scholarly journals Spreading out Muscle Mass within a Hill-Type Model: A Computer Simulation Study

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Michael Günther ◽  
Oliver Röhrle ◽  
Daniel F. B. Haeufle ◽  
Syn Schmitt
Keyword(s):  
Design Parameters ◽  
Type Model ◽  
Internal Mass ◽  
Response Scale ◽  
First Order ◽  
Contraction Velocity ◽  
Hyperbolic Relation ◽  
Small Muscle ◽  
Internal Inertia ◽  
Contraction Dynamics

It is state of the art that muscle contraction dynamics is adequately described by a hyperbolic relation between muscle force and contraction velocity (Hill relation), thereby neglecting muscle internal mass inertia (first-order dynamics). Accordingly, the vast majority of modelling approaches also neglect muscle internal inertia. Assuming that such first-order contraction dynamics yet interacts with muscle internal mass distribution, this study investigates two questions: (i) what is the time scale on which the muscle responds to a force step? (ii) How does this response scale with muscle design parameters? Thereto, we simulated accelerated contractions of alternating sequences of Hill-type contractile elements and point masses. We found that in a typical small muscle the force levels off after about 0.2 ms, contraction velocity after about 0.5 ms. In an upscaled version representing bigger mammals' muscles, the force levels off after about 20 ms, and the theoretically expected maximum contraction velocity is not reached. We conclude (i) that it may be indispensable to introduce second-order contributions into muscle models to understand high-frequency muscle responses, particularly in bigger muscles. Additionally, (ii) constructing more elaborate measuring devices seems to be worthwhile to distinguish viscoelastic and inertia properties in rapid contractile responses of muscles.

Flight Control of a Twin-Rotor Type Model Helicopter Based on First-Order Approximate Linearization

2014 ◽  
Vol 134 (9) ◽  
pp. 1269-1270 ◽  
Author(s):  
Hiroki Noma ◽  
Shun Tanabe ◽  
Takao Sato ◽  
Nozomu Araki ◽  
Yasuo Konishi
Keyword(s):  
Flight Control ◽  
Type Model ◽  
First Order ◽  
Model Helicopter ◽  
Approximate Linearization ◽  
Twin Rotor ◽  
Rotor Type

scholarly journals Design optimization of vehicle asynchronous motors based on fractional harmonic response analysis

2021 ◽  
Vol 12 (1) ◽  
pp. 689-700
Author(s):  
Ao Lei ◽  
Chuan-Xue Song ◽  
Yu-Long Lei ◽  
Yao Fu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequency ◽  
Asynchronous Motor ◽  
Element Model ◽  
Design Parameters ◽  
Response Analysis ◽  
Harmonic Response ◽  
First Order ◽  
Harmonic Response Analysis

Abstract. To make vehicles more reliable and efficient, many researchers have tried to improve the rotor performance. Although certain achievements have been made, the previous finite element model did not reflect the historical process of the motor rotor well, and the rigidity and mass in rotor optimization are less discussed together. This paper firstly introduces fractional order into a finite element model to conduct the harmonic response analysis. Then, we propose an optimal design framework of a rotor. In the framework, objective functions of rigidity and mass are defined, and the relationship between high rigidity and the first-order frequency is discussed. In order to find the optimal values, an accelerated optimization method based on response surface (ARSO) is proposed to find the suitable design parameters of rigidity and mass. Because the higher rigidity can be transformed into the first-order natural frequency by objective function, this paper analyzes the first-order frequency and mass of a motor rotor in the experiment. The results proved that not only is the fractional model effective, but also the ARSO can optimize the rotor structure. The first-order natural frequency of asynchronous motor rotor is increased by 11.2 %, and the mass is reduced by 13.8 %, which can realize high stiffness and light mass of asynchronous motor rotors.

Reliability of Buried Pipeline Using a Theory of Probability of Failure

2006 ◽  
Vol 110 ◽  
pp. 221-230 ◽  
Author(s):  
Ouk Sub Lee ◽  
Dong Hyeok Kim ◽  
Seon Soon Choi
Keyword(s):  
Failure Probability ◽  
Probability Of Failure ◽  
Operating Conditions ◽  
Reliability Estimation ◽  
Design Parameters ◽  
Buried Pipeline ◽  
Safety Level ◽  
First Order ◽  
Reliability Method ◽  
Corrosion Defects

The reliability estimation of buried pipeline with corrosion defects is presented. The reliability of corroded pipeline has been estimated by using a theory of probability of failure. And the reliability has been analyzed in accordance with a target safety level. The probability of failure is calculated using the FORM (first order reliability method). The changes in probability of failure corresponding to three corrosion models and eight failure pressure models are systematically investigated in detail. It is highly suggested that the plant designer should select appropriate operating conditions and design parameters and analyze the reliability of buried pipeline with corrosion defects according to the probability of failure and a required target safety level. The normalized margin is defined and estimated accordingly. Furthermore, the normalized margin is used to predict the failure probability using the fitting lines between failure probability and normalized margin.

