Dynamics of Composite StructuresVibration behavior of composite structures is critical for a broad range of applications in diverse industries such as aerospace, automotive, and ship-building. This concept has attracted increasing attention due to its flexibility to achieve desired material properties (such as to obtain high specific strength and high specific rigidity) and its wide range of applications. A large body of literature has been devoted to the modeling dynamics (vibrational behavior) of composite structures. However, most of the studies focus on simple geometries and boundary conditions such as beam (one-dimensional) and rectangular or circular plate (two-dimensional) models. And the methods developed using higher order modeling approaches are generally computationally inefficient. In this study, our aim is to develop a novel modeling approach that will enable accurately and (computationally) efficiently capturing the dynamics of different kinds of composite stuctures (as shown below) having arbitrary geometries and boundary conditions.
Numerical Simulation of (Assembled) StructuresIt is highly challenging to predict the dynamics of (assembled) structures that are too large or complex to be analyzed as a whole. To address this issue, we are developing a simulation framework (based on spectral Tchebychev approach) to analyze highly complex structures. To predict the dynamics of (assembled) structures, a substructuring algorithm will be applied to divide the complex structure into simpler geometries. Then, each of these simpler substructures will be solved using the ST method. Depending on the geometry of each substructure and also to increase the numerical efficiency, either a 1D-, 2D-, or 3D-ST approach will be implemented to obtain dynamic behavior. Lastly, to obtain the overall dynamics of the assembly structure, substructures will be combined via a component mode synthesis approach or a frequency based coupling technique.
Modeling and Experimentation of Dynamics of Mechanical Micromachining
Mechanical micromachining is an emerging technique for producing three-dimensional complex micro-scale geometries on a broad range of materials. In particular, it finds applications in biomedical and analytical devices, tribological surfaces, and medical devices. Effectively addressing the strict accuracy requirements of the micromachining application necessitates understanding and control of dynamic behavior of micromachining system, including motion actuators, spindle, and the tool, as well as their coupling with the mechanics of the material removal process. The dynamic behavior of the tool-holder-spindle-machine assembly, as reflected at cutting tip of a micro-tool, often determines the achievable process efficiency and quality. However, the existing (macro-scale) technique cannot be used to accurately model micromachining dynamics. Furthermore, new experimental techniques are needed to determine the speed-dependent modal characteristics of the ultra-high-speed spindles that are used during micromachining. The overarching objective of this research project is to derive and validate models for the micromachining process dynamics to enable prediction of micromachining process accuracy and efficiency (throughput).