scholarly journals Structural Design and Impact Analysis of Deployable Habitat Modules

2018 ◽  
Vol 2018 ◽  
pp. 1-15
Author(s):  
Yihong Hong ◽  
Wenjuan Yao ◽  
Yan Xu
Keyword(s):  
Structural Design ◽  
Impact Analysis ◽  
Dynamic Responses ◽  
Design Parameters ◽  
Composite Shells ◽  
Steel Cylinder ◽  
Low Speed ◽  
Fea Model ◽  
Future Space ◽  
Final Design

Space-deployable habitat modules provide artificial habitable environments for astronauts and will be widely used for the construction of future space stations and lunar habitats. A novel structural design concept of space-deployable habitat modules consisting of flexible composite shells and deployable trusses has been proposed. Geometric relationships of deployable trusses based on two types of scissor elements were formulated. Flexible composite shells of space habitat modules were designed, and a nonlinear FEA model using ANSYS software was described. Considering folding efficiencies, stiffness, and strength of the structures, the influences of design parameters were analyzed and the final design scheme of space-deployable habitat modules was determined. After detailing the structural designs, low-speed impact dynamic responses between the structures and a stainless steel cylinder were simulated. The analysis results show that dynamic responses are only significant at the point of low-speed impact. The works will provide technical supports for structural designs and engineering applications of space-deployable habitat modules.

Vibroacoustic design optimization of curved composite shells

2021 ◽  
Vol 29 (9_suppl) ◽  
pp. S1520-S1531
Author(s):  
Rilwan K Apalowo ◽  
Dimitrios Chronopoulos
Keyword(s):  
Optimal Design ◽  
Structural Design ◽  
Composite Structures ◽  
Sensitivity Analyses ◽  
Computational Time ◽  
Design Parameters ◽  
Sandwich Shell ◽  
Acoustic Transmission ◽  
Composite Shells ◽  
Model Composite

The need to simultaneously optimize the structural design properties, and attain a satisfactory vibroacoustic performance for composite structures, has been a challenging task for modern structural engineers. This work is aimed at developing a statistical energy analysis (SEA) based numerical scheme for computing the optimal design parameters of each individual layer of layered curved shells having arbitrary complexities and layering. The main novelty of the work focuses on the computation of SEA properties for curved composite shells and derive the sensitivities of the acoustic transmission coefficient, expressed through the computed SEA properties, with respect to the structural design characteristics to be optimized. A wave finite element approach is employed to calculate the wave propagation constants of the curved shell. The calculated wave constants are then applied to compute the vibroacoustic properties for the curved shell using a SEA approach. Sensitivity analyses are conducted on the vibroacoustic properties to estimate their response to changes in the structural properties. Gradient vector is then formulated and hence the Hessian matrix, which is employed to formulate a Newton-like optimisation algorithm for optimizing the properties of the layered composite shell. The developed scheme is applied to a sandwich shell; optimal design parameters of [Formula: see text] and [Formula: see text] are obtained for the facesheet and the core of the shell whose base parameters are [Formula: see text] and [Formula: see text], respectively. This simultaneously optimizes the structure with maximum stiffness and minimum mass and attains a satisfactory dynamic performance for acoustic transmission through the sandwich shell. The principal advantage of the scheme is the ability to accurately model composite panels of arbitrary curvature at a rational computational time.

Design Considerations and Validation of Trailing Edge Pressure Side Bleed Cooling

2009 ◽  
Author(s):  
Joerg Krueckels ◽  
Michael Gritsch ◽  
Martin Schnieder
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Thickness Effect ◽  
Design Parameters ◽  
Pressure Side ◽  
Trailing Edge ◽  
Low Speed ◽  
Final Design ◽  
Overhang Length ◽  
Important Design

One important design measure, which allows achieving a higher efficiency in heavy-duty gas turbines, is reducing the trailing edge thickness of the turbine vanes and blades. A common approach to achieve an efficient cooling of thin trailing edges is pressure side coolant ejection. As the trailing edge is one of the areas of the vanes and blades with the highest heat load, a careful design and validation approach is required. First, the most important design parameters were identified for the design of pressure side bleed. In the present investigation, focus is given to the blockage of the internal features, slot width, overhang length, pressure side lip thickness, effect of rotation and blowing rate. Flat plate test results from a low speed rig are used to choose suitable parameters, which fulfill requirements of a specific design. Previous investigations have shown that contrary to CFD using steady RaNS, unsteady detached eddy simulations can predict film effectiveness of pressure side bleed with good accuracy. Therefore, this approach is used to complete experimental data. The effect of going from low speed rig conditions to engine conditions is modeled with this approach. The final design is investigated in a high-speed cascade rig. Film effectiveness is measured using thermocromic liquid crystals. The cascade results confirm results from the low speed rig. High levels of film effectiveness allow effective cooling of the trailing edge overhang.

