Elementary Three-Dimensional Interactive Rotor Blade Impact Analysis

1976 ◽  
Vol 98 (4) ◽  
pp. 480-486 ◽  
Author(s):  
R. W. Cornell
Keyword(s):  
Impact Analysis ◽  
Impact Force ◽  
Three Dimensional ◽  
Soft Or ◽  
Mass System ◽  
Centrifugal Stiffening ◽  
Modes Of Vibration ◽  
Fan Blade ◽  
The Impact ◽  
Good Agreement

A theoretical analysis is presented which defines the loading and response of a rotor fan blade due to soft or frangible impacts in terms of the three fundamental modes of vibration by representing the blade as a lumped, spring-mass system. The analysis includes the effects of centrifugal stiffening, blade twist, retention stiffness and orientation, damping, and blade motion and deflection on the impact force. The features, solution, program, and applications of this analysis are reviewed, and the results are compared with those from a number of blade and specimen tests and found to be in good agreement.

Numerical Simulation of Bird Strike Damage on Jet Engine Fan Blade

2004 ◽  
Author(s):  
Kazuo Shimamura ◽  
Tadashi Shibue ◽  
Donald J. Grosch
Keyword(s):  
Numerical Simulation ◽  
Impact Force ◽  
Bird Strike ◽  
Soft Body ◽  
Jet Engine ◽  
Fan Blade ◽  
The Impact ◽  
Interaction Problem ◽  
Numerical Simulation Technique ◽  
Good Agreement

Aircraft jet engine should be designed to keep the required performance against for the event of foreign object ingestion, such as bird-strike. For the purpose to realize highly efficient and more advanced design of fan blade of jet engine, a numerical simulation technique for bird-strike problem has developed. Good agreement was obtained between simulation results and the soft body impact tests described in this paper. It was also shown that bird-strike problem has to be recognized as a fluid-structure interaction problem, because the impacted bird behaves like fluid and the impact force is highly influenced by the deformation of fan blade.

Simplified Method for Predicting Impact Loads of Solid-Walled Transportation Packagings for Radioactive Materials

1989 ◽  
Vol 111 (3) ◽  
pp. 316-321 ◽  
Author(s):  
W. W. Teper ◽  
R. G. Sauve´
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Impact Analysis ◽  
Impact Force ◽  
Impact Loads ◽  
Radioactive Materials ◽  
Element Analysis ◽  
Elastic Plastic ◽  
The Impact ◽  
Good Agreement

Transportation packagings for radioactive materials must withstand severe impact conditions without loss of integrity and without excessive permanent distortions in the seal regions. The compliance with the requirements may be shown either through extensive testing, elastic-plastic impact analysis, or a combination of both. Elastic-plastic finite element analysis, although less costly than testing, is usually expensive and time consuming. In this paper, simplified methods for determining the impact force are presented for the following impact cases of solid-walled casks: impact on a pin, impact on an edge, and impact on a corner. The results of the simplified methods are in good agreement with the results of elastic-plastic finite element analysis. It is shown that in each case almost the entire impact energy is dissipated by the plastic deformation of the material in the impact zone.

Vortex rings impinging on walls: axisymmetric and three-dimensional simulations

1993 ◽  
Vol 256 ◽  
pp. 615-646 ◽  
Author(s):  
Paolo Orlandi ◽  
Roberto Verzicco
Keyword(s):  
Numerical Simulations ◽  
Strain Tensor ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Vortex Rings ◽  
Compression Phase ◽  
Vortex Pairing ◽  
The Impact ◽  
Good Agreement ◽  
Three Dimensional Simulations

Accurate numerical simulations of vortex rings impinging on flat boundaries revealed the same features observed in experiments. The results for the impact with a free-slip wall compared very well with previous numerical simulations that used spectral methods, and were also in qualitative agreement with experiments. The present simulation is mainly devoted to studying the more realistic case of rings interacting with a no-slip wall, experimentally studied by Walker et al. (1987). All the Reynolds numbers studied showed a very good agreement between experiments and simulations, and, at Rev > 1000 the ejection of a new ring from the wall was seen. Axisymmetric simulations demonstrated that vortex pairing is the physical mechanism producing the ejection of the new ring. Three-dimensional simulations were also performed to investigate the effects of azimuthal instabilities. These simulations have confirmed that high-wavenumber instabilities originate in the compression phase of the secondary ring within the primary one. The large instability of the secondary ring has been explained by analysis of the rate-of-strain tensor and vorticity alignment. The differences between passive scalars and the vorticity field have been also investigated.

