Computational Simulations of Vertebral Body for Optimal Instrumentation Design

2012 ◽  
Vol 6 (2) ◽  
Author(s):  
F. Casesnoves
Keyword(s):  
Experimental Data ◽  
Engineering Design ◽  
Vertebral Body ◽  
Technical Difficulty ◽  
Regions Of Interest ◽  
Computational Method ◽  
Mechanical Forces ◽  
Computational Simulations ◽  
Large Sets ◽  
Fitting Model

The engineering design of surgical instrumentation to exert forces and torques/moments on bones during operations constitutes a rather difficult task. This technical difficulty is caused mainly by the natural, pathological, and individual irregularities of the human bone morphologies and surfaces. Usually, mechanical forces are applied on determined parts of bone surfaces, so-called regions of interest (ROIs). We describe a computational method (CAD) to digitalize, simulate, and fit mathematically the anterior vertebral body morphometric. Based on experimental data from 17 cadaveric specimens, large sets of surface digital points were generated. Complete anterior vertebral body morphologies were visualized and analyzed with subroutines, which are initially used to select these natural ROIs. Subsequently, an optimized fitting model was implemented for the ROIs. 3D surface equations of the anterior vertebral body (L3, L4, L5, and S1) were determined. Statistics and determination coefficients which define the error boundaries and goodness of the model, were calculated and mathematically analyzed. A bioengineering application is the use of these equations for the industrial design of an innovative vertebral distractor. The device separates two adjacent vertebrae in parallel, and minimizes the force to carry out the surgical maneuver.

scholarly journals Computational Simulations of the Anterior Vertebral Surface for Optimal Surgical Instrumentation Design

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Francisco Casesnoves
Keyword(s):  
Vertebral Body ◽  
Design Method ◽  
Computational Design ◽  
Human Bone ◽  
Mechanical Forces ◽  
Grid Data ◽  
Statistical Parameters ◽  
Surgical Instrumentation ◽  
The Individual ◽  
Fitting Model

The engineering design of surgical instrumentation to apply mechanical forces and linear moments on the human bones during the operations constitutes a rather difficult task. This is due both to the natural and pathological irregularities of the human bone morphology and surfaces and also to the individual variations from one patient to another. Usually, the forces are applied by the surgeon only on a determined part of the bone surfaces. This paper describes an innovative computational design method to digitalize, simulate, and fit mathematically the anterior vertebral body facet. We used real experimental data from 17 human cadaveric specimens to get and store a large amount of numerical surface digital values. The complete anterior vertebral body side was visualized and analyzed with grid data Subroutine, which was also used first to select the so-called natural regions of interest (ROIs). These ROIs correspond to those parts of the surface in contact with the surgical instrumentation, where the mechanical forces are applied. Subsequently, a numerical mathematical fitting-model was implemented for these ROIs. This was carried out with the development of a 3D geometrical least-squares optimization algorithm and appropriate software designed according to the proper numerical method selected. In doing so, the 3D superficies equations of the anterior vertebral body (L3, L4, L5, and S1) were determined after these fittings were mathematically checked as appropriate. Statistical parameters and determination coefficients that define the error boundaries and the goodness of this optimal fitting-model were calculated and NURBS error data in similar studies were commented. It was proven that the principal source of error was the micro- and macro-irregularities of human bone facets. The final surface equations, and their geodesics, were used to obtain accurate data for the spinal surgery instrumentation manufacturing. The industrial bioengineering result was the application of these equations for the design of a new spinal vertebral surgical distractor. This innovative distractor separates two adjacent vertebrae while keeping them parallel. That is, at their natural inclination, avoiding hammering the vertebrae to make the intervertebral space wider. The device mechanics also minimizes the necessary force to be carried out by the surgeon during the operation.

Prediction of Cavitation Inception Within Regions of Flow Separation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Turbulent Flow ◽  
Flow Separation ◽  
Computational Method ◽  
Average Flow ◽  
Cavitation Inception ◽  
The Core ◽  
Good Agreement

Cavitation within regions of flow separation appears in drifting vortices. A two-part computational method is employed for prediction of cavitation inception number there. The first part is an analysis of the average flow in separation regions without consideration of an impact of vortices. The second part is an analysis of equilibrium of the bubble within the core of a vortex located in the turbulent flow of known average characteristics. Computed cavitation inception numbers for axisymmetric flows are in the good agreement with the known experimental data.

