B. , Berlin Andrew A. , Lau Rachel 
Published: December 2021

Abstract
Electrostatic flap valves for rapidly modulating air flows through directed jets have been fabricated by simple lamination techniques as extensions to standard printed circuit board technology. The flaps have thicknesses of a few microns whereas the lateral dimensions are several millimeters. The laser cutting and lamination processes are described here and the characteristics of the valves are presented. Flow rise and fall times of order 1 ms are demonstrated, the variations of response times with drive voltage and pressure differential are shown, and lifetimes greater than 4 × 108 are reported.
A Silicon Micromachined Valve Driven by a Bi-Stable Electromagnetic Actuator
Authors: Böhm S. , Burger G. J. , Korthorst M. T. , Roseboom F. 
Published: December 2021

Abstract
In this contribution a micromachined open/closed valve is presented which is driven by a conventionally manufactured bistable electromagnetic actuator. Basically the micromachined valve part, 7 × 7 × 1 mm3 in dimension, is a sandwich construction of two KOH etched wafers with a specially formulated silicone rubber layer in between. This rubber sheet forms a flexible flow path, which can be open and closed to control a fluid flow. In order to provide a large stroke of about 200 μm, a precision-engineered bi-stable electromagnetic actuator was selected. This actuator consists of a spring-biased armature that can move up and down in a magnetically soft iron housing, incorporating a permanent magnet and a coil. It will be shown that this combination of micromachined and precision-engineered components provides the required low dead volume on the one hand and a large actuator stroke on the other. Another benefit of the application of a bi-stable actuator is the fact that only energy is needed in order to switch between the open and closed state. Moreover, the large stroke makes the valve particle tolerant thus allowing media like cell suspensions and whole blood.
A Stiction Study via C-V Plot Electrostatic Actuation/Latching
Authors: O’Brien Gary , Lin Liwei , Monk David J. 
Published: December 2021

Abstract
We have demonstrated a stiction study methodology on the microscale via an electrostatically actuated polysilicon parallel plate capacitor. The actuator was used to cause physical contact between two polysilicon microstructures. C-V (capacitance-voltage) plots were used to extract mechanical parameters, including surface energy (J/m2), force of adhesion (N), and spring constant (N/m). An average surface energy of 8.9 mJ/m2 with corresponding standard deviation (σ) of 0.8 mJ/m2 was observed regarding polysilicon adhesion. The average force of adhesion was calculated to be 13.3 μN (σ = 1.2 μN) for a contact surface area of 1.256 × 10−9 m2. The calculated Z-axis spring constant was 15.9 N/m (σ = 1.6 N/m) as compared to the theoretical value of 16.8 N/m.
Implementation and Analysis of Polymeric Replication by Micro-Injection Molding
Authors: Shah Jatan , Su Yu-Chuan , Lin Liwei 
Published: December 2021

Abstract
Injection molding technique for the replication of polymeric microstructures is demonstrated. By means of appropriate process control, traditional injection molding technique can be applied for the replication of polymeric microstructures. Using wet-etched silicon wafers as mold inserts, we have successfully predicted, improved, and optimized the replication results. The behavior of polymer melt in micro mold cavity is characterized by both experimental and simulation results. Temperature parameters are identified as the key factors that decisively determine the quality of molded microstructures. Optimization of the molding process is performed using simulation and experiment evaluation approach. This technique has potential applications for MEMS fabrication at relatively lower cost with a short cycle time. We believe this adoption of the injection molding process to micro-fabrication will lead to a promising technique for MEMS devices.
Low Voltage Dual-Mass Oscillator
Authors: Dyck Christopher W. , Allen James J. , Huber Robert J. 
Published: December 2021

Abstract
In this work we explored an alternative approach to mechanical oscillator design: the dual-mass oscillator. A two-degree-of-freedom system forced at antiresonance can attain larger vibration amplitudes at a given drive voltge with parallel-plate actuation than with comb drive actuation. Amplitudes of 0.85 μm in air at atmospheric pressure were observed with supply voltage under 5V. Amplitudes at resonance and antiresonance were measured. The parallel plate structure exhibited instability at low drive voltages because of the nonlinear drive. Structures with stiffer springs will solve this problem. An expression for the electrostatic force vs. displacement was developed using finite element methods. When this expression was used in simulations, the absorber mass steady-state amplitude closely matched measurements. Finite element analysis was done on the dual-mass oscillator. The natural frequencies of the out-of-plane modes were close to the in-plane modes and could potentially cause problems, depending on the magnitude of the out-of-plane force.
Experimental and Numerical Study on Micro-Stereolithography of Ceramics
Authors: Sun C. , Jiang X. N. , Zhang X. 
Published: December 2021

