Modeling and Optimizationof an Ultrasonic Setup Based on Combination of Finite Element Method and Mathematical Full Factorial Design

2011 ◽  
Vol 320 ◽  
pp. 553-558 ◽  
Author(s):  
Mohsen Ghahramani Nick ◽  
J. Akbari ◽  
Mohamad.R. Movahhedy ◽  
S.Mehdi Hoseini
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Objective Function ◽  
Factorial Design ◽  
Element Model ◽  
Optimization Method ◽  
Full Factorial Design ◽  
High Frequency Oscillation ◽  
Design Parameters ◽  
Full Factorial

Ultrasonic assisted machining (UAM) is an efficient nontraditional machining operation for brittle, hard-to-cut and poor-machinability materials. In UAM, high frequency oscillation in ultrasonic range at low amplitude is imposed on the workpiece or cutting tool. In most cases, the equipments that generates and transfers the vibration, have a complicated structure, and requires significant effort to achieve their optimum function. In this work, a mathematical model is developed and an optimization method is employed for design process. This makes it possible to achieve proper setup and reduce the amount of calculation. For this purpose, the combination of a two level full factorial design is performed with data that are obtained from finite element model(FEM)are used. Based on the mathematical model, an objective function is defined with the objective of maximizing the vibration amplitude at longitudinal resonance frequency of 22 kHz. Genetic algorithm is used to optimize the design parameters according to the defined objective function. The obtained results are shown just an error about 0.03 percent between FEM modal analysis and mathematical model answer. The advantages of the proposed optimization method in ultrasonic setup design in case of complicated geometries is discussed. Therefore optimization methods via FEM data could be regarded as an efficient approach for design of complicated structures.

A Computational Efficient Method to Assess the Sensitivity of Finite-Element Models: An Illustration With the Hemipelvis

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Dermot O'Rourke ◽  
Saulo Martelli ◽  
Murk Bottema ◽  
Mark Taylor
Keyword(s):  
Finite Element ◽  
Factorial Design ◽  
Surrogate Model ◽  
Computational Cost ◽  
Bone Geometry ◽  
Surrogate Models ◽  
Full Factorial Design ◽  
Fe Model ◽  
Kriging Surrogate Model ◽  
Full Factorial

Assessing the sensitivity of a finite-element (FE) model to uncertainties in geometric parameters and material properties is a fundamental step in understanding the reliability of model predictions. However, the computational cost of individual simulations and the large number of required models limits comprehensive quantification of model sensitivity. To quickly assess the sensitivity of an FE model, we built linear and Kriging surrogate models of an FE model of the intact hemipelvis. The percentage of the total sum of squares (%TSS) was used to determine the most influential input parameters and their possible interactions on the median, 95th percentile and maximum equivalent strains. We assessed the surrogate models by comparing their predictions to those of a full factorial design of FE simulations. The Kriging surrogate model accurately predicted all output metrics based on a training set of 30 analyses (R2 = 0.99). There was good agreement between the Kriging surrogate model and the full factorial design in determining the most influential input parameters and interactions. For the median, 95th percentile and maximum equivalent strain, the bone geometry (60%, 52%, and 76%, respectively) was the most influential input parameter. The interactions between bone geometry and cancellous bone modulus (13%) and bone geometry and cortical bone thickness (7%) were also influential terms on the output metrics. This study demonstrates a method with a low time and computational cost to quantify the sensitivity of an FE model. It can be applied to FE models in computational orthopaedic biomechanics in order to understand the reliability of predictions.

Model updating of finite element model using optimisation routine

2016 ◽  
Vol 88 (5) ◽  
pp. 665-675 ◽  
Author(s):  
Bimo Prananta ◽  
Toni Kanakis ◽  
Jos Vankan ◽  
Rien van Houten
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Objective Function ◽  
Mode Shape ◽  
Model Updating ◽  
Element Model ◽  
Design Parameters ◽  
Shape Error ◽  
Content Type ◽  
Small Aircraft