Hydrodynamic Impact Analysis of a Cylinder

1987 ◽  
Vol 109 (3) ◽  
pp. 237-243 ◽  
Author(s):  
R. Cointe ◽  
J.-L. Armand
Keyword(s):  
Impact Analysis ◽  
Impact Force ◽  
Horizontal Cylinder ◽  
Inviscid Fluid ◽  
Hydrodynamic Impact ◽  
Impact Forces ◽  
Corrective Term ◽  
Simplifying Assumptions ◽  
New Formula ◽  
The Impact

The problem of the vertical entry of a rigid horizontal cylinder into an incompressible inviscid fluid initially at rest is addressed. The contributions of previous researchers are presented and discussed in the light of various assumptions introduced and the validity of the results obtained. Based on this review, realistic simplifying assumptions are introduced and the problem formulated. The method of matched asymptotic expansions is used to solve the resulting boundary-value problem. A new formula for the impact force is obtained, which differs from the classical von Ka´rma´n’s formula by a corrective term. The results obtained are compared with those of experimental observations and numerical calculations. The method may be extended to different geometries and nonvertical velocities to provide an estimate of the impact forces on the partially emerged pontoons of damaged semi-submersibles.

Research of the Installation Angle of New Rotor Impact Plate Based on EDEM

2011 ◽  
Vol 80-81 ◽  
pp. 1133-1137
Author(s):  
De Rong Duan ◽  
Fang Zhao ◽  
Song Wang ◽  
Xian Xin Chen
Keyword(s):  
Dynamic Simulation ◽  
Impact Force ◽  
Three Dimensional ◽  
Substantial Effect ◽  
Maximum Speed ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Installation Angle ◽  
Impact Plate ◽  
The Impact

The three-dimensional model of new rotor was imported into EDEM for dynamic simulation, the maximum speed and force were analysied in the EDEM,indicating that the material along the deterministic trajectory collide with the impact plate for second acceleration after the first acceleration in new rotor, the velocity after second acceleration was 2.3 times than the first acceleration.The impact force and angle did not substantial effect on the second acceleration by comprehensive comparing,the 69m/s speed and less impact force were generated in the new rotor with 2° impact plate installation angle.

Internal Impact Analysis of a Novel Controllable Metamorphic Palletizing Robot Mechanism

2014 ◽  
Vol 551 ◽  
pp. 481-486 ◽  
Author(s):  
Ru Gui Wang ◽  
Hui Qing Chen ◽  
Ye Xun Li ◽  
Qing Ming Zou ◽  
Hua Qiang Yuan
Keyword(s):  
Impact Analysis ◽  
Impact Force ◽  
Kinetic Characteristic ◽  
Stability Study ◽  
Total Momentum ◽  
Impact Time ◽  
Metamorphic Mechanism ◽  
The Impact ◽  
The Relationship

Metamorphic mechanism would result in impact when it was changing from one configuration to the next. As a result, the internal impact force would bring about great vibration for the mechanism. What was more, it would make the mechanism be unstable. Therefore, the internal impact for metamorphic mechanism was expected to be analyzed. The controllable metamorphic palletizing robot mechanism was investigated in this paper. First of all, its kinetic characteristic was analyzed. In addition, the total momentum of the link which suffered impact was calculated. Furthermore, the impact force of the link was known. Finally, the relationship between the impact time when the mechanism was changing configuration and the momentum of the link was described through example study. The work of this paper provides some references for stability study of metamorphic mechanism.

Analytical and Experimental Simulation of Fan Blade Behavior and Damage Under Bird Impact

1991 ◽  
Vol 113 (4) ◽  
pp. 582-594 ◽  
Author(s):  
H. C. Teichman ◽  
R. N. Tadros
Keyword(s):  
Impact Analysis ◽  
Failure Modes ◽  
Three Dimensional ◽  
Structural Response ◽  
Analytical Models ◽  
Experimental Simulation ◽  
Experimental Program ◽  
Contact Algorithm ◽  
Bird Impact ◽  
Fan Blade

An extensive analytical and experimental program has been undertaken to investigate the Foreign Object Damage resistance capabilities of external components for small gas turbofan engines. A transient nonlinear impact analysis has been used to predict the structural response of fan blades under bird ingestion conditions. This analysis is based on finite elements, a three-dimensional bird load model, and an interactive structure-to-bird contact algorithm. Experiments were designed and carried out to record large blade deformations during bird impact, and were used to validate and calibrate the analytical models. The analytical models and testing program are described, and dominant fan blade response and failure modes are presented. Predicted results demonstrate good correlation with tests. Analysis application to fan blade design and other engine components is recommended.

