Marc P. Mignolet

Bio: Marc P. Mignolet is an academic researcher from Arizona State University. The author has contributed to research in topics: Finite element method & Nonlinear system. The author has an hindex of 10, co-authored 15 publications receiving 575 citations.

Reduced Order Model for the Geometric Nonlinear Response of Complex Structures

Abstract: This paper focuses on the development of nonlinear reduced order modeling techniques for the prediction of the response of complex structures exhibiting “large” deformations, i.e. a geometrically nonlinear behavior, and modeled within a commercial finite element code. The present investigation builds on a general methodology successfully validated in recent years on simpler beam and plate structures by:(i) developing a novel identification strategy of the reduced order model parameters that enables the consideration of the large number of modes (> 50 say) that would be needed for complex structures, and(ii) extending an automatic strategy for the selection of the basis functions used to represent accurately the displacement field.The above novel developments are successfully validated on the nonlinear static response of a 9-bay panel structure modeled with 96,000 degrees of freedom within Nastran.Copyright © 2012 by ASME

Reduced order modeling for the nonlinear geometric response of cracked panels

Abstract: The focus of this investigation is on a first assessment of the predictive capabilities of nonlinear geometric reduced order models for the prediction of the large displacement and stress fields of cracked panels. First, a comparison of the basis functions employed for virgin and cracked panels revealed clearly visible crack effects but only on the transverse components of the “dual” modes, i.e. the part of the basis modeling primarily the in-plane displacements. Next, it was demonstrated that the reduced order models of both virgin and cracked panels provided a close match of the displacement field obtained from full finite element analyses of the cracked panel for moderately large static responses (peak displacement of 2 and 4 thicknesses). In regards to stresses, it was found that the cracked panel reduced order model led to a close prediction of the stress distribution obtained on the cracked panel as computed by the finite element model. Finally, two “enrichment” techniques, based on superposition of the crack effects on the virgin panel stress field, were proposed to permit a close prediction of the stress distribution of the cracked panel from the reduced order model of the virgin one. A very good prediction of the full finite element results was achieved with both enrichments.

Reduced order modeling for the static and dynamic geometric nonlinear responses of a complex multi-bay structure

Abstract: This paper focuses on the continued development and deepened validation of nonlinear reduced order models of structures experiencing large deformations. Of particular interest here is a complex structure with rich dynamics: a previously introduced 9-bay panel with stiffeners and longerons modeled by finite elements using approximately 96,000 degrees-of-freedom. Building on a general methodology successfully validated in recent years on simpler beam and plate structures, a reduced order model of the panel motions is developed step-by-step. This 85-mode model is shown by comparison with full finite element (Nastran) results to lead to accurate predictions of both static and dynamic responses of the panel. Coupling of this reduced order model with piston-theory aerodynamics is also achieved to demonstrate the capability of these reduced order models to support multidisciplinary analyses.

Coupled reduced order model-based structural-thermal prediction of hypersonic panel response

Abstract: This paper addresses some aspects of the development of a fully coupled thermal-structural reduced order modeling of planned hypersonic vehicles, most notably the construction of the thermal and structural bases. A general framework for this construction is presented and demonstrated on a representative panel considered in prior investigations. The thermal reduced order model is first developed using basis functions derived from appropriate conduction eigenvalue problems. This basis is validated using published data of which it is found to provide an accurate representation. The coupling of this thermal model with a recently developed nonlinear structural reduced order model of the same panel is next considered. This coupling requires first the enrichment of the structural basis to model the elastic deformations that may be produced consistently with the thermal reduced order model. This step is detailed for the present panel and then the temperature dependent coefficients of the structural model are determined. The validation of the combined structural-thermal reduced order model is carried out by comparison with full finite element results (Nastran here) corresponding to pure mechanical loads, pure thermal loads, and combined mechanical-thermal excitations. Such comparisons are performed here on static solutions with temperature increases up to 2700R and pressures up to 3 psi for which the maximum displacements are of the order of 3 thicknesses. The reduced order model predicted results agree well with the full order finite element predictions in all of these various cases.

LQR-Based Least-Squares Output Feedback Control of Rotor Vibrations Using the Complex Mode and Balanced Realization Methods

Abstract: The complex mode and balanced realization methods are used separately to obtain reduced-order models for general linear asymmetric rotor systems. The methods are outlined and then applied to a typical rotor system which is represented by a 52 degree-of-freedom finite element model. The accuracy of the two methods is compared for this model and the complex mode method is found to be more accurate than the balanced realization method for the desired frequency bandwidth and for models of the same reduced order. However, with some limitations, it is also shown that the balanced realization method can be applied to the reduced-order complex mode model to obtain further order reduction without loss of model accuracy. An “Linear-Quadratic-Regulator-based least-squares output feedback control” procedure is developed for the vibration control of rotor systems. This output feedback procedure eliminates the requirement of an observer for the use of an LQ regulator, and provides the advantage that the rotor vibration can be effectively controlled by monitoring only one single location along the rotor shaft while maintaining an acceptable performance. The procedures presented are quite general and may be applied to a large class of vibration problems including rotor-dynamics.Copyright © 1992 by ASME

