Development of a High-Fidelity Time-Dependent Aero-Structural Capability for Analysis and Design

2016 ◽  
Author(s):  
Dimitri Mavriplis ◽  
Evan Anderson ◽  
Ray S. Fertig ◽  
Mark Garnich
Keyword(s):  
Time Dependent ◽  
High Fidelity ◽  
Analysis And Design

Nonlinear Vibration Behaviors of Composite Laminated Plates with Time-Dependent Base Excitation and Boundary Conditions

2017 ◽  
Vol 18 (2) ◽  
Author(s):  
Yu-Yang Chai ◽  
Feng-Ming Li ◽  
Zhi-Guang Song
Keyword(s):  
Boundary Conditions ◽  
Theoretical Method ◽  
Laminated Plates ◽  
Time Dependent ◽  
Laminated Plate ◽  
Base Excitation ◽  
Analysis And Design ◽  
Composite Laminated Plate ◽  
Composite Laminated Plates ◽  
Frequency Relationship

AbstractThe nonlinear vibrations of composite laminated plates with time-dependent base excitation and boundary conditions are investigated. According to the von Kármán nonlinear plate theory, the dynamic equations of motion of the laminated plates are established. The nonlinear partial differential equations are transformed to the nonlinear ordinary differential ones using the Bubnov-Galerkin’s  method. The primary resonance and the primary parametric resonance of the laminated plate with time-dependent boundary conditions are investigated by means of the method of multiple scales. The validity of the present theoretical method is verified by comparing the amplitude–frequency relationship curves acquired from the present theoretical method with those calculated from the numerical simulation. The amplitude–frequency characteristic curves and the displacement time histories for different ply angles of the composite laminated plate are analyzed. The effects of the viscous damping factor and the transverse displacement excitation on the amplitude–frequency relationship curves are also studied. The present results are helpful for the nonlinear dynamical analysis and design of the composite laminated plate with time-dependent boundary conditions.

Applications of Polynomial Chaos-Based Cokriging to Simulation-Based Analysis and Design Under Uncertainty

2020 ◽  
Author(s):  
Jethro Nagawkar ◽  
Leifur Leifsson
Keyword(s):  
Robust Design ◽  
Ultrasonic Testing ◽  
Polynomial Chaos ◽  
Robust Design Optimization ◽  
High Fidelity ◽  
Analysis And Design ◽  
Simulation Based ◽  
The Mean ◽  
Design Case ◽  
Global Accuracy

Abstract This paper demonstrates the use of the polynomial chaos-based Cokriging (PC-Cokriging) on various simulation-based problems, namely an analytical borehole function, an ultrasonic testing (UT) case and a robust design optimization of an airfoil case. This metamodel is compared to Kriging, polynomial chaos expansion (PCE), polynomial chaos-based Kriging (PC-Kriging) and Cokriging. The PC-Cokriging model is a multi-variate variant of PC-Kriging and its construction is similar to Cokriging. For the borehole function, the PC-Cokriging requires only three high-fidelity samples to accurately capture the global accuracy of the function. For the UT case, it requires 20 points. Sensitivity analysis is performed for the UT case showing that the F-number has negligible effect on the output response. For the robust design case, a 75 and 31 drag count reduction is reported on the mean and standard deviation of the drag coefficient, respectively, when compared to the baseline shape.

Investigation of a Split-Dimple Fin Geometry for Heat Transfer Augmentation

2008 ◽  
Author(s):  
Mohammad A. Elyyan ◽  
Danesh K. Tafti
Keyword(s):  
Heat Transfer ◽  
Turbulent Flows ◽  
High Heat ◽  
Time Dependent ◽  
High Fidelity ◽  
Heat Conductance ◽  
Flow Acceleration ◽  
Heat Transfer Augmentation ◽  
High Heat Transfer ◽  
Turbulent Statistics

The use of an interrupted plate fin with surface roughness in the form of split-dimples is investigated. Time-dependent high-fidelity simulations are conducted for laminar, early turbulent, and fully turbulent flows, ReH = 360, 800, and 2000. Detailed analysis of the domain’s flow structure, turbulent statistics, and heat transfer distribution is presented. Regions of high heat transfer occur at the fin and protrusion leading edges, at flow impingement on the protrusion faces, and flow acceleration region between protrusions. Flow separation and large wakes induced by the large protruding surfaces of the split-dimples, increase friction losses and reduce heat transfer from the fin. The split-dimple fin has a heat conductance 60–175% higher than that of the plate fin, but at 4–8 times the pressure drop.