An experimental investigation of the initial force of impact on a sphere striking a liquid surface

1981 ◽  
Vol 108 ◽  
pp. 133-146 ◽  
Author(s):  
M. Moghisi ◽  
P. T. Squire
Keyword(s):  
Experimental Investigation ◽  
Drag Coefficient ◽  
Liquid Surface ◽  
Impact Force ◽  
Theoretical Calculations ◽  
Square Root ◽  
Homogeneous Fluid ◽  
Initial Force ◽  
The Impact ◽  
Good Agreement

Detailed experimental results are presented for the initial impact force on a sphere striking a horizontal liquid surface vertically at speeds in the range 1-3 m s−1. Results are discussed in terms of an impact drag coefficient. Liquids having viscosities in the range 10−3−102 Pa s have been studied. For low viscosities the results have been compared with the theoretical calculations of Shiffman & Spencer. Good agreement has been found in most respects; in particular the impact force varies as the square root of the depth for depths less than a tenth of the radius. The impact drag coefficient has also been studied through the transition from inertia to viscosity-dominated conditions. The variation of the impact drag coefficient is presented as a function of Reynolds number, and its variation in the range 5 × 10−2 < Re < 5 × 103 is shown to resemble that of a fully immersed sphere moving steadily in a homogeneous fluid.

scholarly journals The Influence of an EPS Concrete Buffer Layer Thickness on Debris Dams Impacted by Massive Stones in the Debris Flow

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Xianbin Yu ◽  
Xiaoqing Chen ◽  
Wanyu Zhao ◽  
Jiangang Chen
Keyword(s):  
Debris Flow ◽  
Buffer Layer ◽  
Structural Design ◽  
Impact Force ◽  
Three Dimensional ◽  
Time History ◽  
Expanded Polystyrene ◽  
Debris Dams ◽  
The Impact ◽  
Debris Dam

The failure of debris dams impacted by the massive stones in a debris flow represents a difficult design problem. Reasonable materials selection and structural design can effectively improve the resistance impact performance of debris dams. Based on the cushioning properties of expanded polystyrene (EPS) concrete, EPS concrete as a buffer layer poured on the surface of a rigid debris dam was proposed. A three-dimensional numerical calculation model of an EPS concrete buffer layer/rigid debris dam was established. The single-factor theory revealed change rules for the thickness of the buffer layer concerning the maximal impact force of the rigid debris dam surface through numerical simulation. Moreover, the impact force-time/history curves under different calculation conditions for the rigid debris dam surface were compared. Simulation results showed that the EPS concrete buffer layer can not only effectively extend the impact time of massive stones affecting the debris dam but also reduce the impact force of the rigid debris dam caused by massive stones in the debris flow. The research results provide theoretical guidance for transferring the energy of the massive stone impact, creating a structural design and optimizing debris dams.

scholarly journals Vibration Analysis of a Tire in Ground Contact under Varied Conditions

2017 ◽  
Vol 47 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Murat Karakus ◽  
Aydin Cavus ◽  
Mehmet Colakoglu
Keyword(s):  
Free Vibration ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Concrete Block ◽  
Ground Contact ◽  
Tire Model ◽  
Inflation Pressure ◽  
Monitoring Method ◽  
The Impact ◽  
Good Agreement

Abstract The effect of three different factors, which are inflation pressure, vertical load and coefficient of friction on the natural frequencies of a tire (175/70 R13) has been studied. A three dimensional tire model is constructed, using four different material properties and parts in the tire. Mechanical properties of the composite parts are evaluated. After investigating the free vibration, contact analysis is carried out. A concrete block and the tire are modelled together, using three different coefficients of friction. Experiments are run under certain conditions to check the accuracy of the numerical model. The natural frequencies are measured to describe free vibration and vibration of the tire contacted by ground, using a damping monitoring method. It is seen, that experimental and numerical results are in good agreement. On the other hand, investigating the impact of three different factors together is quite difficult on the natural frequencies. When some of these factors are assumed to be constant and the variables are taken one by one, it is easier to assess the effects.

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