scholarly journals MPAS-Albany Land Ice (MALI): A variable resolution ice sheet model for Earth system modeling using Voronoi grids

2018 ◽  
Author(s):  
Matthew J. Hoffman ◽  
Mauro Perego ◽  
Stephen F. Price ◽  
William H. Lipscomb ◽  
Douglas Jacobsen ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Earth System Model ◽  
Coupled Systems ◽  
System Model ◽  
Type Model ◽  
Earth System ◽  
Ice Dynamics ◽  
Variable Resolution ◽  
Horizontal Advection ◽  
First Order

Abstract. We introduce MPAS-Albany Land Ice (MALI), a new, variable resolution land ice model that uses unstructured Voronoi grids on a plane or sphere. MALI is built using the Model for Prediction Across Scales (MPAS) framework for developing variable resolution Earth System Model components and the Albany multi-physics code base for solution of coupled systems of partial-differential equations, which itself makes use of Trilinos solver libraries. MALI includes a three-dimensional, first-order momentum balance solver ("Blatter-Pattyn") by linking to the Albany-LI ice sheet velocity solver, as well as an explicit shallow ice velocity solver. Evolution of ice geometry and tracers is handled through an explicit first-order horizontal advection scheme with vertical remapping. Evolution of ice temperature is treated using operator splitting of vertical diffusion and horizontal advection and can be configured to use either a temperature or enthalpy formulation. MALI includes a mass-conserving subglacial hydrology model that supports distributed and/or channelized drainage and can optionally be coupled to ice dynamics. Options for calving include "eigencalving", which assumes calving rate is proportional to extensional strain rates. MALI is evaluated against commonly used exact solutions and community benchmark experiments and shows the expected accuracy. We report first results for the MISMIP3d benchmark experiments for a Blatter-Pattyn type model and show that results fall in-between those of models using Stokes flow and L1L2 approximations. We use the model to simulate a semi-realistic Antarctic Ice Sheet problem for 1100 years at 20 km resolution. MALI is the glacier component of the Energy Exascale Earth System Model (E3SM) version 1, and we describe current and planned coupling to other components.

A Novel Absorption Regeneration-Thermodynamic Heat Engine Cycle

1978 ◽  
Vol 100 (4) ◽  
pp. 566-570 ◽  
Author(s):  
B. Nimmo ◽  
R. Evans
Keyword(s):  
Electrical Power ◽  
Research Work ◽  
Heat Engine ◽  
Rankine Cycle ◽  
Design Parameters ◽  
Plant Design ◽  
Power Cycle ◽  
First Order ◽  
Important Design ◽  
Heat Engine Cycle

This paper introduces and provides a first order thermal cycle analysis of a new power plant design, the absorption-regeneration power cycle. Preliminary analysis indicates that this new cycle may have potential for increased operating efficiencies compared to the modified Rankine cycle presently in use for most stationary electrical power production. Graphs are presented to illustrate calculated efficiencies as well as some important design parameters of the cycle. Research work on extending presently available thermo-chemical data required to improve the model analysis is suggested.

scholarly journals Reliability Analysis of Flexible Pavement Using First Order Method

2020 ◽  
pp. 38-54
Author(s):  
Sameh S. Abd El- Fattah ◽  
Ahmed E. Abu El- Maaty ◽  
Ibrahim H. Hashim
Keyword(s):  
Design Methodology ◽  
Flexible Pavement ◽  
Pavement Design ◽  
Design Parameters ◽  
Army Corps ◽  
First Order ◽  
Failure Patterns ◽  
Reliability Method ◽  
Current Design ◽  
The Impact

Flexible pavement design is influenced by many design parameters such as (traffic characterization, pavement depths, structure materials and environmental conditions). To study the impact of variations in design parameters on pavement performance, several attempts have been achieved to add reliability concept to the mechanistic-empirical (M-E) design of pavements. In (M-E) design of pavements, the pavement life depends on subgrade rutting and fatigue cracking, considering them as independent failure patterns. The current design methodology used in many countries such as Egypt is ignoring the impact of temperature variation (despite its importance) on the pavement design. This research aimed to predict the pavement reliability due to variation in pavement design parameters especially temperature using the first-order reliability method (FORM) considering rutting and fatigue failures. Moreover, a comparison was performed between regressions models represented from different pavement agencies to recommend the most efficient one for Egyptian temperature. The results obtained that, considering design parameters variations (without temperature); the reliability based on US Army Corps method (91.64%) was the nearest one to the current design methodology in Egypt (91.0%). After adding temperature variations, the reliability was clearly affected where the regression model of Shell Research agency was the most appropriate one for all Egyptian temperature zones as it achieved the lowest error mean (-0.03) and the lowest error standard deviation (0.0011). Moreover, the air temperature of 28ºC was considered as the inflection point for pavement reliability-temperature curve in Egypt.

