Prediction of Nonlinear Damped Response of Large-Scale Blade Composite Structures

2013 ◽  
pp. 151-184
Author(s):  
Dimitrios I. Chortis
Keyword(s):  
Composite Structures ◽  
Large Scale

Enhanced Comprehension of the Continuous Fusion Bonding Process of Multi-Material Structures

2018 ◽  
Vol 939 ◽  
pp. 197-204 ◽  
Author(s):  
Tobias Reincke ◽  
Sven Hartwig ◽  
Klaus Dilger
Keyword(s):  
Composite Structures ◽  
Large Scale ◽  
Lightweight Design ◽  
Continuous Process ◽  
Peel Test ◽  
Roll Forming ◽  
Scale Production ◽  
Continuous Manufacturing ◽  
Fusion Bonding ◽  
Reinforced Thermoplastics

In comparison to monolithic composite structures, tailored multi-material structures offer high potential considering lightweight design approaches in combination with cost efficient manufacturing processes. Roll forming enables flexible large scale production of hybrid structures, due to the continuous manufacturing process as well as high degree of automation. The multi-material structures consist of steel sheets which are selectively reinforced by unidirectional carbon fibre reinforced thermoplastics (CFR-TP). In view of minimizing process steps and decreasing cycle times, both materials are joined by fusion bonding. Therefore, CFR-TP is heated above melting temperature of thermoplastic matrix and joined to the steel surface under defined pressure and time. However, joining of both materials within a continuous process is still challenging due to a lack in terms of process comprehension. Consequently, multi-material specimens were manufactured depending on various process parameters as temperature of either material or processing speed and tested mechanically by floating roller peel test for the evaluation of the adhesion between both materials. Furthermore, viscosity of matrix was determined and investigations of CFR-TP interface were performed by Fourier transform infrared spectroscopy. The results show the requirement of a defined CFR-TP temperature and the change in crystalline structure of the matrix in dependency of the processing.

A Vision-Based Gap Detection Method during the Placement of Large-Scale Composite Structures

2011 ◽  
Vol 186 ◽  
pp. 11-15
Author(s):  
Li Cao ◽  
Wen Chen ◽  
Jun Xiao
Keyword(s):  
Image Processing ◽  
Video Processing ◽  
Composite Structures ◽  
Large Scale ◽  
Low Cost ◽  
High Quality ◽  
Detection Technology ◽  
Gap Measurement ◽  
Automatic Placement ◽  
On Line

Video processing technology is regarded as a low-cost detection technology in complex environment. Because the placement layer is thin and the surface is complex that causes high detection error and high cost in laser measurement. Two problems must be solved before using it in large-scale composite structures automatic placement. One is to obtain the high-quality and stable image, and the other is to improve efficiency of image processing. In this paper, a method obtaining the high quality placement gap images was studied. It made use of the optical characteristics of composite material’s surface texture. And some parameters were determined by experiments. To reduce the calculation cost of image processing, a placement gap measurement method based on line scanning was also proposed here. The method was effective in our detection experiments on an actual workpiece.

scholarly journals Convectively Coupled Kelvin Waves: From Linear Theory to Global Models

2015 ◽  
Vol 73 (1) ◽  
pp. 407-428 ◽  
Author(s):  
Michael J. Herman ◽  
Zeljka Fuchs ◽  
David J. Raymond ◽  
Peter Bechtold
Keyword(s):  
Composite Structures ◽  
Large Scale ◽  
Kelvin Waves ◽  
Radiosonde Data ◽  
3D Analysis ◽  
Kelvin Wave ◽  
Scale Characteristics ◽  
Precipitation Anomalies ◽  
Convective Inhibition ◽  
Ecmwf Model

Abstract The authors analyze composite structures of tropical convectively coupled Kelvin waves (CCKWs) in terms of the theory of Raymond and Fuchs using radiosonde data, 3D analysis and reanalysis model output, and annual integrations with the ECMWF model on the full planet and on an aquaplanet. Precipitation anomalies are estimated using the NOAA interpolated OLR and TRMM 3B42 datasets, as well as using model OLR and rainfall diagnostics. Derived variables from these datasets are used to examine assumptions of the theory. Large-scale characteristics of wave phenomena are robust in all datasets and models where Kelvin wave variance is large. Indices from the theory representing column moisture and convective inhibition are also robust. The results suggest that the CCKW is highly dependent on convective inhibition, while column moisture does not play an important role.

scholarly journals Preparation of Nickel Nanoparticles by Direct Current Arc Discharge Method and Their Catalytic Application in Hybrid Na-Air Battery

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 684 ◽  
Author(s):  
Fengmei Su ◽  
Xuechao Qiu ◽  
Feng Liang ◽  
Manabu Tanaka ◽  
Tao Qu ◽  
...  
Keyword(s):  
Direct Current ◽  
Composite Structures ◽  
High Speed ◽  
Large Scale ◽  
Nickel Nanoparticles ◽  
Arc Discharge ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Air Battery ◽  
Discharge Method

Nickel nanoparticles were prepared by the arc discharge method. Argon and argon/hydrogen mixtures were used as plasma gas; the evaporation of anode material chiefly resulted in the formation of different arc-anode attachments at different hydrogen concentrations. The concentration of hydrogen was fixed at 0, 30, and 50 vol% in argon arc, corresponding to diffuse, multiple, and constricted arc-anode attachments, respectively, which were observed by using a high-speed camera. The images of the cathode and anode jets were observed with a suitable band-pass filter. The relationship between the area change of the cathode/anode jet and the synchronous voltage/current waveform was studied. By investigating diverse arc-anode attachments, the effect of hydrogen concentration on the features of nickel nanoparticles were investigated, finding that 50 vol% H2 concentration has high productivity, fine crystallinity, and appropriate size distribution. The synthesized nickel nanoparticles were then used as catalysts in a hybrid sodium–air battery. Compared with commercial a silver nanoparticle catalyst and carbon black, nickel nanoparticles have better electrocatalytic performance. The promising electrocatalytic activity of nickel nanoparticles can be ascribed to their good crystallinity, effective activation sites, and Ni/NiO composite structures. Nickel nanoparticles prepared by the direct current (DC) arc discharge method have the potential to be applied as catalysts on a large scale.

