scholarly journals A simulation-based approach to modeling component interactions during design of flapping wing aerial vehicles

2019 ◽  
Vol 11 ◽  
pp. 175682931882232
Author(s):  
John Gerdes ◽  
Hugh A Bruck ◽  
Satyandra K Gupta
Keyword(s):  
Predictive Accuracy ◽  
Voltage Drop ◽  
Flapping Wing ◽  
System Level ◽  
Deformation Model ◽  
Loading Conditions ◽  
Component Level ◽  
Battery Model ◽  
Aerial Vehicle ◽  
Level Performance

A new flapping wing aerial vehicle (FWAV) simulation methodology is presented that combines models of the key subsystems: (1) the actuator, (2) the battery, and (3) the wings. This approach captures component interactions that are inherently coupled in order to realize system-level designs for optimal system performance. The approach demonstrates that coupling between wing sizing, flapping motions, and loading conditions propagate into the motor–battery model to alter system-level performance properties. For the actuator subsystem model, a generalized servo motor using empirically derived coefficients to describe torque and angular velocity bandwidth in terms of voltage and current. This model is coupled with a lithium polymer battery model accounting for the nonlinear voltage drop and capacity derating effects associated with loading conditions. For aerodynamic predictions of the wing subsystem, a blade element model for predicting aerodynamic forces is coupled with an elastic wing deformation model that accounts for bending and twisting of the blade elements. System-level performance is then modeled in a design case study by coupling all of the subsystem models to account for relevant interactions, which generates a design trade space spanning a range of wing sizes, airspeeds, and flapping condition. The results from the simulation offer insight into vehicle configuration settings that provide maximum performance in terms of lift and endurance for the Robo Raven II flapping wing aerial vehicle. Experimental validation of the modeling approach shows good predictive accuracy. In addition, the presented framework offers a generalized approach for coupling interacting subsystems to improve overall predictive accuracy and identify areas where component-level improvements may offer system-level performance gains.

Identifying Critical Connections for the Global Performance of Steel Moment Resisting Frames

2018 ◽  
Vol 763 ◽  
pp. 165-173
Author(s):  
Paul Steneker ◽  
Lydell D.A. Wiebe ◽  
Andre Filiatrault
Keyword(s):  
Local Deformation ◽  
System Level ◽  
Single Type ◽  
Northridge Earthquake ◽  
Component Level ◽  
Moment Resisting Frames ◽  
Global Performance ◽  
Moment Resisting ◽  
Rbs Connections ◽  
Level Performance

The investigations following the unacceptable performance of moment resisting frames (MRFs) in the 1994 Northridge Earthquake led to the development of a variety of alternative ductile connections. Tests have shown that these connections have reliable component-level performance, leading to them being recommended in standards worldwide as pre-qualified for MRFs. Current design practice consists of applying a single type of ductile connection, often the reduced beam section (RBS), uniformly throughout an entire frame. These connections are detailed and inspected to ensure that each connection has a similar minimum deformation capacity throughout the building, regardless of local deformation demands.This paper examines the potential design implications of identifying local areas within a MRF having the greatest joint rotational demands. Once identified, the connections at these locations are deemed critical to the global performance of the frame. First, the collapse analysis of a six-storey MRF with well-detailed RBS connections was conducted to quantify an upper bound system-level performance. Thereafter, a lower bound system-level performance was determined by considering a frame constructed using only connections with a lowered rotational capacity. Subsequent series of analyses were conducted to identify critical locations within the frame where RBS connections must have a high reliable rotational capacity to ensure adequate system-level performance.

Dynamic Infrared System Level Fault Isolation

2003 ◽  
Author(s):  
John A. Naoum ◽  
Johan Rahardjo ◽  
Yitages Taffese ◽  
Marie Chagny ◽  
Jeff Birdsley ◽  
...  
Keyword(s):  
Fault Isolation ◽  
System Level ◽  
System Component ◽  
Component Level ◽  
Ir Imaging ◽  
Non Destructive

Abstract The use of Dynamic Infrared (IR) Imaging is presented as a novel, valuable and non-destructive approach for the analysis and isolation of failures at a system/component level.

