Modal and Transient Response Analysis for Complex Gear-Bearing System

2011 ◽  
Vol 130-134 ◽  
pp. 1152-1155 ◽  
Author(s):  
Jian Li Ge ◽  
Guo Lai Yang ◽  
Jian Wei Hao
Keyword(s):  
Numerical Solutions ◽  
Impact Load ◽  
Response Analysis ◽  
Fe Model ◽  
Similar System ◽  
Shell Elements ◽  
Hexahedral Elements ◽  
Stress And Deformation ◽  
Stiffness And Damping ◽  
Bearing System

The radar antenna pedestal is a complex gear-bearing system including three rotary motions, i.e. horizontal rolling, pitching rotation and azimuth rotation. In this paper, spring-dashpot elements and connection elements are applied to simulate gear meshing and bearing connection respectively. Moreover, the equivalent average stiffness and damping of teeth meshing and bearing connection are calculated. Then, quadrilateral shell elements, hexahedral elements, wedgy elements, connection elements and spring-dashpot elements are employed to build the finite element (FE) model of the gear-bearing system in Hypermesh software. Via intermediate file, the model is imported into ABAQUS software for modal analysis whose solutions agree well with experimental data. Then, impact acceleration is imposed on the three bolts of the underpan along the x-axis, y-axis and z-axis respectively. Dynamic stress distribution and regulation changing with time under impact load are obtained. From the numerical solutions, the regions where stress and deformation is lager are found. The method can provide significant reference to analysis and optimum design of the similar system.

BIOMECHANICAL RESPONSE AND INJURY OF OCCUPANT'S PELVIS IN SIDE IMPACTS: EFFECTS OF THE FEMORAL HEAD AND LOADING CONDITIONS

2014 ◽  
Vol 14 (06) ◽  
pp. 1440001
Author(s):  
ZHENGWEI MA ◽  
JIQING CHEN ◽  
FENGCHONG LAN
Keyword(s):  
Femoral Head ◽  
Impact Force ◽  
Impact Load ◽  
Human Subjects ◽  
Pelvic Injury ◽  
Fe Model ◽  
Side Impacts ◽  
Hexahedral Elements ◽  
Ct Data ◽  
Peak Impact Force

The occupant's pelvis is most susceptible to injuries in side collision accidents. To further investigate the pelvis biomechanical responses and injury mechanisms in side impacts, a biofidelic pelvis finite element (FE) model was created. In contrast to previous studies, the model was based directly on the CT data of a volunteer representing the 50th percentile Chinese male. Both cortical and cancellous bone were modeled with hexahedral elements. Through model validations against Post Mortem Human Subjects (PMHS) tests, the pelvis responses and injuries under side impacts were analyzed. Meanwhile, additional simulations were carried out utilizing the validated model to study the effects of the femoral head, impactor pad and impactor velocity on pelvic injuries. The results indicated that the most frequent injury type of the pelvis is pubic rami fracture, followed by fractures of the femoral head, greater trochanter and acetabulum. In validation against the test of Guillemot et al., the critical load of pelvic fracture was 3.8 kN. In validation against the tests of Beason et al., the peak impact force under unpadded load and padded load was 4.3 kN and 3.1 kN, respectively, while the (VC)max was 0.25 m/s and 0.16 m/s, respectively. Peak impact force appears to be a reasonable criterion to assess pelvic injury. Moreover, the femoral head and impactor pad play an important role in absorbing impact energy, distributing impact load, and alleviating pelvic injury.

scholarly journals An Algebraic Approach for Identification of Rotordynamic Parameters in Bearings with Linearized Force Coefficients

Mathematics ◽  
2021 ◽  
Vol 9 (21) ◽  
pp. 2747
Author(s):  
José Gabriel Mendoza-Larios ◽  
Eduardo Barredo ◽  
Manuel Arias-Montiel ◽  
Luis Alberto Baltazar-Tadeo ◽  
Saulo Jesús Landa-Damas ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Algebraic Approach ◽  
Rotational Inertia ◽  
Fe Model ◽  
Rotordynamic Coefficients ◽  
Rotor Bearing ◽  
Identification Technique ◽  
Stiffness And Damping ◽  
The Mathematical Model ◽  
Bearing System

In this work, a novel methodology for the identification of stiffness and damping rotordynamic coefficients in a rotor-bearing system is proposed. The mathematical model for the identification process is based on the algebraic identification technique applied to a finite element (FE) model of a rotor-bearing system with multiple degree-of-freedom (DOF). This model considers the effects of rotational inertia, gyroscopic moments, shear deformations, external damping and linear forces attributable to stiffness and damping parameters of the supports. The proposed identifier only requires the system’s vibration response as input data. The performance of the proposed identifier is evaluated and analyzed for both schemes, constant and variable rotational speed of the rotor-bearing system, and numerical results are obtained. In the presented results, it can be observed that the proposed identifier accurately determines the stiffness and damping parameters of the bearings in less than 0.06 s. Moreover, the identification procedure rapidly converges to the estimated values in both tested conditions, constant and variable rotational speed.

