bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of SHM With the Electromechanical Impedance Method Using a High Voltage Excitation Signal in High Frequencies
Authors: Nolan Eric C. , Safaei Mohsen , Anton Steven R. 
Published: December 2019

Abstract
Structural health monitoring (SHM) has originally been used for static structures. With the development of high-speed data acquisition technology, SHM systems can monitor structures in seconds. Advanced SHM systems for use in dynamic environments require operation in the microsecond timescale. One promising approach is the electromechanical impedance (EMI) technique. The EMI method monitors the impedance of a structure, and damage is indicated by changes in the impedance. Standard impedance measuring hardware are not practical for microsecond detection due to their slow sampling speeds. Faster impedance measuring techniques have been developed and allow for customizable excitation signals. Researchers have also considered taking measurements at higher frequencies to decrease the measurement time. Past works indicate sensitivity to damage is limited above 600 kHz. The goal of this study is to evaluate the sensitivity of the EMI method to damage with a high voltage excitation signal. It was hypothesized that increasing the voltage would increase damage sensitivity at higher frequencies. In this study, the amplitude of the excitation signal was increased using a high frequency voltage amplifier. A PZT disk bonded to a cantilevered aluminum beam was used as the test structure. Damage was created by decreasing the length of the beam. Finite element (FE) simulation was also employed to achieve a better understanding of the experiment. From the results of the experiment and FE model, using a higher excitation voltage has proven not to increase the sensitivity level of the EMI method. Higher voltages do improve the precision of the measurement by increasing the signal to noise ratio.
A Piezocomposite Solid-State Rotor: Theoretical Analysis of Thrust and Efficiency Metrics
Authors: Carneiro Ferreira de Castro Taís , Bilgen Onur 
Published: December 2019

Abstract
This paper presents a summary on the ongoing research and development of a solid-state piezoelectric composite rotor design for use in rotary systems. The paper focuses on the theoretical analysis of a two-bladed rotor with varying parameters such as flight speed, blade pitch angle, and rotational speed. XROTOR, a blade element method based software, is used for analysis. The two-dimensional aerodynamic characteristics are acquired from the previous research on a Macro-Fiber Composite actuated simply supported thin airfoil. A set of simulations are conducted to determine the best geometric configuration, so the piezoelectric increase in thrust is maximized. The proposed hub-rotor system has the potential to be implemented in unmanned-aerial-vehicles such as single-rotor, tandem-rotor, multi-copter, and ducted-fan rotorcraft, or other rotating systems such as wind turbines, turbine engines, and marine propellers. This paper presents a summary of previous findings on a solid-state rotor prototype, and a new investigation on the theoretical aerodynamic behavior.
Initial Analysis of a Novel Biomimetic Span-Wise Morphing Wing Concept
Authors: Stacey Benjamin J. , Thomas Peter 
Published: December 2019

Abstract
Morphing wings and the adaptive systems they form have been developed significantly over recent decades. Increased efficiency and control performance can be achieved with their implementation, while advances in material technology, system integration and control, have allowed concepts to present a realistic alternative to fixed-wing and aft-tail aircraft. Set out in this paper is the preliminary design and development for a novel span-wise morphing concept which employs and heavily implements biomimetic design. Specifically, the skeletal structure of the bird wing by mimicking the humerus, ulna/radius, and carpometacarpus of birds of prey as they exhibit the most versatile wing shape enabling multiple manoeuvre and flight types. The concept comprises three sections corresponding to the skeletal structure, each consisting of a leading edge D-spar and an internal structural member onto which trailing edge plates are mounted. Pneumatic artificial muscle (PAM) actuators are presented as a drive for a biologically derived ‘drawing-parallels’ mechanism, through which a 75% semi-span length change and variable sweep angle, can be obtained. Analysis of initial CFD results is discussed in comparison with similar concepts in the field and a proposal for small scale wind tunnel verification put forward. While a rapid prototype is printed to confirm the viability of the concept.
Modeling and Design of an Experimental Demonstrator of Blade Twist Through the SMA Technology
Authors: Ameduri Salvatore , Concilio Antonio , Galasso Bernardino 
Published: December 2019

Abstract
The paper at hand focuses on the modeling and design of an experimental demonstrator of a blade segment, twisted through Shape Memory Alloy technology. The demonstrator will be used for the wind tunnel tests planned within the Project of SABRE (H2020 Eu Program), aimed at investigating the effects produced by blade oriented morphing technologies, both in fixed and rotary wing configurations. The design approach adopted for a SMA twist concept is herein described in its different phases, moving from the definition of the preliminary layout, its fitting to the reference blade mechanical features, the preliminary structural analysis to confine its operational envelope, up to the simulation of the SMA actuation through a SMA torque element. The results are presented in terms of operational envelope limits and transmitted twist.
Integrated Rotor Performance Improvement and Vibration Reduction Using Active Camber Morphing
Authors: Kumar Sumeet , Komp Dominik , Hajek Manfred , Rauleder Jürgen 
Published: December 2019