Abstract
Micro-stereolithography (μSL) uses laser light to solidify UV-curable resin mixed with concentrated ceramic powders. During the μSL process, the light scattering from the particle suspension is found to significantly influence the fabrication resolution and curing depth which are critical for the complex 3D microfabrication. In this work, we developed a novel doping technique to substantially reduce the light scattering; thus, enhance the fabrication precision and control. Both Monte-Carlo simulations and experimental studies are carried out to understand the detailed micro-scale optical scattering, chemical reaction (polymerization) and their influences to fabricated line-width.
Characterization of Silicon/Glass Anodic Bond Initiation Toughness
Authors: Labossiere Paul E. W. , Dunn Martin L. , Cunningham Shawn J. 
Published: December 2021

Abstract
We describe an approach to characterize the initiation toughness of silicon/glass anodic bonds based on the universal stress state that exists at the most common site of fracture initiation: the silicon/glass interface corner. The approach consists of a rigorous mechanics-based framework to assess the initiation toughness of anodic bonds; it can be used to rank bond toughness as a function of processing parameters and to facilitate the design of reliable bonds. By initiation toughness, we mean the resistance of anodic bonded interfaces to crack initiation under mechanical and/or thermal loading. The framework is universal in that it is independent of the bond size (area), and it is possible to discriminate between different failure modes via the initiation toughness. In order to validate the approach we designed and fabricated relatively simple anodic bond test specimens and carried out a mechanical test program to characterize bond toughness. We find that while failure stresses vary significantly with bond area, the inferred toughness is invariant with respect to bond area.
Multiple Through-Wafer Interconnects for Stacking of Microsystems
Authors: Heschel Matthias , Rasmussen Kurt , Kuhmann Jochen F. , Bouwstra Siebe 
Published: December 2021

Abstract
This paper describes a novel technology for multiple wafer frontside to backside interconnects, which has been applied to a multifunctional interconnect layer for an integrated microphone for hearing aid applications. Besides the interconnect layer with relatively large through-holes the stack consists of the microphone itself and an integrated circuit chip for signal conditioning. The patterning of the metallization on the interconnect wafer has been done using electrodepositable photoresist as mold for electroplating of a variety of metals. For the interconnect metallization we use copper. The bonding pads on the microphone side of the interconnect layer have been provided with under bump metallizations (UBM) and solder bumps. The IC side features a top surface metallization (TSM) suitable for conductive adhesive bonding. The realized feedthrough wires show good electrical performance in terms of low series resistance (100 mΩ) and small parasitic capacitance (&lt; 1 pF).
Design and Development of a Unit-Use Cartridge for Coagulation Testing in Whole Blood
Authors: Cheadle Rhonda , Maczuszenko Andy , Opalsky Cindra Widrig 
Published: December 2021

Abstract
The following describes the development of a disposable cartridge for use at the patient bedside to perform traditional coagulation assays on fresh whole blood samples. The cartridge provides a means by which a blood sample can be metered and quantitatively mixed with reagents that activate the coagulation cascade. Clot formation is subsequently detected using a microfabricated sensor housed within the cartridge. The functional features of the cartridge and sensor are described.
Analysis of Absorbed Power Distribution in Ride Dynamics — Evaluation of Driver’s Comfort
Authors: Tong Rick T. , Amirouche Farid , Nishiyama Shuji 
Published: December 2021

Abstract
This paper presents an analytical model for the evaluation of the distribution of the absorbed power and how the body reacts to the road excitation. “Absorbed power” is a popular method used to evaluate ride comfort. Since Pradko and Lee introduced it in 1960’s [1,2], researchers focused on the “absorbed power” transmitted to the body as a single indicator of body tolerance and fatigue. How the body absorbs energy and how it distributes it remains a mystery. This paper attempts to shed some light on how this energy is transmitted to different parts of the body and what is at stake when the input conditions change. A six degree of freedom (dof) lumped mass model was developed to investigate the energy absorption and the work performed by the muscles (springs and dampers) during a rough ride. A better understanding of the energy flow between the body segments may give us an idea on how the seat and its suspension should be designed.
The Biplanar Bicycle
Authors: Reinholtz C. F. , Bay J. , Soper R. Randall , Abbott M. , Grove D. 
Published: December 2021

Abstract
Two wheeled vehicles, or bicycles, are widely accepted devices. Almost invariably, however, the term bicycle brings to mind a planar, statically unstable, two-wheel vehicle that must be kept upright by the dynamic control of the rider. This mindset may be logical in the limited context of some human-controlled devices, but it may limit our creative potential when considering the design of autonomous vehicles and novel means of transport. Here we attempt to challenge mindset and myth, asking the reader to consider a concept that may be counterintuitive, but that is rooted in the sound application of engineering principles. We propose the biplanar bicycle.