scholarly journals Energy Flow in Multibody Limb Models: A Case Study in Frogs

2019 ◽  
Vol 59 (6) ◽  
pp. 1559-1572 ◽  
Author(s):  
Christopher T Richards
Keyword(s):  
Energy Flow ◽  
Center Of Mass ◽  
Coupling Mechanism ◽  
Dynamic Coupling ◽  
Coordinated Motion ◽  
Computational Framework ◽  
Inertia Properties ◽  
Jump Trajectory ◽  
Multi Body

Abstract A frog jump is both simple and difficult to comprehend. The center-of-mass (COM) follows a two-dimensional (2D) path; it accelerates diagonally upward, then traces a predictable arc in flight. Despite this simplicity, the leg segments trace intricate trajectories to drive the COM both upwards and forwards. Because the frog sits crouched with sprawled legs, segments must pivot, tilt, and twist; they solve a long-recognized problem of converting non-linear 3D motion of the leg segments to linear 2D motion of the COM. I use mathematical approaches borrowed from robotics to address: How do frogs manipulate the flow of kinetic energy through their body to influence jump trajectory? I address (1) transfer of motion through kinematic transmission and (2) transfer of motion through dynamic coupling of segment mass-inertia properties. Using a multi-body simulation, I explore how segment acceleration induces rotations at neighboring segments (even without accounting for bi-articular muscles). During jumps, this inertial coupling mechanism is likely crucial for modulating the direction of travel. The frog case study highlights a useful computational framework for studying how limb joints produce coordinated motion.

Multi-body dynamic coupling mechanism for generating throwing arm velocity during baseball pitching

2017 ◽  
Vol 54 ◽  
pp. 363-376 ◽  
Author(s):  
Kozo Naito ◽  
Tokio Takagi ◽  
Hideaki Kubota ◽  
Takeo Maruyama
Keyword(s):  
Coupling Mechanism ◽  
Dynamic Coupling ◽  
Multi Body ◽  
Body Dynamic

On the Application of the Lu-Gre Model to Simulate Joint Friction in Multi-Body Systems

2011 ◽  
Author(s):  
Kedar Gajanan Kale ◽  
Rajiv Rampalli
Keyword(s):  
Friction Model ◽  
Lugre Model ◽  
Friction Forces ◽  
Joint Friction ◽  
Modeling Techniques ◽  
Static Regime ◽  
Increasing Demand ◽  
Automotive Suspension ◽  
Multi Body

Advances in the application of multi-body simulation technology to real world problems have led to an ever increasing demand for higher fidelity modeling techniques. Of these, accurate modeling of friction is of strategic interest in applications such as control system design, automotive suspension analysis, robotics etc. Joints (sometimes referred to as constraints) play an important role in defining the dynamics of a multi-body system. Hence, it is imperative to accurately account for friction forces arising at these joints due to the underlying interface dynamics. In this paper, we discuss the application of LuGre, a dynamic friction model to simulate joint friction. We choose the LuGre model due to its ability to capture important effects such as the Stribeck effect and the Dahl effect. The native 1-d LuGre model is extended to formulate friction computations for non-trivial joint geometries and dynamics in 2 and 3 dimensions. It is also extended to work in the quasi-static regime. Specific applications to revolute, cylindrical and spherical joints in multi-body systems are discussed. Finally, an engineering case study on the effects of joint friction in automotive suspension analysis is presented.

Revisiting Tourism Destination Image: A Holistic Measurement Framework Using Big Data

2021 ◽  
pp. 004728752110247
Author(s):  
Vinh Bui ◽  
Ali Reza Alaei ◽  
Huy Quan Vu ◽  
Gang Li ◽  
Rob Law
Keyword(s):  
Large Scale ◽  
Structural Model ◽  
Destination Image ◽  
Tourism Destination ◽  
Computational Framework ◽  
Four Dimensions ◽  
Tourism Management ◽  
Measurement Framework ◽  
Compare And Contrast

Understanding and being able to measure, analyze, compare, and contrast the image of a tourism destination, also known as tourism destination image (TDI), is critical in tourism management and destination marketing. Although various methodologies have been developed, a consistent, reliable, and scalable method for measuring TDI is still unavailable. This study aims to address the challenge by proposing a framework for a holistic measure of TDI in four dimensions, including popularity, sentiment, time, and location. A structural model for TDI measurement that covers various aspects of a tourism destination is developed. TDI is then measured by a comprehensive computational framework that can analyze complex textual and visual data on a large scale. A case study using more than 30,000 images, and 10,000 comments in relation to three tourism destinations in Australia demonstrates the effectiveness of the proposed framework.