Reliability-Based Design of Reinforced Earth Retaining Walls

1996 ◽  
Vol 1526 (1) ◽  
pp. 64-78 ◽  
Author(s):  
Imad A. Basheer ◽  
Yacoub M. Najjar
Keyword(s):  
Order Approximation ◽  
Retaining Walls ◽  
Design Parameters ◽  
Physical Parameters ◽  
Statistical Parameters ◽  
First Order ◽  
Reliability Based Design ◽  
Reinforced Earth ◽  
Mean And Variance ◽  
The Mean

Reliability of an earth structure can be assessed from the knowledge of the governing probability distribution and its related statistical parameters, namely, the mean and variance. In this study, the mean and variance for the design parameters (width and length of the reinforcing ties) of reinforced earth retaining walls supporting sandy soils are determined using the first-order Taylor series approximation. Design diagrams that enable estimation of both mean and variance also are developed to avoid extensive computations that involve partial differentiation. Errors associated with truncating second-order terms are also evaluated. It is found that for soils with moderately variable physical parameters, the first-order approximation is adequate for estimating both the mean and variance.

scholarly journals The approximate calculation of the natural frequencies of a Stockbridge type vibration damper and analysis of natural frequencies' sensitivity to the structural parameters

2021 ◽  
Vol 12 (2) ◽  
pp. 863-873
Author(s):  
Qing Yin ◽  
Jianli Zhao ◽  
Yong Liu ◽  
Yisheng Zhang
Keyword(s):  
Sensitivity Analysis ◽  
Approximate Calculation ◽  
Natural Frequencies ◽  
Second Order ◽  
Design Parameters ◽  
Gyration Radius ◽  
Vibration Damper ◽  
First Order ◽  
Highly Sensitive ◽  
Eccentric Distance

Abstract. Vibration damper is widely used in overhead transmission lines to alleviate aeolian vibration. Its natural frequencies are important parameters for a vibration damper. In this paper, the approximate calculation formulas of natural frequencies of the one-side subsystem of a Stockbridge type vibration damper were derived and the design sensitivity analysis of the natural frequencies was studied using partial differential equations with respect to each concerned parameter including the length of the steel strand, the mass of the counterweight, the eccentric distance, and the radius of gyration of the counterweight. Through a case study that considered a variation of up to ±30 % in the values of the design parameters, the exact calculation and approximate calculation results of the natural frequencies were analysed, and the sensitivity of the vibration damper's natural frequencies to the design parameters was studied. The results show that, within the range of the parameters used in this study, the approximately calculated first-order frequency is lower than the exact values, whereas the approximately calculated second-order frequency is larger than the exact values. The sensitivity analysis indicates that the first-order frequency is highly sensitive to the steel strand's length, whereas it is moderately sensitive to the counterweight's mass and slightly sensitive to the eccentric distance and the gyration radius of the counterweight; the second-order frequency is highly sensitive to the steel strand's length and the gyration radius of the counterweight, moderately sensitive to the counterweight's mass, and slightly sensitive to the eccentric distance. It will provide theoretical guidance and approximate analysis method in engineering for the design of the vibration damper.

Effects of aeroelasticity on coning motion of a spinning missile

2016 ◽  
Vol 230 (14) ◽  
pp. 2581-2595 ◽  
Author(s):  
Zhongjiao Shi ◽  
Liangyu Zhao
Keyword(s):  
Theoretical Analysis ◽  
Linear Equation ◽  
Vibration Mode ◽  
Necessary Conditions ◽  
Stable Region ◽  
Design Parameters ◽  
Governing Equations ◽  
First Order ◽  
Sufficient And Necessary Conditions ◽  
The Stability

The coning motion is a basic angular behavior of spinning missiles. Research on the stability of coning motion is always active. In this paper, the integrated nonlinear governing equations of rigid-elastic angular motion for a spinning missile with high fineness ratio are derived firstly following the Lagrangian approach. Secondly, a set of linear equation is obtained under some assumptions considering the first order vibration mode in the form of complex summation for theoretical analysis. Finally, the sufficient and necessary conditions of coning motion dynamic stability for spinning missile with and without an acceleration autopilot are analytically derived and verified by numerical simulations based on the linear equation. It is concluded that the aeroelasticity can shrink the stable region of the design parameters, even lead to a divergent coning motion.

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