Purpose The present paper aims to describe the model updating of a small aircraft dynamic finite element model (FEM) to improve its agreement with ground vibration test (GVT) data. Design/methodology/approach An automatic updating method using an optimization procedure is carried out. Instead of using dedicated updating tools, the procedure is implemented using standard MSC/NASTRAN because of wide availability of the software in small aircraft industries. The objective function is defined to minimize the differences in the natural frequency and the differences in the mode shape between the analytical model and the GVT data. Provision has been made to include the quantification of confidence in both the GVT data and in the initial model. Parameter grouping is carried out to reduce the number of design parameters during the optimization process. Findings The optimization module of standard finite element (FE) software can be effectively used to reduce the differences between the GVT and the FEM in terms of frequency and mode shape satisfactorily. The strategy to define the objective function based on minimizing the mode shape error can reduce the improvement in the frequency error. The required user interference can be kept low. Originality/value The most important contribution of the present paper concerns the combination of strategies to define the objective function and selection of the parameters.

scholarly journals Multi-objective optimization of flexure hinge mechanism considering thermal–mechanical coupling deformation and natural frequency

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668791 ◽  
Author(s):  
Lufan Zhang ◽  
Xueli Li ◽  
Jiwen Fang ◽  
Zhili Long
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Element Model ◽  
Optimization Method ◽  
Design Parameters ◽  
Flexure Hinge ◽  
Multi Objective Optimization ◽  
Motion Platform ◽  
Mechanical Coupling ◽  
Multi Objective

Flexure hinge mechanism plays a key part in realization of terminal nano-positioning. The performance of flexure hinge mechanism is determined by its positioning design. Based on the actual working conditions, its finite element model is built and calculated in ANSYS. Moreover, change trends of deformation and natural frequency with positioning design parameters are revealed. And sensitivity analysis is performed for exploration response to these parameters. These parameters are used to build four objective functions. To solve it conveniently, the multi-objective optimization problem is transferred to the form of single-objective function with constraints. An optimal mechanism is obtained by an optimization method combining ANSYS with MATLAB. Finite element numerical simulation has been carried out to demonstrate the superiority of the optimal flexure hinge mechanism, and the superiority can be further verified by experiment. Measurements and tests have been conducted at varying accelerations, velocities, and displacements, to quantify and characterize the amount of acceleration responses obtained from flexure hinge mechanism before and after optimization. Both time- and frequency-domain analyses of experimental data show that the optimal flexure hinge mechanism has superior effectiveness. It will provide a basic for realizing high acceleration and high precision positioning of macro–micro motion platform.

scholarly journals OPTIMIZATION OF PCL-PEG-PCL TRIBLOCK COPOLYMER MICELLES AS HYDROPHOBIC DRUG CARRIER WITH A 22 FULL FACTORIAL DESIGN

2019 ◽  
pp. 42-47
Author(s):  
DEWI PATMAYUNI ◽  
T. N. SAIFULLAH SULAIMAN ◽  
ABDUL KARIM ZULKARNAIN
Keyword(s):  
Factorial Design ◽  
Triblock Copolymer ◽  
Drug Carrier ◽  
Entrapment Efficiency ◽  
Optimization Method ◽  
Full Factorial Design ◽  
Hydrophobic Drug ◽  
Copolymer Micelles ◽  
Optimum Formula ◽  
Full Factorial

Objective: This study aims to optimize PCL-PEG-PCL (PCEC) triblock copolymer micelles as a hydrophobic drug carrier, simvastatin (SV). Methods: PCEC triblock copolymer was prepared by the ring-opening polymerization method (ROP) with different ɛCL/PEG ratio (2 and 5). SV was incorporated into the PCEC triblock copolymer micelles with a concentration of 2.5 and 10 % w/w by the solvent evaporation method (film formation). The influence of the ɛCL/PEG ratio and concentration of SV effect on the responses particle size (PS), polydispersity index (PI) and entrapment efficiency (EE) was assessed using 22 full factorial design method. The test results were analyzed using Design-Expert software to obtain the optimum formula. Result: The selection of the optimum formula is based on the desirability value, the formula with the largest desirability value is chosen as the optimum formula. The results showed the optimum formula chosen had a desirability value of 0.860 consisting of a ɛCL/PEG ratio of 5 and SV concentration of 10 % w/w, with the PS, PI dan EE value was 322.1±3.51 nm, 0.471±0.09 and 87.08±1.17 %, respectively. Conclusion: The 22 full factorial design has been proven to be used as an optimization method to determine the optimum formula of SV-loaded PCEC triblock copolymer micelles with a good result of the PS, PI and EE responses.