Structural-Acoustic Design at High Frequency Using the Energy Finite Element Method

1995 ◽  
Author(s):  
Robert J. Bernhard ◽  
John E. Huff
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Frequency ◽  
Energy Flow ◽  
Flow Analysis ◽  
Element Formulation ◽  
Joint Models ◽  
Energy Flow Analysis ◽  
Element Method

Abstract Energy flow analysis methods, particularly as implemented using the finite element method, are useful as design techniques for high frequency structural-acoustic applications. In this paper, the derivation of energy flow analysis techniques are summarized. Particular attention is given to the specification of joint models for situations where there is a discontinuity in either geometric properties or material properties. The finite element formulation of this approach is also summarized. A case study is included to illustrate the utility of the method as a design technique.

scholarly journals Investigation of Sloshing Effects on Flexible Aircraft Stability and Response

2020 ◽  
Vol 99 (4) ◽  
pp. 297-308
Author(s):  
Marco Pizzoli
Keyword(s):  
Center Of Mass ◽  
Unsteady Aerodynamics ◽  
Rigid Body Dynamics ◽  
Elastic Behavior ◽  
Lattice Method ◽  
Flexible Aircraft ◽  
Rational Function Approximation ◽  
Sloshing Dynamics ◽  
Mechanical Models

AbstractThe present paper provides an investigation of the effects of linear slosh dynamics on aeroelastic stability and response of flying wing configuration. The proposal of this work is to use reduced order model based on the theory of the equivalent mechanical models for the description of the sloshing dynamics. This model is then introduced into an integrated modeling that accounts for both rigid and elastic behavior of flexible aircraft. The formulation also provides for fully unsteady aerodynamics modeled in the frequency domain via doublet lattice method and recast in time-domain state-space form by means of a rational function approximation. The case study consists of the so-called body freedom flutter research model equipped with a single tank, partially filled with water, located underneath the center of mass of the aircraft. The results spotlight that neglecting such sloshing effects considering the liquid as a frozen mass may overshadow possible instabilities, especially for mainly rigid-body dynamics.

Energy Balance of Indian Villages: A Case Study of Seven Villages

2018 ◽  
Vol 1 (1) ◽  
pp. 77-103
Author(s):  
Amit Garg ◽  
Jaypalsinh Chauhan ◽  
Abha Chhabra ◽  
Tirthankar Nag
Keyword(s):  
Energy Balance ◽  
Energy Flow ◽  
Flow Model ◽  
Crop Yields ◽  
Gujarat State ◽  
Forest Density ◽  
Residential Sector ◽  
Energy Flows ◽  
Stock Change

This paper estimates the rural energy balance of 7 Indian villages of different agro-climate zones. This was done through primary survey of households in each village covering energy consumption, production, export, import and stock change across Crop, Livestock, Industry/Trade, Tree outside forest/plantations and Residential Sector. An energy flow model was created to capture all the various energy flows at household levels. Two villages are showing Negative annual energy balance—one is the desert village of Gujarat state and another is a tribal village of Mizoram state. All other villages were found to be energy positive mainly due to high forest density and high crop yields.

Environmental Impact of an Industrial Kitchen: A Case Study

2017 ◽  
Author(s):  
T. Dai ◽  
A. S. Fleischer ◽  
A. P. Wemhoff ◽  
R. Lee
Keyword(s):  
Environmental Impact ◽  
Cold Storage ◽  
Environmental Performance ◽  
Energy Flow ◽  
Pollution Prevention ◽  
Food Labels ◽  
Standard Data ◽  
Environmental Impact Categories ◽  
Tomato Soup

The large number of industrial kitchens and their energy-intense characteristics provides opportunities for pollution prevention. Life cycle assessment (LCA) is a proper tool not only for unitizing the environmental impact of the complex system of an industrial kitchen, but also for making environmental food labels for the foods produced in the same industrial kitchen. In this study, a gate-to-gate LCA of 11 types of food was conducted to evaluate the environmental impact of a typical industrial kitchen, Villanova University’s Donahue Hall. First, material and energy flow data, including cold storage, food preparation, food display, lighting, heating, ventilation, and air conditioning (HVAC), and dish washing were collected. This data, along with standard data on energy generation and transmission, were used in the LCA. The results show that global warming, fossil fuel depletion and ecotoxicity are the main environmental impact categories. Furthermore, HVAC, cold storage and cooking are the three largest contributors of environmental burden. Using the metrics developed, tuna salad, tomato soup and pasta are the most environmental friendly foods of the 11 sampled food types, while pizza and cheese quesadillas have the worst environmental performance. Energy saving measures for HVAC, cold storage and cooking are proposed.

Linear free energy relationships for transition metal chemistry: case study of CH activation with copper–oxygen complexes

2020 ◽  
Vol 22 (14) ◽  
pp. 7155-7159 ◽  
Author(s):  
Zhenzhuo Lan ◽  
Shaama Mallikarjun Sharada
Keyword(s):  
Free Energy ◽  
Transition Metal ◽  
Transition Metal Complexes ◽  
Linear Free Energy Relationships ◽  
Computational Framework ◽  
Ch Activation ◽  
Linear Free Energy ◽  
Energy Relationships ◽  
Oxygen Complexes

We propose a computational framework for developing Taft-like linear free energy relationships to characterize steric effects on the catalytic activity of transition metal complexes.

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