Design Requirements to Reduce Discomfort in Window Viewing: Study on Increasing Degrees of Freedom of Car-Body Shape

2016 ◽  
pp. 651-662
Author(s):  
Kazuki Fujita ◽  
Miwa Nakanishi
Keyword(s):  
Degrees Of Freedom ◽  
Body Shape ◽  
Car Body ◽  
Design Requirements

Hunting Stability Analysis of a New High-Speed Railway Vehicle Model Moving on Curved Tracks

2007 ◽  
Author(s):  
Yung-Chang Cheng ◽  
Sen-Yung Lee
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Lateral Displacement ◽  
Creep Model ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Car Body ◽  
Suspension Parameters ◽  
Virtual Boundary ◽  
Hunting Stability

A new dynamic model of railway vehicle moving on curved tracks is proposed. In this new model, the motion of the car body is considered and the motion of the tuck frame is not restricted by a virtual boundary. Based on the heuristic nonlinear creep model, the nonlinear coupled differential equations of the motion of a fourteen degrees of freedom car system, considering the lateral displacement and the yaw angle of the each wheelset, the truck frame and the car body, moving on curved tracks are derived in completeness. To illustrate the accuracy of the analysis, the limiting cases are examined. In addition, the influences of the suspension parameters on the critical hunting speeds evaluated via the linear and the nonlinear creep models respectively are studied. Furthermore, the influences of the suspension parameters on the critical hunting speeds evaluated via the fourteen degrees of freedom car system and the six degrees of freedom truck system, which the motion of the tuck frame is restricted by a virtual boundary, are compared.

Modal and Forced Response Analysis of Vehicle Systems With Latent Vibration Modes Due to Hydraulic Mounts

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Hyeon Gyu Sakong ◽  
Gyunchul Hur ◽  
Kwang-Joon Kim ◽  
Wonju Jeon
Keyword(s):  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Time Domain Analysis ◽  
Hydraulic Modeling ◽  
Internal Variable ◽  
Forced Response ◽  
Response Analysis ◽  
Car Body ◽  
Modeling Approaches ◽  
Mechanical Mass

Abstract Hydraulic mounts used in vehicles for better isolation of vibrations were often approximated by lumped or mechanical mass-damper-spring (m-c-k) models, although deficiency in such modeling was pointed out and “hydraulic” modeling was proposed as an alternative. In this paper, a brief review on the mechanical m-c-k modeling and “hydraulic” modeling of the hydraulic mounts is presented. A simplest system consisting of a single mass and a hydraulic mount is used to illustrate both equivalence and difference in a closed form between the two modeling approaches. Then, modal analyses are done on an apparently three degrees-of-freedom (DOF) quarter car with a hydraulic mount, where the key idea is to use an internal variable for the movement of fluid mass which is responsible for a “latent” vibration mode. Equations of motion for the apparently 3DOF system, 4DOF system in fact, by the two modeling are formulated. Modal parameters by the proposed “hydraulic” modeling of the hydraulic mount are compared with those by the m-c-k modeling. Forced responses to transient base excitations are also compared between the two modeling approaches to illustrate how much errors can arise in the frequency and time domain analysis. To be more realistic, the modal and forced response analysis on a full car of an apparently 10DOF (3DOF for powertrain, 3DOF for car body, and 4DOF for knuckles and tires) with two more DOF internally for two hydraulic mounts between the powertrain and car body is presented.

The Mechanical System Structure Design and Kinematics Analysis of the Bipedal Humanoid Robot Leg

2014 ◽  
Vol 496-500 ◽  
pp. 857-860
Author(s):  
Deng Qi Cui ◽  
Hong Bing Xin ◽  
Long Liu ◽  
Tan Wang ◽  
Yue Fei Xin
Keyword(s):  
Degrees Of Freedom ◽  
Humanoid Robot ◽  
Screw Theory ◽  
Structure Design ◽  
System Structure ◽  
Joint Movement ◽  
Kinematics Analysis ◽  
Walking Robot ◽  
Design Requirements ◽  
The Mathematical Model

In the study of humanoid robot, the system design and analysis of the legs is the foundation of realizing humanoid walking robot. In this paper, structure design of each leg joint has been introduced, and according to the degrees of freedom of each joint distribution, using screw theory and exponential product formula to establish the mathematical model of the legs, to analyze the kinematics of the legs, finally obtains that the range of joint movement comply with the design requirements.

scholarly journals Body Shape Selection of "Bono Kampar" For Urban Concept Student Car Formula to Fulfill Indonesian Energy-Saving Standards (“KMHE”) with Aerodynamic Analysis