Collision analysis and safety evaluation using a collision model for the frontal robot–human impact

Robotica ◽  
2014 ◽  
Vol 33 (7) ◽  
pp. 1536-1550 ◽  
Author(s):  
Jung-Jun Park ◽  
Jae-Bok Song ◽  
Sami Haddadin
Keyword(s):  
Impact Analysis ◽  
Safety Evaluation ◽  
Design Parameters ◽  
Body Parts ◽  
Robot Arm ◽  
Collision Model ◽  
Crash Testing ◽  
Mass Spring ◽  
Head Neck ◽  
Significant Attention

SUMMARYThe safety analysis of human–robot collisions has recently drawn significant attention, as robots are increasingly used in human environments. In order to understand the potential injury a robot could cause in case of an impact, such incidents should be evaluated before designing a robot arm based on biomechanical safety criteria. In recent literature, such incidents have been investigated mostly by experimental crash-testing. However, experimental methods are expensive, and the design parameters of the robot arm are difficult to change instantly. In order to solve this issue, we propose a novel robot-human collision model consisting of a 6-degree-of-freedom mass-spring-damper system for impact analysis. Since the proposed robot-human consists of a head, neck, chest, and torso, the relative motion among these body parts can be analyzed. In this study, collision analysis of impacts to the head, neck, and chest at various collision speeds are conducted using the proposed collision model. Then, the degree of injury is estimated by using various biomechanical severity indices. The reliability of the proposed collision model is verified by comparing the obtained simulation results with experimental results from literature. Furthermore, the basic requirements for the design of safer robots are determined.

Electrothermal Characterization of Doped-Si Heated Microcantilevers Under Periodic Heating Operation

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Sina Hamian ◽  
Andrew M. Gauffreau ◽  
Timothy Walsh ◽  
Jungchul Lee ◽  
Keunhan Park
Keyword(s):  
Microelectromechanical Systems ◽  
Transfer Functions ◽  
Design Parameters ◽  
Periodic Heating ◽  
Element Analysis ◽  
Full Spectrum ◽  
Frequency Dependent ◽  
Thermal Transfer ◽  
Fea Model

This paper reports the frequency-dependent electrothermal behaviors of a freestanding doped-silicon heated microcantilever probe operating under periodic (ac) Joule heating. We conducted a frequency-domain finite-element analysis (FEA) and compared the steady periodic solution with 3ω experiment results. The computed thermal transfer function of the cantilever accurately predicts the ac electrothermal behaviors over a full spectrum of operational frequencies, which could not be accomplished with the 1D approximation. In addition, the thermal transfer functions of the cantilever in vacuum and in air were compared, through which the frequency-dependent heat transfer coefficient of the air was quantified. With the developed FEA model, design parameters of the cantilever (i.e., the size and the constriction width of the cantilever heater) and their effects on the ac electrothermal behaviors were carefully investigated. Although this work focused on doped-Si heated microcantilever probes, the developed FEA model can be applied for the ac electrothermal analysis of general microelectromechanical systems.

scholarly journals Development of a Novel Double-Ring Deployable Mesh Antenna

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Yan Xu ◽  
Fuling Guan ◽  
Xian Xu ◽  
Hongjian Wang ◽  
Yao Zheng
Keyword(s):  
Low Frequency ◽  
Design Concept ◽  
Design Parameters ◽  
Accuracy Measurement ◽  
Double Ring ◽  
Reflective Surface ◽  
Final Design ◽  
Geometric Relationship ◽  
Relationship Of ◽  
Adjustment Test

This paper addresses a type of deployable mesh antenna consisting of the double-ring deployable truss edge frame and the cable net reflector. The structural design concept of the deployable antennas is presented. The deployable truss is designed and the geometric relationship of each strut length is formulated. Two types of radial truss elements are described and compared. The joint pattern and the active cables of the final design concept are determined. The pattern of the cable net is the three-orientation grid. Two connection schemes between the reflector and the deployable edge frame are investigated. The design parameters and the shape adjustment mechanism of this cable net are determined. The measurement test technologies of the antennas on the ground including test facilities, deployment test, and measurement and adjustment test are proposed. The antenna patterns are analyzed based on the real surfaces of the reflector obtained by the reflective surface accuracy measurement. The tests and analytic results indicated that the accuracy of the reflective surface is high and is suitable for low-frequency communication.