Abstract
This paper discusses open-loop and closed-loop active control investigations of a full-scale Bo 105 helicopter rotor with active camber morphing. The potential of an active camber morphing concept to reduce non-rotating vibratory hub loads and rotor power using active control was investigated. The mechanism employed was a dynamically actuated airfoil camber morphing concept known as Fish Bone Active Camber (FishBAC) that smoothly deforms the camber over the aft section of the airfoil. A comprehensive rotorcraft aeromechanics analysis was used that modeled the blade elastic motion using one-dimensional finite beam elements combined with multibody dynamics. Aerodynamic forces were calculated with a free-vortex wake model together with lifting line theory for the blade aerodynamics. The open-loop investigation comprised of a parametric study of relevant control parameters that govern the active camber deflection cyclic actuation profile and their effects on rotor performance and hub vibration. It was found that active camber morphing using superimposed once-per-revolution (1P) and 2P control inputs was able to simultaneously reduce rotor power by 4.3% and overall vibratory hub loads by 27%. Additionally, a closed-loop adaptive multicyclic controller was used to identify the potential of this morphing concept for hub vibration reduction using multicyclic active control inputs. Active camber actuation using a sum of four control harmonic inputs, i.e. 1-4P, resulted in a maximum hub vibration reduction of 50%.
Graph-Based Interpretation of L-System Encodings Toward Aeroelastic Topology Optimization of a Morphing Airfoil in Supersonic Flow
Authors: Bielefeldt Brent R. , Hartl Darren J. , Hodson Joshua D. , Reich Gregory W. , Beran Philip S. , Pankonien Alexander M. , Deaton Joshua D. 
Published: December 2019

Abstract
This work details the preliminary design of a morphing airfoil in supersonic flow using evolutionary design principles. The structural topology of the airfoil includes a fixed outer mold line, fixed spars, and designable internal stiffeners and actuators. The designable components are generated using a bio-inspired model known as a Lindenmayer System (L-System), which encodes design variables and governs the development of a structural topology when coupled with an interpretation algorithm. Here, we utilize a graph-based interpretation scheme known as Spatial Interpretation for the Development of Reconfigurable Structures (SPIDRS), which has been shown to effectively explore the mechanism design space using a limited number of design variables. The optimization process behind this preliminary design problem is discussed, and optimal airfoil topologies capable of meeting specified aerodynamic performance criteria are presented in hopes of gaining a better understanding of how actuation systems could be integrated into the next generation of aircraft.
Quantitative Measurement of Thin Film Adhesion Force
Authors: Tsai Li-Chih , Rezaee Maysam , Haider Muhammad Istiaque , Yazdi Armin , Salowitz Nathan P. 
Published: December 2019

Abstract
Thin film and micro-fabricated devices are increasingly being used in actuators, sensors, and processors deployed in smart materials. The physical survival of these devices is paramount to their usefulness but existing methods for testing and analysis are limited and challenging due to their properties. The most common test involve the manual application and removal of (unspecified) tape but does not provide a result in scientific units and has large variation (&gt; 35%). This paper presents a study into the effects of parameters of tape application and peeling on the adhesion strength of the tape. This information was then used to create a test methodology using commonly available laboratory equipment, which would control these parameters to minimize variation and produce repeatable quantitative results. Experiments using this test methodology were performed with tape directly adhered to several different substrates as well as tape adhered to a thin film which was then peeled off of a backing. Ongoing work is seeking to identify and address different forms of failure including adhesive failure, cohesive failure, or survival.
Mechanics of Post Constrained Recovery Residual Stress Produced by NiTi
Authors: Haider Muhammad Istiaque , Yazdi Armin , Rezaee Maysam , Tsai Li Chih , Salowitz Nathan 
Published: December 2019