Application of 32 Full Factorial Design and Desirability Function for Optimizing The Manufacturing Process for Directly Compressible Multi-Functional Co-Processed Excipient

2020 ◽  
Vol 17 (6) ◽  
pp. 523-539
Author(s):  
Jalpa Patel ◽  
Dhaval Mori
Keyword(s):  
Factorial Design ◽  
Spray Drying ◽  
Desirability Function ◽  
Full Factorial Design ◽  
Angle Of Repose ◽  
P Value ◽  
Independent Variables ◽  
Full Factorial ◽  
32 Full Factorial Design ◽  
Response Variables

Background: Developing a new excipient and obtaining its market approval is an expensive, time-consuming and complex process. Compared to that, the co-processing of already approved excipients has emerged as a more attractive option for bringing better characteristic excipients to the market. The application of the Design of Experiments (DoE) approach for developing co-processed excipient can make the entire process cost-effective and rapid. Objective: The aim of the present investigation was to demonstrate the applicability of the DoE approach, especially 32 full factorial design, to develop a multi-functional co-processed excipient for the direct compression of model drug - cefixime trihydrate using spray drying technique. Methods: The preliminary studies proved the significant effect of atomization pressure (X1) and polymer ratio (microcrystalline cellulose: mannitol - X2) on critical product characteristics, so they were selected as independent variables. The angle of repose, Carr’s index, Hausner’s ratio, tensile strength and Kuno’s constant were selected as response variables. Result: The statistical analysis proved a significant effect of both independent variables on all response variables with a significant p-value < 0.05. The desirability function available in Design Expert 11® software was used to prepare and select the optimized batch. The prepared co-processed excipient had better compressibility than individual excipients and their physical mixture and was able to accommodate more than 40 percent drug without compromising the flow property and compressibility. Conclusion: The present investigation successfully proved the applicability of 32 full factorial design as an effective tool for optimizing the spray drying process to prepare a multi-functional co-processed excipient.

Formulation of Extended-Release Beads of Lamotrigine Based on Alginate and Cassia fistula Seed Gum by QbD Approach

2020 ◽  
Vol 17 (5) ◽  
pp. 422-437
Author(s):  
Dixita Jain ◽  
Akshay Sodani ◽  
Swapnanil Ray ◽  
Pranab Ghosh ◽  
Gouranga Nandi
Keyword(s):  
Drug Release ◽  
Factorial Design ◽  
Extended Release ◽  
Polymer Concentration ◽  
Green Manufacturing ◽  
Full Factorial Design ◽  
Cassia Fistula ◽  
Negative Environmental Impact ◽  
Seed Gum ◽  
Full Factorial

Aim: This study was focused on the formulation of the multi-unit extended-release peroral delivery device of lamotrigine for better management of epilepsy. Background: The single-unit extended-release peroral preparations often suffer from all-or-none effect. A significant number of multi-unit delivery systems have been reported as a solution to this problem. But most of them are found to be composed of synthetic, semi-synthetic or their combination having physiological toxicity as well as negative environmental impact. Therefore, fabrication and formulation of multi-unit extended-release peroral preparations with natural, non-toxic, biodegradable polymers employing green manufacturing processes are being appreciated worldwide. Objective: Lamotrigine-loaded extended-release multi-unit beads have been fabricated with the incorporation of a natural polysaccharide Cassia fistula seed gum in calcium-cross-linked alginate matrix employing a simple green process and 23 full factorial design. Methods: The total polymer concentration, polymer ratio and [CaCl2] were considered as independent formulation variables with two different levels of each for the experiment-design. The extended-release beads were then prepared by the ionotropic gelation method using calcium chloride as the crosslinkerions provider. The beads were then evaluated for drug encapsulation efficiency and drug release. ANOVA of all the dependent variables such as DEE, cumulative % drug release at 2h, 5h, 12h, rate constant and dissolution similarity factor (f2) was done by 23 full factorial design using Design-Expert software along with numerical optimization of the independent variables in order to meet USP-reference release profile. Results: The optimized batch showed excellent outcomes with DEE of 84.7 ± 2.7 (%), CPR2h of 8.41± 2.96 (%), CPR5h of 36.8± 4.7 (%), CPR12h of 87.3 ± 3.64 (%) and f2 of 65.9. Conclusion: This approach of the development of multi-unit oral devices utilizing natural polysaccharides might be inspiring towards the world-wide effort for green manufacturing of sustained-release drug products by the QbD route.

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