Load Analysis of Wheel Hub Bearing in Wheel Driving System with Exterior Rotor Motor

2012 ◽  
Vol 479-481 ◽  
pp. 670-675
Author(s):  
Jia Wu ◽  
Lu Xiong
Keyword(s):  
Working Conditions ◽  
Structural Design ◽  
Design Parameters ◽  
Driving System ◽  
Load Analysis

Wheel hub bearings are weak parts in wheel driving system because of its bad condition of loads. This paper has selected two typical extreme working conditions for vehicle, namely braking with turning and driving with turning, and analyzed loads of wheel hub bearings. The design parameters of wheel hub bearings are analyzed separately, with the purpose of finding the key parameters in them, which influenced the force of bearing, and finally these important parameters for structural design have been optimized, the force of wheel hub bearings has been decreased by 45%.

An Approach to Represent Imprecision in Interactive Design Using Fuzzy Set Theory

1992 ◽  
Author(s):  
Numan Iqbal ◽  
Gary L. Kinzel
Keyword(s):  
Set Theory ◽  
Fuzzy Set ◽  
Fuzzy Set Theory ◽  
Ohio State University ◽  
Design Parameters ◽  
State University ◽  
Design Variables ◽  
Final Design ◽  
The Ohio State University ◽  
Number Of Iterations

Abstract Imprecision in the values of design parameters is an inherent character of the analysis stage of engineering design when the ideas have not yet converted to precise values and some of the design parameters remain flexible. The goal of this paper is to illustrate the application of the concepts of fuzzy set theory to represent this imprecision in design after a basic analytical model of the part being evaluated is developed. The idea is to help the designer efficiently study the effect of changing the values of certain parameters so that the number of iterations required to reach a final design can be reduced. The concepts of fuzzy set theory are used to represent design variables and the vertex method is utilized to calculate the fuzzy outputs in an interactive manner through an existing constraint manager (Design Shell) developed at The Ohio State University.

Improvement on Curve Negotiation Performance of Suspended Monorail Vehicle Considering Flexible Guideway

2020 ◽  
Vol 20 (05) ◽  
pp. 2050057
Author(s):  
Qinglie He ◽  
Chengbiao Cai ◽  
Shengyang Zhu ◽  
Kaiyun Wang ◽  
Yongzhi Jiang ◽  
...  
Keyword(s):  
Interaction Model ◽  
Dynamic Responses ◽  
Secondary Development ◽  
Design Parameters ◽  
Lateral Vibration ◽  
Vibration Level ◽  
Radial Stiffness ◽  
Negotiation Performance ◽  
Lateral Displacements ◽  
Curve Negotiation

This work presents the investigation and improvement on curve negotiation performance of suspended monorail vehicle considering a flexible guideway. First, a spatial train–guideway interaction model of suspended monorail system (SMS) is established based on the secondary development of ANSYS software. Then, the dynamic analysis of the train over the flexible curved guideway is conducted, and the curve negotiation performance of the vehicle and the guideway vibration feature are revealed. Subsequently, several crucial design parameters that significantly influence the curve negotiation performance of the vehicle are found, and their influences on the train–guideway dynamic responses are systematically investigated. Finally, by comprehensively considering the dynamic indexes of the vehicle–guideway system, the optimal ranges of these crucial design parameters are obtained. Results show that decreasing the radial stiffness of guiding tyre can effectively reduce the lateral vibration levels of vehicle and guideway, but it would increase the lateral displacements of the bogie and hanging beam; and the radial stiffness is finally suggested to be around 1[Formula: see text]kN/mm by comprehensively considering all dynamic indexes. Increasing the initial compression displacement of guiding tyre can well limit the lateral displacements of the bogie and the hanging beam, thus enhancing the train running safety; however, it would intensify the vehicle-guideway lateral vibration level; especially, the optimal initial compression displacement of guiding tyre is related to its radial stiffness characteristics. To ensure a good curve negotiation performance of vehicle and guideway vibration level, the stiffness of the anti-roll torsion bar and the initial gradient angle of the installed trapezoid four-link suspended device are suggested to be 1.0[Formula: see text]MNm/rad and 65–[Formula: see text], respectively.

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