Yujie Guo
Delft University of Technology
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Featured researches published by Yujie Guo.
Computers & Mathematics With Applications | 2015
Yujie Guo; Martin Ruess
Computer-aided design-based NURBS surfaces form the basis of isogeometric shell analysis which exploits the smoothness and higher continuity properties of NURBS to derive a suitable analysis model in an isoparametric sense. Equipped with higher order approximation capabilities the used NURBS functions focus increasingly on rotation-free shell elements which are considered to be difficult in the traditional finite element framework. The rotation-free formulation of shell elements is elegant and efficient but demands special care to enforce reliably essential translational and rotational boundary conditions which is even more challenging in the case of trimmed boundaries as common in CAD models. We propose a Nitsche-based extension of the Kirchhoff-Love theory to enforce weakly essential boundary conditions of the shell. We apply our method to trimmed and untrimmed NURBS structures and illustrate a good performance of the method with benchmark test models and a shell model from engineering practice. With an extension of the formulation to a weak enforcement of coupling constraints we are able to handle CAD-derived trimmed multi-patch NURBS models for thin shell structures.
56th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference | 2015
Yujie Guo; Martin Ruess
Shell structures are widely used in aerospace industry. They are ideal candidates for the isogeometric analysis paradigm profiting from the smoothness, the higher order approximation and higher continuity properties of NURBS. For the modeling of complex shell structures which need to be assembled from multiple patches, the bending stiffness should be maintained across patch interfaces. We propose a variationally consistent weak coupling method for thin-walled shell patches. The method overcomes the need for C1 continuity along the patch interface and even allows a blended coupling of shells based on different mathematical models, e.g. Kirchhoff-Love and solid-like shell models. The results confirm a high level of accuracy and reveal the method’s potential for complex multi-patch IGA modeling. It further opens the door for the coupling of laminated composites belonging to different lamina theories.
54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference | 2013
Yujie Guo; Attila P. Nagy; Zafer Gürdal
The isogeometric paradigm is used to develop a displacement-based layerwise model for thick composite laminates. Layerwise theories provide accurate prediction of the threedimensional stress state that is of prime importance in structural design. This is in sharp contrast to the class of equivalent single layer theories that yield no or inaccurate information about the transverse stress components. The key idea of layerwise methods is to impose different continuity requirements on the functions of approximation in the inplane and out-of-plane directions. While maintaining higher-order continuity of the basis functions within a single layer is desirable, continuity of the transverse stresses, dictated by the equilibrium consideration, requires C-continuous basis at the interface of adjacent plies. Contrary to previously introduced approaches, the latter conditions can be naturally facilitated through conscious use of isogeometric refinement schemes. The details of the proposed approach are presented in a non-uniform rational B-spline based isogeometric framework. Combining the introduced layerwise and equivalent single layer theories, a multiple model analysis is presented. The aim is to demonstrate the use of the different models within predefined regions of a single laminate and to study the influence of the size of the layerwise region on the accuracy of transverse stresses. Finally, the multi model analysis concept is employed to simulate laminates with existing delaminations. The proposed models are verified considering laminated composite plate under cylindrical bending. The numerical results confirm the accuracy of the proposed models. The displacement and stresses are compared to the existing solutions and good agreement is found. It is also shown that the isogeometric layerwise approach outperforms its traditional Lagrange polynomial-based finite element counterpart on a per degree of freedom basis.
Computer Methods in Applied Mechanics and Engineering | 2015
Yujie Guo; Martin Ruess
Composite Structures | 2014
Yujie Guo; Attila P. Nagy; Zafer Gürdal
Composite Structures | 2014
Yujie Guo; Martin Ruess; Zafer Gürdal
Computational Mechanics | 2017
Yujie Guo; Martin Ruess; Dominik Schillinger
Composite Structures | 2015
Yujie Guo; Martin Ruess
Mechanism and Machine Theory | 2015
Nannan Xu; Wencheng Tang; Yongjiang Chen; Dafei Bao; Yujie Guo
Composite Structures | 2017
Yujie Guo