scholarly journals Dynamic characteristics of mistuned bladed disk system under rub-impact force

2020 ◽  
Vol 12 (11) ◽  
pp. 168781402097306
Author(s):  
Hui Zhang ◽  
Tianyu Zhao ◽  
Hongyuan Zhang ◽  
Honggang Pan ◽  
Huiqun Yuan
Keyword(s):  
Finite Element ◽  
Variable Thickness ◽  
Impact Force ◽  
Element Model ◽  
Force Model ◽  
Disk System ◽  
Element Analysis ◽  
Bladed Disk ◽  
Blade Tip ◽  
The Impact

In order to study the rubbing of the mistuned bladed disk system with variable thickness blades, an elastically supported shaft-variable thickness blades coupled finite element model is established in this paper. A new rubbing force model is proposed considering the variable thickness section characteristics and rotation effect of the variable thickness blade. A method of mistuned parameter identification is introduced which consists of static frequency testing of blades, dichotomy, and finite element analysis. Based on the finite element method, the mistuned bladed disk system is made dynamic analysis in full rubbing by applying the judgment load method. The dynamic response of the mistuned bladed disk system is discussed under different conditions. The results show that increasing the amount of mistuning will increase the system vibration. At high speeds, the impact force will be partially offset by centrifugal force. And the rubbing gap affects the form of rubbing. With the gap decreases, the system will change from intermittent rubbing to continuous rubbing. In addition, when the system is rubbed, due to energy dissipation and blade damping, the stress is transferred from the blade tip to the blade root and attenuated. In general, rubbing is a random complex nonlinear vibration process.

A Reduced Order Approach for the Vibration of Mistuned Bladed Disk Assemblies

1997 ◽  
Vol 119 (1) ◽  
pp. 161-167 ◽  
Author(s):  
M.-T. Yang ◽  
J. H. Griffin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Reduced Order Model ◽  
Order Model ◽  
Disk System ◽  
Element Analysis ◽  
Reduced Order ◽  
Bladed Disk

A reduced order approach is introduced in this paper that can be used to predict the steady-state response of mistuned bladed disks. This approach takes results directly from a finite element analysis of a tuned system and, based on the assumption of rigid blade base motion, constructs a computationally efficient mistuned model with a reduced number of degrees of freedom. Based on a comparison of results predicted by different approaches, it is concluded that: The reduced order model displays structural fidelity comparable to that of a finite element model of the entire bladed disk system with significantly improved computational efficiency; and under certain circumstances both the finite element model and the reduced order model predict quite different response from simple spring-mass models.

scholarly journals A Reduced Order Approach for the Vibration of Mistuned Bladed Disk Assemblies

1995 ◽  
Author(s):  
M.-T. Yang ◽  
J. H. Griffin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Reduced Order Model ◽  
Order Model ◽  
Disk System ◽  
Element Analysis ◽  
Reduced Order ◽  
Bladed Disk

A reduced order approach is introduced in this paper that can be used to predict the steady-state response of mistuned bladed disks. This approach takes results directly from a finite element analysis of a tuned system and, based on the assumption of rigid blade base motion, constructs a computationally efficient mistuned model with a reduced number of degrees of freedom. Based on a comparison of results predicted by different approaches it is concluded that: the reduced order model displays structural fidelity comparable to that of a finite element model of the entire bladed disk system with significantly improved computational efficiency; and under certain circumstances both the finite element model and the reduced order model predict quite different response from simple spring-mass models.

scholarly journals Study on the Impact Resistance of Metal Flexible Net to Rock fall

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Gaosheng Wang ◽  
Yunhou Sun ◽  
Ao Zhang ◽  
Lei Zheng ◽  
Yuzheng Lv ◽  
...  
Keyword(s):  
Finite Element ◽  
Impact Force ◽  
Impact Resistance ◽  
Time History ◽  
Rock Fall ◽  
Fe Model ◽  
Element Analysis ◽  
Inclination Angles ◽  
Fall Protection ◽  
The Impact

