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Structural Size Optimization of External Fixation Device

Mešić Elmedin, Muminović Adil, Čolić Mirsad, Petrović Marin, Pervan Nedim

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 2

233-240

EN

Structural size optimization of a device for external bone fixation within a formed iterative hybrid optimization algorithm was presented in this paper. The optimization algorithm was in interaction with the algorithms for generative design and FEM analysis and completely integrated within CATIA CAD/CAM/CAE system. The initial model, representing the current design of the bone external fixation device Sarafix, was previously verified by experimental testing. The formed hybrid optimization algorithm was created as an integration of the global (SA method) and local (CG method) algorithm. The constraints of the optimization model are the clinical limitations of the interfragmentary displacements and the material strength. The optimized design has less weight, greater rigidity and less transverse interfragmentary displacements at the point of fracture compared to the current design.

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Noise Elimination of a Multi-tone Broadband Noise with Hybrid Helmholtz Mufflers Using a Simulated Annealing Method

Chiu M-C.

Archives of Acoustics

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2012

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Vol. 37, No. 4

489-498

EN

Noise control is essential in an enclosed machine room where the noise level has to comply with the occupational safety and health act. In order to overcome a pure tone noise with a high peak value that is harmful to human hearing, a traditional reactive muffler has been used. However, the traditional method for designing a reactive muffler has proven to be time-consuming and insufficient. In order to efficiently reduce the peak noise level, interest in shape optimization of a Helmholtz muffler is coming to the forefront. Helmholtz mufflers that deal with a pure tone have been adequately researched. However, the shape optimization of multi-chamber Helmholtz mufflers that deal with a broadband noise hybridized with multiple tones within a constrained space has been mostly ignored. Therefore, this study analyzes the sound transmission loss (STL) and the best optimized design for a hybrid Helmholtz muffler under a space- constrained situation. On the basis of the plane wave theory, the four-pole system matrix used to evaluate the acoustic performance of a multi-tone hybrid Helmholtz muffler is presented. Two numerical cases for eliminating one/two tone noises emitted from a machine room using six kinds of mufflers (muffler AF) is also introduced. To find the best acoustical performance of a space-constrained muffler, a numerical assessment using a simulated annealing (SA) method is adopted. Before the SA operation can be carried out, the accuracy of the mathematical model has been checked using the experimental data. Eliminating a broadband noise hybridized with a pure tone (130 Hz) in Case I reveals that muffler C composed of a one- chamber Helmholtz Resonator and a one-chamber dissipative element has a noise reduction of 54.9 (dB). Moreover, as indicated in Case II, muffler F, a two-chamber Helmholtz Resonator and a one-chamber dissipative element, has a noise reduction of 69.7 (dB). Obviously, the peak values of the pure tones in Case I and Case II are efficiently reduced after the muffler is added. Consequently, a successful approach in eliminating a broadband noise hybridized with multiple tones using optimally shaped hybrid Helmholtz mufflers and a simulated annealing method within a constrained space is demonstrated.

3

The optimal design of micro-punching die by using abductive and SA methods

Lin J.-Ch., Lee K.-S., Lin W.-S.

Archives of Computational Materials Science and Surface Engineering

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2009

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Vol. 1, nr 2

92-99

EN

Purpose: Punching process currently plays an important role in industrial mass production. The current study focuses on increasing accuracy, performance and extending service life of punches and dies. Optimizing the design of the punch and die has been a common topic for scholars. Design/methodology/approach: The input parameters (punching times, clearance) and output results (wear) were used to construct a training database. The abductive network formulation established a relationship between input parameters and output results. By using the abductive modeling technique, the complicated and uncertain relationships between the input and output variables can be formulated into a useful mathematical model. Once the abductive network model was constructed, the relationships between input and output parameters variables became available. A simulated annealing algorithm (SA) with a performance index was established to optimize this process and find the best result as compared with the actual experiment values. Findings: This study aims to establish the relationship between punching times, clearance and wear of micro punches using the abductive network, and to find relational model involving input parameters and output result of punching die in composite blanking processes. This model can be used to estimate wear between punch and die for industrial applications. Research limitations/implications: Setting up the relational expression of punching times, clearance and wear requires a well-established database covering sufficient relevant parameters and data. In training the database, it is helpful to establish a good relational model among punching parameters. Incorrect data will cause abnormal wear. As a result, the mathematics model is difficult to converge and the neural network will inaccurately predict wear. In addition, the punching die may be changed prematurely, which increases production costs. Delay in replacing a worn punching die can result in poor quality of products. Originality/value: As electronic production becomes increasingly smaller, the opportunity to use micro punches and dies will expand accordingly. This study established the relational expression of input and output, which can be used to correctly estimate any wear condition. This result is based on an abductive network and SA method.