Design, aerodynamic analysis and test flight of a bat-inspired tailless flapping wing unmanned aerial vehicle

2021 ◽  
Vol 112 ◽  
pp. 106557
Author(s):  
Dawei Bie ◽  
Daochun Li ◽  
Jinwu Xiang ◽  
Huadong Li ◽  
Zi Kan ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Flapping Wing ◽  
Aerodynamic Analysis ◽  
Aerial Vehicle ◽  
Test Flight

scholarly journals Fully Implicit Stress Update Algorithm for Distortion−Based Anisotropic Hardening with Cross−Loading Effect: Comparative Algorithmic Study and Application to Large−Size Forming Problem

2021 ◽  
Vol 11 (12) ◽  
pp. 5509
Author(s):  
Hongjin Choi ◽  
Seonghwan Choi ◽  
Soo-Chang Kang ◽  
Myoung-Gyu Lee
Keyword(s):  
Predictive Accuracy ◽  
Large Strain ◽  
Implicit Scheme ◽  
Loading Path ◽  
Plastic State ◽  
Loading Conditions ◽  
Integration Algorithm ◽  
Implicit Algorithm ◽  
Fully Implicit ◽  
Large Size

A fully implicit stress integration algorithm is developed for the distortional hardening model, namely the e−HAH model, capable of simulating cross−hardening/softening under orthogonal loading path changes. The implicit algorithm solves a complete set of residuals as nonlinear functions of stress, a microstructure deviator, and plastic state variables of the constitutive model, and provides a consistent tangent modulus. The number of residuals is set to be 20 or 14 for the continuum or shell elements, respectively. Comprehensive comparison programs are presented regarding the predictive accuracy and stability with different numerical algorithms, strain increments, material properties, and loading conditions. The flow stress and r−value evolutions under reverse/cross−loading conditions prove that the algorithm is robust and accurate, even with large strain increments. By contrast, the cutting−plane method and partially implicit Euler backward method, which are characterized by a reduced number of residuals, result in unstable responses under abrupt loading path changes. Finally, the algorithm is implemented into the finite element modeling of large−size, S−rail forming and the springback for two automotive steel sheets, which is often solved by a hybrid dynamic explicit–implicit scheme. The fully implicit algorithm performs well for the whole simulation with the solely static implicit scheme.

scholarly journals QiOi: Performance Isolation for Hyperledger Fabric

2021 ◽  
Vol 11 (9) ◽  
pp. 3870
Author(s):  
Jeongsu Kim ◽  
Kyungwoon Lee ◽  
Gyeongsik Yang ◽  
Kwanhoon Lee ◽  
Jaemin Im ◽  
...  
Keyword(s):  
Data Centers ◽  
Component Level ◽  
Isolation Technique ◽  
Cloud Data ◽  
Cpu Scheduling ◽  
Performance Isolation ◽  
Cloud Data Centers ◽  
A New Technique ◽  
The Impact ◽  
Level Performance

This paper investigates the performance interference of blockchain services that run on cloud data centers. As the data centers offer shared computing resources to multiple services, the blockchain services can experience performance interference due to the co-located services. We explore the impact of the interference on Fabric performance and develop a new technique to offer performance isolation for Hyperledger Fabric, the most popular blockchain platform. First, we analyze the characteristics of the different components in Hyperledger Fabric and show that Fabric components have different impacts on the performance of Fabric. Then, we present QiOi, component-level performance isolation technique for Hyperledger Fabric. The key idea of QiOi is to dynamically control the CPU scheduling of Fabric components to cope with the performance interference. We implement QiOi as a user-level daemon and evaluate how QiOi mitigates the performance interference of Fabric. The evaluation results demonstrate that QiOi mitigates performance degradation of Fabric by 22% and improves Fabric latency by 2.5 times without sacrificing the performance of co-located services. In addition, we show that QiOi can support different ordering services and chaincodes with negligible overhead to Fabric performance.

scholarly journals FLAPPING WING DEVICES FOR MARS EXPLORATION

2011 ◽  
Author(s):  
Asier Ania ◽  
Dominique Poirel ◽  
Marie-Josée Potvin ◽  
Steeve Montminy
Keyword(s):  
Reynolds Number ◽  
Insect Flight ◽  
Low Reynolds Number ◽  
Flapping Wing ◽  
Low Density ◽  
Mars Exploration ◽  
Unsteady Aerodynamic ◽  
Aerial Vehicle ◽  
Low Reynolds

The use of an aerial vehicle would greatly enhance the domain of exploration on Mars. The main constraint in such a design would be the extreme Martian environment. The low-density atmosphere suggests the use of a low Reynolds number flight regime modeled after flapping wing insect flight. This flapping wing flight employs several unsteady aerodynamic mechanisms; delayed stall, wake capture, and rotational mechanisms. Two prototypes, a flapping wing and a rotary-flapping wing hybrid, have been built and will be tested in order to quantify the 'overall lift' generated and allow us to evaluate the efficacy of flapping wing flight on Mars.

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