CFD letters ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 104-114
Author(s):  
Nazaruddin ◽  
Syafri ◽  
Yudi Saputra
Keyword(s):  
Drag Coefficient ◽  
Computational Fluid Dynamic ◽  
Body Shape ◽  
Energy Use ◽  
Energy Savings ◽  
Fluid Dynamic ◽  
Flow Simulation ◽  
The Body ◽  
Car Body ◽  
Selection Of

The body shape of a vehicle and the structure need to be considered when designing a vehicle. In addition, the shape of the body tends to significantly affect the vehicle's energy use to counter aerodynamic forces due to wind loads. Therefore, this research aims to determine the body length, width, height, wheel base and ground clearance of vehicles in the selection of Bono Kampar for Urban Concept Car Formula to Fulfill Indonesia Energy-Savings Standards (“KMHE”) with Aerodynamics Analysis. The methods used to create four models of vehicle bodies are dynamic simulation on Computational Fluid Dynamic software are coefficient drag, lift and bland force. The result showed that the car body design needs to have the smallest drag coefficient. This is because when vehicles have a large drag coefficient value, it tends to greatly influence its efficiency or performance. Furthermore, this is useful for minimizing fuel usage, and in allowing the vehicle to reduce the friction force caused by air while driving. The Computational Fluid Dynamic (CFD) software is used to obtain drag coefficients, which is used in Solid works Flow Simulation. From aerodynamic simulation results on four alternative car bodies carried out in this study, the smallest Cd (Coefficient Drag) is the second car body model, which has Drag Coefficient (Cd) of 0.21 Pa.

A Simplified Description Method for Color Appearance Depending on the Car Body Shape

2020 ◽  
Vol 93 (5) ◽  
pp. 144-148
Author(s):  
Ikumi ONO ◽  
Haruyuki GONTANI ◽  
Tsukasa FUJIEDA ◽  
Yutaka MASUDA
Keyword(s):  
Body Shape ◽  
Color Appearance ◽  
Car Body

Random Dynamic Fatigue Analysis of Body Structures of Coach

2011 ◽  
Vol 97-98 ◽  
pp. 765-770
Author(s):  
Zhen Qin ◽  
Wen Tao Xu
Keyword(s):  
Random Vibration ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Accurate Method ◽  
Vibration Characteristic ◽  
Body Structure ◽  
Structure Strength ◽  
Design Requirements ◽  
Pseudo Excitation ◽  
The Finite Element Model

In this paper, an efficacious and accurate method for analyzing random vibration and fatigue lifespan of coaches with high degrees of freedom is developed. Based on the design requirements for structure strength and fatigue lifespan of a coach, the finite element model of its body structure was used to investigate the dynamic behavior of the coach running on a randomly uneven road. The vibration characteristic was derived using the pseudo excitation method (PEM). The fatigue lifespan is discussed by means of the Miner rule, and the fatigue resistance is also studied. The reliability of the proposed method is numerically verified.

An approach to analyze the position and orientation between two parts assembled by non-ideal planes

2020 ◽  
Vol 235 (1-2) ◽  
pp. 41-53
Author(s):  
Jian Zhang ◽  
Lihong Qiao ◽  
Zhicheng Huang ◽  
Nabil Anwer
Keyword(s):  
Performance Analysis ◽  
Degrees Of Freedom ◽  
Product Performance ◽  
Design Stage ◽  
Manufacturing Errors ◽  
Surface Deviations ◽  
Design Requirements ◽  
Position And Orientation ◽  
General Product

Performance analysis, which plays a key role in the design stage, is employed to estimate whether product performance can satisfy design requirements. In general, product performance is gained after parts are assembled; product performance is influenced by the position and orientation deviations (PODs) that occur in directions of the constrained degrees of freedom (DOFs) due to the surface deviations of mating-surfaces. Furthermore, PODs are uncertain because the surface deviations as well as positions in the unconstrained DOF directions can vary randomly. Thus, predicting the consequences of uncertain PODs on product performance is key for performance analysis. Considering that planes are extensively used in assemblies, this study aims to propose a statistical approach to analyze the uncertain PODs of non-ideal planes. A modeling method from the perspective of manufacturing errors is employed to describe the uncertain surface deviations. A method for computing the uncertain PODs based on the progressive adjustment of coordinate systems is proposed. The maximum PODs that characterize the most unfavorable assembly situation are determined as evaluation indicators. Finally, the effectiveness of the presented approach is verified by a case study. Because both the effects of uncertain surface deviations and uncertain positions on PODs can be considered, the approach is expected to help predict the practical effects of uncertain PODs on product performance accurately during the design stage.