Digital Twin: Values, Challenges and Enablers From a Modeling Perspective

Abstract: Digital twin can be defined as a virtual representation of a physical asset enabled through data and simulators for real-time prediction, optimization, monitoring, controlling, and improved decision making. Recent advances in computational pipelines, multiphysics solvers, artificial intelligence, big data cybernetics, data processing and management tools bring the promise of digital twins and their impact on society closer to reality. Digital twinning is now an important and emerging trend in many applications. Also referred to as a computational megamodel, device shadow, mirrored system, avatar or a synchronized virtual prototype, there can be no doubt that a digital twin plays a transformative role not only in how we design and operate cyber-physical intelligent systems, but also in how we advance the modularity of multi-disciplinary systems to tackle fundamental barriers not addressed by the current, evolutionary modeling practices. In this work, we review the recent status of methodologies and techniques related to the construction of digital twins mostly from a modeling perspective. Our aim is to provide a detailed coverage of the current challenges and enabling technologies along with recommendations and reflections for various stakeholders.

Modeling and Analysis of Mistuned Bladed Disk Vibration: Status and Emerging Directions

Abstract: The literature on reduced-order modeling, simulation, and analysis of the vibration of bladed disks found in gas-turbine engines is reviewed. Applications to system identification and design are also considered. In selectively surveying the literature, an emphasis is placed on key developments in the last decade that have enabled better prediction and understanding of the forced response of mistuned bladed disks, especially with respect to assessing and mitigating the harmful impact of mistuning on blade vibration, stress increases, and attendant high cycle fatigue. Important developments and emerging directions in this research area are highlighted.

Mistuning-Based Control Design to Improve Closed-Loop Stability Margin of Vehicular Platoons

Abstract: We consider a decentralized bidirectional control of a platoon of N identical vehicles moving in a straight line. The control objective is for each vehicle to maintain a constant velocity and inter-vehicular separation using only the local information from itself and its two nearest neighbors. Each vehicle is modeled as a double integrator. To aid the analysis, we use continuous approximation to derive a partial differential equation (PDE) approximation of the discrete platoon dynamics. The PDE model is used to explain the progressive loss of closed-loop stability with increasing number of vehicles, and to devise ways to combat this loss of stability. If every vehicle uses the same controller, we show that the least stable closed-loop eigenvalue approaches zero as O(1/N2) in the limit of a large number (N) of vehicles. We then show how to ameliorate this loss of stability by small amounts of "mistuning", i.e., changing the controller gains from their nominal values. We prove that with arbitrary small amounts of mistuning, the asymptotic behavior of the least stable closed loop eigenvalue can be improved to O(1/N). All the conclusions drawn from analysis of the PDE model are corroborated via numerical calculations of the state-space platoon model.

Aeroelastic and Aerothermoelastic Analysis in Hypersonic Flow: Past, Present, and Future

Abstract: H YPERSONIC flight began in February 1949 when a WAC Corporal rocket was ignited from a U.S.-captured V-2 rocket [1]. In the six decades since this milestone, there have been significant investments in the development of hypersonic vehicle technologies. The NASA X-15 rocket plane in the early 1960s represents early research toward this goal [2,3]. After a lull in activity, the modern era of hypersonic research started in the mid-1980s with the National Aerospace Plane (NASP) program [4], aimed at developing a single-stage-to-orbit reusable launch vehicle (RLV) that used conventional runways. However, it was canceled due mainly to design requirements that exceeded the state of the art [1,5]. A more recent RLV project, the VentureStar program, failed during structural tests, again for lack of the required technology [5]. Despite these unsuccessful programs, the continued need for a low-cost RLV, as well as the desire of the U.S. Air Force (USAF) for unmanned hypersonic vehicles, has reinvigorated hypersonic flight research. An emergence of recent and current research programs [6] demonstrate this renewed interest. Consider, for example, the NASA Hyper-X experimental vehicle program [7], the University of Queensland HyShot program [8], the NASA Fundamental Aeronautics Hypersonics Project [9], the joint U.S. Defense Advanced Research Projects Administration (DARPA)/USAF Force Application andLaunch fromContinentalUnited States (FALCON) program [10], the X-51 Single Engine Demonstrator [11,12], the joint USAF Research Laboratory (AFRL)/Australian Defence Science and Technology Organisation Hypersonic International Flight Research Experimentation project [13], and ongoing basic hypersonic research at the AFRL (e.g., [14–20]). The conditions encountered in hypersonic flows, combined with the need to design hypersonic vehicles, have motivated research in the areas of hypersonic aeroelasticity and aerothermoelasticity. It is evident from Fig. 1 that hypersonic vehicle configurations will consist of long, slender lifting body designs. In general, the body, surface panels, and aerodynamic control surfaces are flexible due to minimum-weight restrictions. Furthermore, as shown in Fig. 2, these