Based on experiments and finite element analysis, the impact resistance of metal flexible net was studied, which can provide reference for the application of metal flexible net in rock fall protection. The oblique (30 degrees) impact experiment of metal flexible net was carried out, the corresponding finite element (FE) to the experiment was established, and the FE model was verified by simulation results to the experimental tests from three aspects: the deformation characteristics of metal flexible net, the time history curves of impact force on supporting ropes, and the maximum instantaneous impact force on supporting ropes. The FE models of metal flexible nets with inclination angles of 0, 15, 30, 45, 60, and 75 degrees were established, and the impact resistance of metal flexible nets with different inclination angles was analyzed. The research shows that the metal flexible net with proper inclination can bounce the impact rock fall out of the safe area and prevent rock fall falling on the metal flexible net, thus realizing the self-cleaning function. When the inclination angle of the metal flexible net is 15, 30, and 45 degrees, respectively, the bounce effect after impact is better, the remaining height is improved, the protection width is improved obviously, and the impact force is reduced. Herein, the impact force of rock fall decreases most obviously at 45 degrees inclination, and the protective performance is relatively good.

Finite Element Analysis of a Single-Layer Reticulated Dome under Impact Loading

2010 ◽  
Vol 163-167 ◽  
pp. 327-331 ◽  
Author(s):  
Liang Zheng ◽  
Zhi Hua Chen
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Impact Force ◽  
Impact Load ◽  
Residual Deformation ◽  
Time History ◽  
Single Layer ◽  
Element Analysis ◽  
Deformation Stage ◽  
The Impact

Finite element model of both the single-layer Schwedler reticulated dome with the span of 50m and a Cuboid impactor were developed, incorporating ANSYS/LS-DYNA. PLASTIC_KINEMATIC (MAT_003) material model which takes stain rate into account was used to simulate steel under impact load. The automatic point to surface contact (NODES TO SURFACE) was applied between the dome and impact block. Three stages of time history curve of the impact force on the apex of the single-layer Scheduler reticulated dome including the impact stage, stable stalemate stage, the decaying stage were generalized according to its dynamic response. It must be pointed out that the peak of the impact force of the single-layer reticulated dome increase with the increase of the weight and the velocity of the impact block, but the change of the velocity of the impact block is more sensitive than the change of weight of the impact block for the effect of the peak of the impact force, and a platform value of the impact force of the single-layer reticulated dome change near a certain value, and the duration time of the impact gradually increase. Then four stages of time history curve of the impact displacement were proposed according to the dynamic response of impact on the apex of the single-layer reticulated dome based on numerical analysis. Four stages include in elastic deformation stage, plastic deformation stage, elastic rebound stage, free vibration stage in the position of the residual deformation.

Locomotive Crash Energy Management Test Plans

2015 ◽  
Author(s):  
Patricia Llana
Keyword(s):  
Finite Element ◽  
New Technologies ◽  
Element Model ◽  
Individual Performance ◽  
Integrated System ◽  
Design Concept ◽  
Element Analysis ◽  
Vehicle To Vehicle ◽  
Working Together ◽  
The Impact

The Office of Research, Development, and Technology of the Federal Railroad Administration (FRA) and the Volpe Center are continuing to evaluate new technologies for increasing the safety of passengers and operators in rail equipment. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of the other vehicle, can be devastating. Crashworthy components which can be integrated into the end structure of a locomotive have been developed to inhibit override in the event of collision. Recent research has resulted in the development of a design concept, including evaluation with finite-element analysis (FEA), fabrication, and component tests. The design concept developed incorporates two key components: a push-back coupler and a deformable anti-climber. Detailed designs for these components were developed and the performance of the designs was evaluated through large deformation dynamic FEA. Test articles were fabricated and dynamically tested to verify their individual performance characteristics. The tests were successful in demonstrating the required performance of the components. Test results were consistent with finite element model predictions of energy absorption capability, force-displacement behavior, and modes of deformation. Work is ongoing to retrofit these crashworthy components onto conventional locomotives and conduct full-scale dynamic impact tests of colliding cars, as well as colliding trains. Service tests will be performed to measure the impact speed at which push-back coupler triggering occurs. Vehicle-to-vehicle tests will be conducted to demonstrate the performance of the crashworthy components working together as an integrated system. The vehicle-to-vehicle tests will also allow an evaluation of the crashworthiness compatibility of a modified locomotive with a range of equipment, including conventional locomotives, cab cars, and freight cars. Train-to-train tests are planned to demonstrate incremental improvement, increased crashworthiness, compatibility, and serviceability. This paper describes the tests that are planned to demonstrate the behavior of these components when they are integrated into the end structure of a locomotive. The tests will demonstrate the in-service and crashworthiness performance of the modified locomotives. This research program endeavors to advance locomotive crashworthiness technology and develop the technical basis for generating specifications for push-back couplers and deformable anti-climbers.

