An efficient design method for multi-material bolted joints used in the railway industry

2011 ◽  
Vol 94 (1) ◽  
pp. 246-252 ◽  
Author(s):  
G. Catalanotti ◽  
P.P. Camanho ◽  
P. Ghys ◽  
A.T. Marques
Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6651
Author(s):  
Zhaonian Wang ◽  
Jiangbing Du ◽  
Weihong Shen ◽  
Jiacheng Liu ◽  
Zuyuan He

Chromatic dispersion engineering of photonic waveguide is of great importance for Photonic Integrated Circuit in broad applications, including on-chip CD compensation, supercontinuum generation, Kerr-comb generation, micro resonator and mode-locked laser. Linear propagation behavior and nonlinear effects of the light wave can be manipulated by engineering CD, in order to manipulate the temporal shape and frequency spectrum. Therefore, agile shapes of dispersion profiles, including typically wideband flat dispersion, are highly desired among various applications. In this study, we demonstrate a novel method for agile dispersion engineering of integrated photonic waveguide. Based on a horizontal double-slot structure, we obtained agile dispersion shapes, including broadband low dispersion, constant dispersion and slope-maintained linear dispersion. The proposed inverse design method is objectively-motivated and automation-supported. Dispersion in the range of 0–1.5 ps/(nm·km) for 861-nm bandwidth has been achieved, which shows superior performance for broadband low dispersion. Numerical simulation of the Kerr frequency comb was carried out utilizing the obtained dispersion shapes and a comb spectrum for 1068-nm bandwidth with a 20-dB power variation was generated. Significant potential for integrated photonic design automation can be expected.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Young-Gon Kim ◽  
Kang Wook Kim

A clear and efficient design method for ultra-wideband microstrip-to-suspended stripline transition, which is based on the analytical expressions of the whole transitional structure, is presented. The conformal mapping is applied to obtain the characteristic impedance of the transitional structure within 2.85% accuracy as compared with the EM-simulation results. The transition is designed to provide broadband impedance matching and smooth field conversion. The implemented transition performs less than 0.6 dB insertion loss per transition for frequencies up to 30 GHz.


Author(s):  
Xin Shen ◽  
Xiao-cheng Zhu ◽  
Zhao-hui Du

This paper describes an optimization method for the design of horizontal axis wind turbines using the lifting surface method as the performance prediction model and a genetic algorithm for optimization. The aerodynamic code for the design method is based on the lifting surface method with a prescribed wake model for the description of the wake. A micro genetic algorithm handles the decision variables of the optimization problem such as the chord and twist distribution of the blade. The scope of the optimization method is to achieve the best trade off of the following objectives: maximum of annual energy production and minimum of blade loads including thrust and blade rood flap-wise moment. To illustrate how the optimization of the blade is carried out the procedure is applied to NREL Phase VI rotor. The result shows the optimization model can provide a more efficient design.


1988 ◽  
Vol 110 (3) ◽  
pp. 255-262 ◽  
Author(s):  
A. K. Roy ◽  
S. W. Tsai

A simple and efficient design method for thick composite cylinders is presented. Micromechanics and macromechanics are integrated by simple relations and the integrated micro and macromechanics approach has been adopted to enable the designers to instantly study the sensitivity of the micromechanical variables on the final design. The stress analysis is based on 3-dimensional elasticity by considering the cylinder in the state of generalized plane strain. The analysis for both open-ended (pipes) and closed-ended (pressure vessels) cylinders subjected to internal and external pressures and axial load is presented. The failure of the cylinders is predicted by using a 3-dimensional quadratic failure criterion. A degradation model is used to calculate burst pressures and the calculated burst pressures agree very well with the available experimental results, for both thin and thick cylinders. In optimizing multilayer cylinders, the 3-D quadratic criterion enables one to obtain the optimal layer sequence very easily. It is found that the layer sequence is very critical in optimizing, in particular, thick cylinders. In addition, the design parameters and material use efficiency of multilayer closed cylinders subjected to internal pressure have also been studied.


2020 ◽  
Vol 87 (11) ◽  
Author(s):  
Raman Goyal ◽  
Robert E. Skelton ◽  
Edwin A. Peraza Hernandez

Abstract Tensegrities are prestressable trusses that have been proven to support various load distributions with minimum mass. This article presents a novel efficient method for designing lightweight tensegrities under local and global failure constraints. Local failure includes buckling and material yielding of individual members in the tensegrity. Global failure refers to global buckling of the tensegrity, where it loses stability without undergoing local failure at its individual members. The formulation and numerical approach to determine the critical global buckling forces and mode shapes of tensegrities with arbitrary shape and topology are first provided. Next, the design method considering local and global failure is presented, which starts with the local sizing of the member areas of the given tensegrity for the prevention of local failure. The method then determines the dominant failure mode by comparing the external forces and the critical global buckling force of the locally sized structure. If the critical global buckling force is larger than the external force, the dominant mode is a local failure and the locally sized design is returned as the minimum mass design. Conversely, if global failure is the dominant mode, different global reinforcement approaches are applied to raise the critical buckling force of the structure until it matches the external force, preventing global buckling. These reinforcement approaches include increasing the areas of the members and increasing the prestress in the tensegrity. Representative examples are provided to demonstrate the effectiveness of the design method considering box and T-bar tensegrities.


Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 531
Author(s):  
Yun Seon Do

Nano-structure-based color technologies have been reported as alternatives for conventional pigment- or dye-based color filters due to their simple design methods and durable characteristics. Since structure-based optical resonances accompany multiple resonance modes, spectral selectivity could be degraded. In this work, a simple and effective design of a plasmonic color filter that combines the plasmonic filter with one-dimensional photonic crystals. The introduced photonic crystal provides a photonic band gap, and it helps in suppressing the undesirable transmission peaks of the plasmonic color filter that originates from higher order resonance modes. Finally, the proposed design achieves high color purity. In addition, the simplicity of the design makes it both suitable for large-area fabrication and cost effective. This work is expected to provide a practical alternative to traditional color filters.


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