A lower confidence bounding approach based on the coefficient of variation for expensive global design optimization

2019 ◽  
Vol 36 (3) ◽  
pp. 830-849 ◽  
Author(s):  
Ji Cheng ◽  
Ping Jiang ◽  
Qi Zhou ◽  
Jiexiang Hu ◽  
Tao Yu ◽  
...  
Keyword(s):  
Design Optimization ◽  
Engineering Design ◽  
Computational Efficiency ◽  
Coefficient Of Variation ◽  
Computational Simulations ◽  
Exploration And Exploitation ◽  
Content Type ◽  
Degree Of Dispersion ◽  
Lower Confidence ◽  
Engineering Design Optimization

PurposeEngineering design optimization involving computational simulations is usually a time-consuming, even computationally prohibitive process. To relieve the computational burden, the adaptive metamodel-based design optimization (AMBDO) approaches have been widely used. This paper aims to develop an AMBDO approach, a lower confidence bounding approach based on the coefficient of variation (CV-LCB) approach, to balance the exploration and exploitation objectively for obtaining a global optimum under limited computational budget.Design/methodology/approachIn the proposed CV-LCB approach, the coefficient of variation (CV) of predicted values is introduced to indicate the degree of dispersion of objective function values, while the CV of predicting errors is introduced to represent the accuracy of the established metamodel. Then, a weighted formula, which takes the degree of dispersion and the prediction accuracy into consideration, is defined based on the already-acquired CV information to adaptively update the metamodel during the optimization process.FindingsTen numerical examples with different degrees of complexity and an AIAA aerodynamic design optimization problem are used to demonstrate the effectiveness of the proposed CV-LCB approach. The comparisons between the proposed approach and four existing approaches regarding the computational efficiency and robustness are made. Results illustrate the merits of the proposed CV-LCB approach in computational efficiency and robustness.Practical implicationsThe proposed approach exhibits high efficiency and robustness in engineering design optimization involving computational simulations.Originality/valueCV-LCB approach can balance the exploration and exploitation objectively.

Optimal Calculation Method of Eccentric Bearing Capacity of Concrete-Filled Steel Tube Short Columns

2012 ◽  
Vol 238 ◽  
pp. 666-668
Author(s):  
Jian Wei Zhang ◽  
Xing Jie Kuang ◽  
Wei Feng Bai ◽  
Juan Wang
Keyword(s):  
Experimental Data ◽  
Bearing Capacity ◽  
Engineering Design ◽  
Calculation Method ◽  
Steel Tube ◽  
Concrete Filled Steel Tube ◽  
Short Columns ◽  
Optimal Calculation

The currently formulae with many coefficients are too complicated to calculate the bearing capacity of concrete-filled steel tube (CFST) short columns. In this paper, an optimal calculation method was proposed for calculating the eccentric bearing capacity of CFST short columns by means of mechanical derivation. Additionally, the calculating results are compared with experimental data. It is shown that the optimal calculating formulae are highly accurate and easily applicable in engineering design.

Applicability of Net-Section Collapse Load Approach to Maximum Load Predictions of Multiple Circumferential Cracked Pipes: Numerical Study

2015 ◽  
Author(s):  
Myeong-Woo Lee ◽  
Seung-Jae Kim ◽  
So-Dam Lee ◽  
Jun-Young Jeon ◽  
Yun-Jae Kim
Keyword(s):  
Experimental Data ◽  
Numerical Method ◽  
Test Data ◽  
Numerical Study ◽  
Maximum Load ◽  
Load Carrying Capacity ◽  
Collapse Load ◽  
Crack Geometry ◽  
Large Sets ◽  
Load Carrying

To estimate maximum load-carrying capacity of pipes with multiple circumferential cracks, the net-section collapse load approach has been proposed. Although the proposed method has been validated against pipe test data, experimental data are quite limited due to large sets of variables to be considered. In this paper, a numerical method is proposed to generate virtual pipe test data with wide ranges of crack geometry and interspacing. To get confidence of the proposed numerical method, it is firstly applied to simulate existing 4-inch diameter schedule 80 pipes with two circumferential cracks. Predicted maximum loads agree well with experimental data. Then the proposed method is applied to generate maximum loads for wider ranges of crack geometry and loading conditions. It is found that the net-section collapse load approach works well for all cases considered.

