Nick Cramer

Development of Mission Adaptive Digital Composite Aerostructure Technologies (MADCAT)

This paper reviews the development of the Mission Adaptive Digital Composite Aerostructures Technologies (MADCAT) v0 demonstrator aircraft, utilizing a novel aerostructure concept that combines advanced composite materials manufacturing and fabrication technologies with a discrete construction approach to achieve high stiffness-todensity ratio ultra-light aerostructures that provide versatility and adaptability. This revolutionary aerostructure concept has the potential to change how future air vehicles are designed, built, and flown, with dramatic reductions in weight and manufacturing complexity – the number of types of structural components needed to build air vehicles – while enabling new mission objectives. We utilize the innovative digital composite materials and discrete construction technologies to demonstrate the feasibility of the proposed aerostructure concept, by building and testing a scaled prototype UAV, MADCAT v0. This paper presents an overview of the design and development of the MADCAT v0 flight demonstrator.

Application of Transfer Matrix Approach to Modeling and Decentralized Control of Lattice-Based Structures

This paper presents a modeling and control of aerostructure developed by lattice-based cellular materials/components. The proposed aerostructure concept leverages a building block strategy for lattice-based components which provide great adaptability to varying ight scenarios, the needs of which are essential for in- ight wing shaping control. A decentralized structural control design is proposed that utilizes discrete-time lumped mass transfer matrix method (DT-LM-TMM). The objective is to develop an e ective reduced order model through DT-LM-TMM that can be used to design a decentralized controller for the structural control of a wing. The proposed approach developed in this paper shows that, as far as the performance of overall structural system is concerned, the reduced order model can be as e ective as the full order model in designing an optimal stabilizing controller.

RF Network Localization Method for Unmanned Robotics Systems

The paper presents a preliminary study towards developing a Global Positioning System (GPS) free localization method, which monitors the Received Signal Strength Indication (RSSI) between several stationary nodes (anchor nodes) and a mobile node to predict the position of the mobile node. The main goals of the paper are to find the optimal localization algorithm and identify the optimal number of anchor nodes that would provide the desired localization precision. It will be shown that the proposed technique is affordable and can be successfully used in electronically noisy environments (e.g., indoor). The study is performed with a 434 MHz RF localization system that should provide less interference than the typical 2.4 GHz systems that commonly experience interference from other domestic technologies. The results reveal the feasibility and shortcomings of these systems for designing a more accurate real-time positioning system.

Analysis of Contact Mechanics and Smoothed Particle Hydrodynamic Simulations of Viscoelastic Polymer Sine Waves

According the American Cancer Society’s data, in 2013, an estimated 53,640 people developed head and neck cancers [1], which accounts for about 3% to 5% of all cancers in the United States. Removing head and neck malignant neoplasms is one of the first stages towards patient recovery. However, these types of invasive procedures often lead to disfiguring scars and resections with functional and aesthetical drawbacks (see Figure 1).Copyright

Discrete Time Finite Element Transfer Matrix Method Development for Modeling and Decentralized Control

The current emphasis on increasing aeronautical efficiency is leading the way to a new class of lighter more flexible airplane materials and structures, which unfortunately can result in aeroelastic instabilities.To effectively control the wings deformation and shape, appropriate modeling is necessary. Wings are often modeled as cantilever beams using finite element analysis. The drawback of this approach is that large aeroelastic models cannot be used for embedded controllers. Therefore, to effectively control wings shape, a simple, stable and fast equivalent predictive model that can capture the physical problem and could be used for in-flight control is required.The current paper proposes a Discrete Time Finite Element Transfer Matrix (DT-FETMM) model beam deformation and use it to design a regulator. The advantage of the proposed approach over existing methods is that the proposed controller could be designed to suppress a larger number of vibration modes within the fidelity of the selected time step. We will extend the discrete time transfer matrix method to finite element models and present the decentralized models and controllers for structural control.© 2015 ASME

Vibration of Micro-Scale Structures: Accurate SPH Approach and Simplified Generalized Kelvin Model

Recent advances in polymer technology together with the growing need of smaller and lighter electronic components and biomedical equipment led to the development of new applications of polymers at micro scale. However, unlike traditional materials (e.g., metal silicon), polymers exhibit a significant time dependency in their response to load (e.g., viscoelastic, hyperelastic). Therefore, predicting the behavior of such polymer components at small scale requires accurate simulations of the effects of creep and relaxation within the systems. The current study uses a mesh-free particle method (smoothed particle hydrodynamics) to predict time-dependent mechanical response of polymers. As a first step towards investigating the response of a polymer microstructure under load, we simulate the behavior of a slender polymer rod compressed and tangentially dragged against a smooth glass surface.It is shown that although accurate prediction of polymer deformation cannot be achieved with a fully analytic model, a simplified generalized Kelvin model could calibrated to capture most of the characteristics of the fully numerical model. This cold be used for predicting the behavior under load of a passive subsystem of imbedded in a control algorithm to extend the measuring domain of a possible sensor or prevent potentially dangerous operating conditions.Copyright