scholarly journals Design and analysis of demolition robot arm based on finite element method

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985396 ◽  
Author(s):  
Jiong Li ◽  
Yu Wang ◽  
Kai Zhang ◽  
Zhiqiao Wang ◽  
Jiaxing Lu
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Impact Force ◽  
Second Order ◽  
Robot Arm ◽  
Element Analysis ◽  
Front End ◽  
The Finite Element Analysis ◽  
The Impact ◽  
Ansys Workbench

As a novel robot which mainly engages in the demolition and transformation of various concrete buildings, the demolition robot has developed rapidly in recent years. The impact force is mainly produced by the breaking hammer installed in the front end of the arm. As the most important part of a demolition robot, the boom arm is mainly composed of four parts including a supporting arm, a main arm, a fore arm, and a breaking hammer system. In this article, a mechanical model of the boom arm is established, and the finite element analysis obtaining the first four-order natural frequencies and modes is carried out in ANSYS Workbench. The results reveal that the resonation can be easily stimulated when a hydraulic breaking hammer is at the second-order frequency. The mounting block of the hydraulic breaking hammer, the hinge parts of the supporting arm, and the main arm are easily deformed or damaged in the Y direction by analyzing the deformation in three directions of the second-order mode. After the structure optimization, the vibration characteristics of the two parts are significantly enhanced, which provides a theoretical basis for optimizing the prototype and gives a reference in the experimental modes.

Finite Element Analysis of a Close Head Axonal Injury Model: Relating Brain Tissue Biomechanics to Skull Deformation

2008 ◽  
Author(s):  
Haojie Mao ◽  
Liying Zhang ◽  
King H. Yang ◽  
Albert I. King ◽  
J’ozsef Pál ◽  
...  
Keyword(s):  
Finite Element ◽  
Compressive Strain ◽  
Axonal Injury ◽  
Element Model ◽  
Element Analysis ◽  
Injury Model ◽  
Weight Drop ◽  
Biomechanical Responses ◽  
Histological Results ◽  
The Impact

Biomechanical responses of a rat brain in a new weight-drop model were investigated by comparing histological results against finite element model predictions. This graded axonal injury rat model differed from others because of its utilization of intact skull without global angular motion to confound data analyses. Results demonstrated that the maximum principal strain and the compressive strain along the impact direction best correlated the experimentally observed injury locations while the shear strain did not have positive correlation.

Study of Ship-Ice Collision on Ice Breaker ARAON

2014 ◽  
Author(s):  
Sungchan Kim ◽  
Insik Nho ◽  
Takkee Lee ◽  
Kyungsik Choi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Impact Force ◽  
Structural Response ◽  
Element Model ◽  
Design Data ◽  
Complex Process ◽  
The Impact ◽  
Interaction Behaviors ◽  
Ship Speed

The interaction between a ship and sea ice is a complex process depending on the ice properties, the ice geometry and the relative velocity between the ship and the ice. The effect of important parameters such as ship speed and ice thickness on the impact force are studied by means of finite element model. Idealized ice element types are applied to finite element model in order to survey the impact force and the structural response of icebreaker ARAON subjected to sea ices. Interaction behaviors obtained by finite element model considering the varying parameters are also discussed to compare the numerical results with the design data of ARAON.

Finite Element Analysis and Testing of Ladle Turret’s Supporting Arm

2012 ◽  
Vol 433-440 ◽  
pp. 5896-5901
Author(s):  
Li Kun Guan ◽  
Xin Yu Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Analytical Study ◽  
Site Response ◽  
Element Model ◽  
Accurate Information ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Impact Coefficient ◽  
The Impact

Objective: To establish a finite element model for ladle turret’s supporting arm. Verify the accuracy of finite element analysis, and accurate information cause of crack. Methods: Use ANSYS finite element analysis software to perform a solution of the supporting arm at loaded full ladle . By mean of strain measuements ,impact coefficient was obtained,and presents an analytical study of static strength of the supporting arm. Result:The greater the load is, the smaller the impact factor is. Verify the accuracy of the finite element method by on-site response test. Accordingly, it improves the supporting arm on the structure by effective basis.

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