Abstract
Recent research has revealed that Nickel Titanium (NiTi) shape memory alloys can produce residual stresses after undergoing constrained recovery and returning to their low temperature, martensitic state while still constrained. The nature and underlying mechanisms that cause this post constrained recovery residual stress (PCRRS) are not well understood. This paper presents experimental research and results seeking to further understand the PCRRS. Experiments were performed on multiple formulations of NiTi subjected to: 1) Cyclic loading and training before producing PCRRS, 2) Repeated thermomechanical loading with large strains followed by a thermal cycle to create and re-generated the PCRRS, and 3) Creation of the PCRRS followed by repeated cycles of small, 0.5% strains.
Experiments found that the training in 1) did not significantly alter the ability to produce PCRRS or its magnitude. Straining samples from the PCRRS state could reduce the residual stress state to zero stress, but the PCRRS could be recreated by repeating thermal actuation with the only significant variation being a reduction in magnitude for the first to second cycle. Multiple small strain cycles applied from the PCRRS state caused an incremental reduction in residual stress. The full PCRRS could be re-created by repeating the initial thermomechanical cycle. The values of the residual stress varied across the first 3 sets of cycles, but from the third set onward the response stabilized.
These results indicate that the primary mechanisms for generating a PCRRS are stable and recoverable with only minor and diminishing variations due to training or repeated regeneration of the PCRRS. Grain boundary stabilization and similar mechanisms may be responsible for the minor variation between the first few regenerations of the PCRRS. The incremental reduction in the residual stress after exposure to small 0.5% strains must be due to a recoverable process like partial and accumulating detwinning of the NiTi with each load cycle.
Further work is underway to perform microstructural analysis of samples in the various states to further the theorized material states.
The ability to generate and control PCRRS has the potential to find new application and advance capabilities in fields like self-healing and fatigue resistant materials by generating stresses without the continuous application of heat energy. New forms of actuation could also be developed based on the potential energy stored in a structure through PCRRS.
Chord Morphing for Helicopter Rotor Blades
Authors: Riemenschneider Johannes , Balzarek Christoph , van der Wall Berend G. , Majeti Rohin Kumar 
Published: December 2019

Abstract
Since helicopter rotors have different demands from different flight stats, the final design is always a compromise between flight stats such as hover and fast forward flight. Two of the design parameters are twist and chord length. This paper is giving some reasoning from rotor simulations on what twist and chord length should look like in order to increase performance in hover or forward flight. The result is, that the inboard chord length should be much larger for hover than for forward flight. This paper is presenting a structural concept, that can enable a helicopter rotor blade to change its chord length.
Ultrasonic De-Icing System for Leading Edge in Composite Material
Authors: Maio Leandro , Ameduri Salvatore , Memmolo Vittorio , Ricci Fabrizio , Concilio Antonio 
Published: December 2019

Abstract
The paper presents a numerical study about a de-icing system using ultrasonic waves. The activity is developed within the project “SMart On-Board Systems” (SMOS), which is part of Italian Aerospace National Research Program, funded by the Italian Ministry of Education (MIUR) and Research and coordinated by Italian Aerospace Research Centre (CIRA). The system is conceived for an aircraft wing leading edge and it shall be extended to other aircraft components, once its efficiency and reliability will be demonstrated. In this work, a numerical study about a 0012 NACA profile in composite material is discussed and the simulations results coming from finite element analyses in frequency and time domains are presented.
Pneumatic Artificial Muscle Actuators With Integrated Controls for Space Flight Applications
Authors: Netwall Christopher J. , Thomas James P. , Kubista Michael S. , Griffith Kerry A. , Kindle Christopher , Schlater Jordan , Hays Joseph T. , Feerst Phillip A. , Wereley Norman 
Published: December 2019

Abstract
The U.S. Naval Research Laboratory (NRL) has been developing a space-rated 7 degree of freedom (DOF) robot arm with a high payload-to-mass ratio as an alternative design to motor-gear driven robotic manipulators. The robot arm employs antagonistic pairs of pneumatic artificial muscle (PAM) actuators to control each degree-of-freedom (DOF) to achieve large force outputs relative to the PAM component masses. A novel feature of the NRL PAM actuator was the integration of the pneumatic control components inside the pressure-bladder, which not only reduces the volume of the robotic arm hardware but also reduces the pressurized-gas actuation volume in the PAM enabling significant reductions in gas consumption during actuation. This multifunctional design enables reductions in launch-weight costs and increases in operational endurance for space applications. The integration of these PAMs into a well-designed robotic-arm structure, in tandem with a newly developed control algorithm, has the potential to exceed the performance metrics of traditional motor-driven robot arms. This paper describes the development of the improved efficiency PAM design that is advancing this technology towards space flight readiness.
A Wearable Biomedical Motion Sensor Employing a Vibration Energy Harvester
Authors: Sharghi Hesam , Daneault Jean-François , Bilgen Onur 
Published: December 2019