Measured and predicted time-dependent stress-strain behaviour of Hong Kong marine deposits

1999 ◽  
Vol 36 (4) ◽  
pp. 760-766 ◽  
Author(s):  
Jian-Hua Yin ◽  
Jun-Gao Zhu
Keyword(s):  
Hong Kong ◽  
Technical Note ◽  
Time Dependent ◽  
Practical Significance ◽  
Stress Strain ◽  
Analysis And Design ◽  
Marine Deposits ◽  
Modelling Framework ◽  
Strain Behaviour ◽  
Dependent Behaviour

Hong Kong marine deposits (HKMD) are considered to be difficult (or weak) soils for civil projects because of low shear strength and time-dependent high compressibility. Understanding and modelling the time-dependent stress-strain behaviour of HKMD are of practical significance in the analysis and design of civil structures on and in HKMD. In this technical note, test data on the time-dependent behaviour of a remoulded HKMD are presented and analysed. An existing elastic viscoplastic (EVP) modelling framework is used to describe the time-dependent stress-strain behaviour of HKMD. The modelling results are compared with the measured results.Key words: stress-strain, time dependent, creep, viscoplastic, triaxial, soil.

A general rollover index for tripped and un-tripped rollovers on flat and sloped roads

2017 ◽  
Vol 233 (2) ◽  
pp. 304-316 ◽  
Author(s):  
Mansour Ataei ◽  
Amir Khajepour ◽  
Soo Jeon
Keyword(s):  
Sensitivity Analysis ◽  
Load Transfer ◽  
Soft Soil ◽  
High Fidelity ◽  
State Variables ◽  
Reliable Index ◽  
Analysis And Design ◽  
Rollover Prevention ◽  
Prevention System ◽  
Rollover Index

In order to develop a rollover prevention system, it is essential to have a reliable index that properly indicates real-time rollover danger during vehicle maneuvers. The existing rollover indices are mainly for un-tripped rollovers and have limitations in detecting tripped rollovers. This study introduces a general rollover index (GRI) for the detection of rollover in both tripped and un-tripped cases and also on flat and sloped roads. Based on the lateral load transfer ratio, the proposed index is analytically derived in terms of measurable vehicle parameters and state variables. The general rollover index considers both lateral and vertical road inputs and thus can indicate tripped rollovers in the instance of curbs, soft soil or bumps. Sensitivity analysis for the proposed index is also provided to evaluate the effects of different vehicle parameters and different state variables on tripped and un-tripped rollovers. The introduced index can be used not only for the development of active rollover prevention systems, but also for rollover analysis and design of vehicles. The performance of the introduced general rollover index is validated through simulations using a high-fidelity CarSim model for a SUV.

scholarly journals Segmental Analysis and Design of Superstructure for Box Girder Balanced Cantilever Bridge by IRC Specification Using Midas Civil

2020 ◽  
pp. 107-114
Author(s):  
L. S. Kalaiselvan
Keyword(s):  
Shear Force ◽  
Bending Moment ◽  
Ground Level ◽  
The Other ◽  
Time Dependent ◽  
Bridge Structure ◽  
Box Girder ◽  
Segmental Analysis ◽  
Analysis And Design ◽  
Creep And Shrinkage

A bridge is a combination of substructure and superstructure that is built over a river, road, or railway to allow people and vehicles to cross from one side to the other. This paper describes about the analysis and design of box girder balanced cantilever bridge using MIDAS CIVIL by IRC loadings, characterized by central span of 130m with two symmetrical sides of 85m.Bridge deck is supported by two piers of 40m height from ground level. The bridge structure has been modelled using MIDAS CIVIL and analysis has been performed to get various output such as bending moment, shear force and time dependent properties such as creep and shrinkage at various points of the bridge. The PSC (prestressed) design of superstructure is performed as per IRC standards to get the output parameters such as principle stresses at construction stage, principle stress for prestressing tendon. While by using balanced cantilever bridge less form work has been required for this type of bridge.

Design of buried structures in squeezing rock in Toronto, Canada

1987 ◽  
Vol 24 (2) ◽  
pp. 232-241 ◽  
Author(s):  
K. Y. Lo ◽  
B. H. Cooke ◽  
D. D. Dunbar
Keyword(s):  
Laboratory Testing ◽  
Site Investigation ◽  
Horizontal Stress ◽  
Time Dependent ◽  
Buried Structures ◽  
Analysis And Design ◽  
Pumping Station ◽  
Time Interaction ◽  
Rock Structure ◽  
Squeezing Rock

The construction of the Domed Stadium in Toronto necessitated the relocation of the John Street Pumping Station and associated water supply tunnels for the downtown Toronto area. The proposed structures include tunnels, shafts, and a new pumping station built in or founded on rock. The shale rock of the Georgian Bay formation is known to possess high horizontal stresses and time-dependent deformation and at this site contains numerous horizontal fractures filled with clay seams. This paper presents the results of the site investigation, field and laboratory testing, analysis, and design for the buried structures. Special provisions for "rock squeeze" for different structures are also described. Key words: tunnels, shafts, shale, squeezing rock, horizontal stress, rock–structure–time interaction.

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