Reconstruction and analysis of hybrid composite shells using meshless methods

G M S Bernardo,M A R Loja

doi:10.1007/s40091-017-0152-2

Abstract

The importance of focusing on the research of viable models to predict the behaviour of structures which may possess in some cases complex geometries is an issue that is growing in different scientific areas, ranging from the civil and mechanical engineering to the architecture or biomedical devices fields. In these cases, the research effort to find an efficient approach to fit laser scanning point clouds, to the desired surface, has been increasing, leading to the possibility of modelling as-built/as-is structures and components’ features. However, combining the task of surface reconstruction and the implementation of a structural analysis model is not a trivial task. Although there are works focusing those different phases in separate, there is still an effective need to find approaches able to interconnect them in an efficient way. Therefore, achieving a representative geometric model able to be subsequently submitted to a structural analysis in a similar based platform is a fundamental step to establish an effective expeditious processing workflow. With the present work, one presents an integrated methodology based on the use of meshless approaches, to reconstruct shells described by points’ clouds, and to subsequently predict their static behaviour. These methods are highly appropriate on dealing with unstructured points clouds, as they do not need to have any specific spatial or geometric requirement when implemented, depending only on the distance between the points. Details on the formulation, and a set of illustrative examples focusing the reconstruction of cylindrical and double-curvature shells, and its further analysis, are presented.

Highlights

During recent years, the use of 3D data acquisition devices has greatly increased resulting in the widespread dissemination of point clouds representations of sampled realworld objects
Achieving a representative geometric model able to be subsequently submitted to a structural analysis in a similar based platform is a fundamental step to establish an effective expeditious processing workflow
One presents an integrated methodology based on the use of meshless approaches, to reconstruct shells described by points’ clouds, and to subsequently predict their static behaviour

Summary

Introduction

The use of 3D data acquisition devices has greatly increased resulting in the widespread dissemination of point clouds representations of sampled realworld objects. Once the normals are computed, the position of the off-points created toward the direction of those normals can be calculated as follows: Fig. 1 Illustration of the off and on-surface points ðxNþi; yNþi; zNþiÞ 1⁄4 pi þ dnoi 1⁄4 ðxi þ dnoxi ; yi þ dnoyi ; zi þ dnozi Þ ðx2Nþi; y2Nþi; z2NþiÞ 1⁄4 pi À dnoi 1⁄4 ðxi À dnoxi ; yi À dnoyi ; zi À dnozi Þ; ð11Þ where d is the distance considered, between the in-surface points and the corresponding off-surface points, and noxi ;y;z, i = 1,...,n, denote the normals estimated for each coordinate axis This step consists on determining the value of the function f whose zero contour (isosurface f = 0) interpolates the point cloud data x1,...,n, and whose isosurface f = 1 and f = -1 interpolate xþnþ1;...;2n and xÀ2nþ1;...;3n, respectively, that is. The volume fraction of CNT can be expressed as follows:

CN wCN þ

F S ð31Þ

Conclusions