Correlating low energy impact damage with changes in modal parameters: diagnosis tools and FE validation

This paper presents a basic experimental technique and simplified FE based models for the detection, localization and quantification of impact damage in composite beams around the BVID level. Detection of damage is carried out by shift in modal parameters. Localization of damage is done by a topology optimization tool which showed that correct damage locations can be found rather efficiently for low-level damage. The novelty of this paper is that we develop an All In One (AIO) package dedicated to impact identification by modal analysis. The damaged zones in the FE models are updated by reducing the most sensitive material property in order to improve the experimental/numerical correlation of the frequency response functions. These approximate damage models(in term of equivalent rigidity) give us a simple degradation factor that can serve as a warning regarding structure safety

Scanning X-ray nanodiffraction: from the experimental approach towards spatially resolved scattering simulations

An enhancement on the method of X-ray diffraction simulations for applications using nanofocused hard X-ray beams is presented. We combine finite element method, kinematical scattering calculations, and a spot profile of the X-ray beam to simulate the diffraction of definite parts of semiconductor nanostructures. The spot profile could be acquired experimentally by X-ray ptychography. Simulation results are discussed and compared with corresponding X-ray nanodiffraction experiments on single SiGe dots and dot molecules

Multilevel framework for optimization of lightweight structures

Optimization of aerospace and lightweight structures, such as aircraft wings, is typically best carried out via a multilevel process. This becomes necessary owing to the complexity of the structure and potentially very large numbers of design variables. While more conventional analysis and design procedures are often based on the computationally expensive finite element method, specialist software, such as the ‘exact’ strip program VICONOPT, provides faster and more efficient alternatives for structural components such as wing panels. With ever-increasing computational power, different software solutions can be integrated by means of robust and easy-to-use interfaces, allowing the user to benefit from more versatile optimization environments. The computer program Viconopt MLO establishes a multilevel framework for optimization by interfacing the panel analysis and design software VICONOPT and the finite element software MSC/NASTRAN. In this paper the underlying principles of the optimization procedure in Viconopt MLO are described, and the software's capability is demonstrated through the optimization of a composite aircraft wing