Abstract
Wearable motion sensors find a great number of applications in the biomedical field by recording real-time movements and transferring data to mobile electronics. Patients with hyperkinetic movements is a group of interest for such sensors to survey their conditions for long periods. Longer and more frequent recording intervals are necessary to diagnose and treat patients’ disease. Mobile battery-operated motion sensors have a limited recording span, and they need to be charged frequently, which is inconvenient for most of the patients. In this study, vibration energy harvesters are employed to extend the battery life of motion sensors: one step closer to make autonomous sensors without chargers. A vibration energy harvester is designed for a motion sensor to harvest energy from involuntary movements of patients with hyperkinetic movements. An analytical model for charging and discharging cycles is developed to predict the battery life based on the amount of harvested power. Preliminary data from commercial devices are used as a foundation for the design and the current feasibility study.
Continuous Operating Elastocaloric Heating and Cooling Device: Model-Based Parameter Study With Airflow Losses
Authors: Welsch Felix , Kirsch Susanne-Marie , Michaelis Nicolas , Motzki Paul , Schütze Andreas , Seelecke Stefan 
Published: December 2019

Abstract
Elastocaloric cooling uses solid-state NiTi-based shape memory alloy (SMA) as a non-volatile cooling medium and enables a novel environment-friendly cooling technology. Due to the high specific latent heats activated by mechanical loading/unloading, substantial temperature changes are generated in the material. Accompanied by a small required work input, a high coefficient of performance is achievable.
Recently, a fully-functional and illustrative continuous operating elastocaloric air cooling system based on SMA was developed and realized. To assist the design process of an optimized device with given performance and efficiency requirements, a fully coupled thermo-mechanical system-level model of the multi-wire cooling unit was developed and implemented in MATLAB. The resulting compact simulation tool is qualified for massively parallel computation on modern multi-core computers, which allows fast and comprehensive parameter scans.
The comparison of first measurements and simulation results showed differences in the system performance. As the airflow rate influences the thermal power and the outlet temperature significantly, the demonstrator is extended with a spatial airflow measurement system to analyze the crossflow between the hot and cold side. Following, the fluid transport model is advanced by the effect of cross-flow losses, and first modeling results with the variation of airflow rate and rotation frequency are presented.
Controlled Operation of Lithium Ion Batteries Using Reversible Shutdown Membrane Separators
Authors: Hery Travis , Sundaresan Vishnu Baba 
Published: December 2019

Abstract
In this paper, we demonstrate the application of the ionic redox transistor as a reversible shutdown membrane separator (RSMS) in a custom designed Li-ion battery (LIB). The oxidized state corresponds to the OFF state and reduced state corresponds to the ON state of the RSMS in the LIB. It is demonstrated that RSMS reversibly enables and disables the LIB from charging/discharging as it is switched between its reduced (ON) and oxidized (OFF) state, respectively. The operation of the LIB with RSMS is compared with a standard LIB fabricated from identical cathodes and anodes at various C-rates.
The specific capacity of the standard LIB is 144, 132, and 50 mAh/g at C/12, C/4, and C/2 rates, respectively. The specific capacity of the LIB with RSMS in the reduced state is 134, 108, and 48 mAh/g at C/12, C/4, and C/2 rates, respectively, showing similar capacity to the standard LIB at all C-rates. The specific capacity of the LIB with RSMS in the oxidized state is 125, 11, and 5 mAh/g at C/12, C/4, and C/2 rates, respectively, demonstrating a capacity decrease compared to the reduced state at all C-rates.
Self-Sensing Characterization of GNP and Carbon Black Filled Cementitious Composites
Authors: Jiang Zhangfan , Ozbulut Osman E. , Xing Guohua 
Published: December 2019

Abstract
Over the past decades, a number of structural health monitoring methods have been developed for condition assessment of concrete structures. Most of these methods require the installation of external sensors. Accelerometers are commonly used for vibration-based damage detection for the entire structure, while strain gauges are installed in order to detect cracking and damage at the component level. Conventional strain sensors, such as metal foil strain gauges, have been widely used to monitor local conditions in concrete structures. However, all of these sensors have certain shortcomings such as exhibiting limited durability and low gauge factor, and providing only pointwise strain measurements. Multifunctional cement-based composites that can determine their own strain and damage can overcome the limitations of these traditional sensors.
This study explores the use of two different nanomaterials, namely graphene nanoplatelets (GNP) and carbon black (CB) for the development of self-sensing cementitious composites and the synergetic effects in their hybrid utilization. A simple fabrication method that does not require special treating procedures such as ultrasonication for dispersing nanomaterials is pursued. Twelve batches of mortar specimens reinforced with only GNP or CB at different concentrations, or with both GNP and CB fillers are prepared. A polycarboxylate-based superplasticizer is used to disperse nanomaterials and to increase the workability of the nano-reinforced mortar. Scanning electron microscope (SEM) is utilized to assess the distribution quality of nanomaterials. Standard cubic specimens are tested for compressive strength at 28 days. The bulk resistivity of the standard prismatic specimens is measured using the four-point probe method. The piezoresistive response of nano-reinforced cement composites is evaluated under the cyclic compressive loads.