scholarly journals The interplay of stiffness and force anisotropies drives embryo elongation

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Thanh Thi Kim Vuong-Brender ◽  
Martine Ben Amar ◽  
Julien Pontabry ◽  
Michel Labouesse
Keyword(s):  
Experimental Data ◽  
Material Properties ◽  
Myosin Ii ◽  
Mechanical Forces ◽  
Cell Behaviour ◽  
Cortical Tension ◽  
Actin Cortex ◽  
Stiffness Anisotropy ◽  
Spatiotemporal Changes ◽  
Tissue Material

The morphogenesis of tissues, like the deformation of an object, results from the interplay between their material properties and the mechanical forces exerted on them. The importance of mechanical forces in influencing cell behaviour is widely recognized, whereas the importance of tissue material properties, in particular stiffness, has received much less attention. Using Caenorhabditis elegans as a model, we examine how both aspects contribute to embryonic elongation. Measuring the opening shape of the epidermal actin cortex after laser nano-ablation, we assess the spatiotemporal changes of actomyosin-dependent force and stiffness along the antero-posterior and dorso-ventral axis. Experimental data and analytical modelling show that myosin-II-dependent force anisotropy within the lateral epidermis, and stiffness anisotropy within the fiber-reinforced dorso-ventral epidermis are critical in driving embryonic elongation. Together, our results establish a quantitative link between cortical tension, material properties and morphogenesis of an entire embryo.

scholarly journals Methodic for evaluating the performance of a continuous welded track according to the criterion of compliance of the actual rail fastening temperature with the standardized value

2021 ◽  
Vol 80 (6) ◽  
pp. 327-333
Author(s):  
G. M. Volokhov ◽  
S. V. Chunin ◽  
A. V. Ushanov
Keyword(s):  
Experimental Data ◽  
Natural Frequency ◽  
Safety Evaluation ◽  
Field Tests ◽  
Element Model ◽  
Longitudinal Force ◽  
Computational Method ◽  
Actual Temperature ◽  
Current Assessment ◽  
The Given

Problem of safety evaluation of continuous welded track operation is considered. A comparative analysis of the current assessment methods is carried out and a method is proposed for identifying dangerous track sections according to the criterion of compliance of the actual rail fastening temperature with the standardized one. Under the actual fxing temperature in the article, the temperature of the rail is taken at which, as a result of its thermal expansion or contraction, a zero value of the longitudinal force is formed in it. A method is presented for calculating the actual temperature of rail fastening using the dependence of the natural frequency of rail vibrations on the applied longitudinal force, which was obtained by the computational method using the fnite element model of the track section created by the authors by means of modal calculations for various values of the longitudinal force applied to the rail. Its verifcation was carried out using experimental data obtained as a result of testing at a specialized stand. The method of tests carried out on the stand and section of the continuous track of the Ozerskaya branch of the Moscow Railway is described, which consists in determining the natural frequency of the first mode of rail vibration at different values of the longitudinal force, and in the case of field tests at different values of the rail temperature. The calculation of the actual temperature of rail fastening is given on the example of a section of a continuous-welded track of the Ozerskaya branch of the Moscow railway. It was found that the temperature of rail fastening on the investigated section corresponds to the normative for the given region.

Selection of Fitting Models of the Moisture Content for Paper Honeycomb Sandwich Panel

2012 ◽  
Vol 200 ◽  
pp. 58-61
Author(s):  
Dong Mei Wang
Keyword(s):  
Experimental Data ◽  
Moisture Content ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Influence Of Temperature ◽  
Honeycomb Sandwich ◽  
Best Fitting ◽  
Paper Honeycomb ◽  
Fitting Model ◽  
Selection Of

The influence of temperature and relative humidity on the moisture content of paper honeycomb sandwich panels was studied. The moisture content of paper honeycomb sandwich panels was fitted by three mathematical models. The fitting results were evaluated by experimental data, and the best fitting model and its parameters were determined. The results indicate that in three models, the GAB (Guggenheim, Anderson and De Boer) model is the best suited to predict the moisture content of paper honeycomb sandwich panels in different temperature and humidity conditions.

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