Large-scale three-dimensional anisotropic topology optimization of variable-axial lightweight composite structures

2021 ◽  
pp. 1-15
Author(s):  
Yuqing Zhou ◽  
Tsuyoshi Nomura ◽  
Enpei Zhao ◽  
Kazuhiro Saitou
Keyword(s):  
Topology Optimization ◽  
Composite Structures ◽  
Large Scale ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Optimization Method ◽  
Optimized Design ◽  
Adaptive Meshing ◽  
Design Synthesis ◽  
Fiber Placement

Abstract Variable-axial fiber-reinforced composites allow for local customization of fiber orientation and thicknesses. Despite their significant potential for performance improvement over the conventional multiaxial composites and metals, they pose challenges in design optimization due to the vastly increased design freedom in material orientations. This paper presents an anisotropic topology optimization method for designing large-scale, 3D variable-axial lightweight composite structures subject to multiple load cases. The computational challenges associated with large-scale 3D anisotropic topology optimization with extremely low volume fraction are addressed by a tensor-based representation of 3D orientation that would avoid the 2π periodicity of angular representations such as Euler angles, and an adaptive meshing scheme, which, in conjunction with PDE regularization of the density variables, refines the mesh where structural members appear and coarsens where there is void. The proposed method is applied to designing a heavy-duty drone frame subject to complex multi-loading conditions. Finally, the manufacturability gaps between the optimized design and the fabrication-ready design for Tailored Fiber Placement (TFP) is discussed, which motivates future work toward a fully-automated design synthesis.

scholarly journals Stereological Estimation of Orientation Distribution of Generalized Cylinders from a Unique 2D Slice

2013 ◽  
Vol 19 (6) ◽  
pp. 1678-1687 ◽  
Author(s):  
Jean-Pierre Da Costa ◽  
Stefan Oprean ◽  
Pierre Baylou ◽  
Christian Germain
Keyword(s):  
Cross Sections ◽  
Composite Structures ◽  
Large Scale ◽  
Fibrous Composite ◽  
Three Dimensional ◽  
Synthetic Data ◽  
Inequality Constraints ◽  
Orientation Distribution ◽  
Industrial Applications ◽  
Cost Constraints

AbstractThough three-dimensional (3D) imaging gives deep insight into the inner structure of complex materials, the stereological analysis of 2D snapshots of material sections is still necessary for large-scale industrial applications for reasons related to time and cost constraints. In this paper, we propose an original framework to estimate the orientation distribution of generalized cylindrical structures from a single 2D section. Contrary to existing approaches, knowledge of the cylinder cross-section shape is not necessary. The only requirement is to know the area distribution of the cross-sections. The approach relies on minimization of a least squares criterion under linear equality and inequality constraints that can be solved with standard optimization solvers. It is evaluated on synthetic data, including simulated images, and is applied to experimental microscopy images of fibrous composite structures. The results show the relevance and capabilities of the approach though some limitations have been identified regarding sensitivity to deviations from the assumed model.

On a digital wireless impact-monitoring network for large-scale composite structures

2014 ◽  
Vol 23 (8) ◽  
pp. 085007 ◽  
Author(s):  
Shenfang Yuan ◽  
Hanfei Mei ◽  
Lei Qiu ◽  
Yuanqiang Ren
Keyword(s):  
Composite Structures ◽  
Large Scale ◽  
Monitoring Network ◽  
Impact Monitoring

Large-Scale Three-Dimensional Anisotropic Topology Optimization of Variable-Axial Composite Structures

2020 ◽  
Author(s):  
Yuqing Zhou ◽  
Tsuyoshi Nomura ◽  
Enpei Zhao ◽  
Wei Zhang ◽  
Kazuhiro Saitou
Keyword(s):  
Topology Optimization ◽  
Composite Structures ◽  
Large Scale ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Optimized Design ◽  
Adaptive Meshing ◽  
Design Synthesis ◽  
Fiber Placement ◽  
Future Work

Abstract Variable-axial fiber-reinforced composites allow for local customization of fiber orientation and thicknesses. Despite their significant potential for performance improvement over the conventional multiaxial composites and metals, they pose challenges in design optimization due to the vastly increased design freedom in material orientations. This paper presents an anisotropic topology optimization (TO) method for designing large-scale, 3D variable-axial composite structures. The computational challenge for large-scale 3D TO with extremely low volume fraction is addressed by a tensor-based representation of 3D orientation that would avoid the 2π periodicity of angular representation such as Eular angles, and an adaptive meshing scheme, which, in conjunction with PDE regularization of the density variables, refines the mesh where structural members appear and coarsens where there is void. The proposed method is applied to designing a heavy-duty drone frame subject to complex multi-loading conditions. Finally, the manufacturability gaps between the optimized design and the fabrication-ready design for Tailored Fiber Placement (TFP) is discussed, which motivates future work toward fully-automated design synthesis.

Sign in / Sign up

Export Citation Format

Share Document