scholarly journals Designing hybrid flexure systems and elements using Freedom and Constraint Topologies

2013 ◽  
Vol 4 (2) ◽  
pp. 319-331 ◽  
Author(s):  
J. B. Hopkins
Keyword(s):  
Hybrid Systems ◽  
Case Studies ◽  
Degrees Of Freedom ◽  
Rigid Bodies ◽  
Geometric Shapes ◽  
Design Requirements ◽  
Constraint Topologies ◽  
Exact Constraint ◽  
Synthesis Approach

Abstract. In this paper we introduce the principles necessary to synthesize hybrid flexure systems and elements. Flexure systems consist of rigid bodies that are joined together by flexure elements that elastically deform to guide the system's rigid bodies with desired degrees of freedom (DOFs). The principles introduced here for synthesizing hybrid flexure systems and elements are extensions of the Freedom and Constraint Topologies (FACT) synthesis approach. FACT utilizes a comprehensive library of geometric shapes from which designers can rapidly consider and compare a multiplicity of flexure concepts that achieve any desired set of DOFs. Prior to this paper, designers primarily used these shapes to synthesize parallel and serial flexure systems and elements. With this paper, designers may now use these same shapes to synthesize more general flexures that consist of various combinations of parallel and serial systems and elements (i.e., hybrid configurations). As such, designers can access a larger body of flexure solutions that satisfy demanding design requirements. Instructions for helping designers utilize or avoid the advantages and challenges of over-, under-, and exact-constraint are also provided. Hybrid systems and elements are analysed and designed as case studies.

scholarly journals ANALISIS NUMERIK PENGARUH KECEPATAN TERHADAP SEAKEEPING KAPAL PATROLI PADA DAERAH PELAYARAN SEASTATE 7

2021 ◽  
Vol 4 ◽  
pp. 13-17
Author(s):  
Mohammad Taufik Ar Rozi ◽  
Betty Ariani ◽  
Dedy Wahyudi
Keyword(s):  
Water Surface ◽  
Degrees Of Freedom ◽  
Body Shape ◽  
Critical Value ◽  
Vertical Movement ◽  
Sea Waves ◽  
Six Degrees Of Freedom ◽  
A Value ◽  
Wave Angle ◽  
Standard Limit

Patrol boat is designed not to be slow in its movement on the water surface. To be able to move quickly and agilely, the most important requirement for this type of ship is in its maneuverability. The ship's motion at sea (seakeeping) is influenced by several things, speed, body shape, and the direction of the ship's heading waves. In this study, we analyze the six degrees of freedom, especially on the response of the ship's vertical movement, namely rolling on the sea waves of Seastate 7, especially in extreme weather in the South China Sea. The standard limit used is NORDFORSK 1987 with Light Manual Work Criteria. By entering parameters such as variations in speed and wave angle, such as 0°, 45°, 180° and 270°, then from the graph it can be seen the critical value for each movement. The calculation is carried out with the help of computational software Maxsurf Motions Advanced 20 V8i. The results of this study are the maximum roll movement value that occurs at a speed of 14 knots with a wave angle of 45° with a roll angle value of 6.40o. Furthermore, there is a decrease in the value of the movement along with the increase in the speed of the ship. The minimum roll value occurs when the wave angle is 270° when the ship's speed is 28 knots with a value of 5.69o.

Novel Flexible Pivot With Large Angular Range and Small Center Shift to be Integrated Into a Bio-Inspired Robotic Hand

2010 ◽  
Author(s):  
Javier Martin ◽  
Mathieu Robert
Keyword(s):  
Degrees Of Freedom ◽  
Robotic Hand ◽  
Angular Range ◽  
Center Shift ◽  
Pure Rotation ◽  
Real Behavior ◽  
Rotational Degrees Of Freedom ◽  
Design Requirements ◽  
Robotic Application ◽  
Accurate Matching

This paper presents a novel flexible pivot with large angular range and small center shift. It is conceived to provide the inter-phalangeal rotational degrees of freedom of the fingers of a new bio-inspired robotic hand, simultaneously removing friction and backlash from the mechanism. The specifically developed mathematical model shows that the proposed solution meets all design requirements. Preliminary tests carried out on a prototype show an accurate matching between the model and the real behavior. The advantages offered by the new flexible pivot can be extended to any robotic application where frictionless, zero-backlash, compact and easy to manufacture pivots are required for pure rotation over long angular strokes.

Sign in / Sign up

Export Citation Format

Share Document