Finite Element Analysis of the Distributed Vibration Absorbers for Structural Noise Control

2005 ◽  
Author(s):  
Ashwini Gautam ◽  
Chris Fuller ◽  
James Carneal
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Base Plate ◽  
Element Model ◽  
Fe Model ◽  
Vibration Absorbers ◽  
Element Analysis ◽  
Poroelastic Media ◽  
Hexahedral Elements ◽  
Component Models

This work presents an extensive analysis of the properties of distributed vibration absorbers (DVAs) and their effectiveness in controlling the sound radiation from the base structure. The DVA acts as a distributed mass absorber consisting of a thin metal sheet covering a layer of acoustic foam (porous media) that behaves like a distributed spring-mass-damper system. To assess the effectiveness of these DVAs in controlling the vibration of the base structures (plate) a detailed finite elements model has been developed for the DVA and base plate structure. The foam was modeled as a poroelastic media using 8 node hexahedral elements. The structural (plate) domain was modeled using 16 degree of freedom plate elements. Each of the finite element models have been validated by comparing the numerical results with the available analytical and experimental results. These component models were combined to model the DVA. Preliminary experiments conducted on the DVAs have shown an excellent agreement between the results obtained from the numerical model of the DVA and from the experiments. The component models and the DVA model were then combined into a larger FE model comprised of a base plate with the DVA treatment on its surface. The results from the simulation of this numerical model have shown that there has been a significant reduction in the vibration levels of the base plate due to DVA treatment on it. It has been shown from this work that the inclusion of the DVAs on the base plate reduces their vibration response and therefore the radiated noise. Moreover, the detailed development of the finite element model for the foam has provided us with the capability to analyze the physics behind the behavior of the distributed vibration absorbers (DVAs) and to develop more optimized designs for the same.

Dynamic Response of a Generic Vehicle Floor Model to Coupled Transient Loads

1996 ◽  
Author(s):  
Aaron D. Gupta
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Response Analysis ◽  
Impact Loads ◽  
Valuable Insight ◽  
Concentrated Load ◽  
Shell Elements ◽  
Transient Loads ◽  
Method Of Evaluation ◽  
The Impact

Abstract A dynamic elastic large displacement response analysis of the bottom floor of a generic vehicle hull model subjected to empirically obtained coupled blast and impact loads has been conducted using three-dimensional (3-D) shell elements in the ADINA nonlinear dynamic finite element analysis code. For the impulse-dominated problem, the impact load is a square wave step function concentrated load while the blast loads from the detonation of an explosive are a series of distributed pressure loads approximated as triangular impulse loads with linear decay and varying arrival and duration times. The 3-D numerical model has been generated using the PATRAN3 modeling code and converted to the ADINA finite element input data deck using the ADINA translator and careful inclusion of appropriate material properties as well as initial and boundary conditions. Monolithic single-layered four-noded quad shell elements were sufficient to model the bottom floor and the left- and right-horizontal and vertical sponsons as well as the lower front glacis. Although several simplifying assumptions and approximations are made during the generation of the basic floor model, material properties, and the forcing functions, the investigation gives valuable insight into the response behavior of a generic hull bottom floor to externally applied coupled blast and impact loads and provides an inexpensive nondestructive method of evaluation of the structural integrity of modern vehicles subjected to spatially varying transient loads.

Frequency Response Analysis of Damped Dual Mass Flywheel

2015 ◽  
Vol 724 ◽  
pp. 271-274 ◽  
Author(s):  
Rong Zeng ◽  
Zheng Feng Jiang ◽  
Xing Wan
Keyword(s):  
Frequency Response ◽  
Piecewise Linear ◽  
Vibration Damping ◽  
Torsional Stiffness ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Power Train ◽  
Detail Design ◽  
Stiffness And Damping ◽  
Sinusoidal Excitation

s:Aiming at circumferential arc spring dual mass flywheel (CSDMF), this paper carries out analysis on the piecewise linear model and calculates the frequency response of damped model under sinusoidal excitation. Being combined with the calculate results, the research respectively analyzes the value of inertia ratio, torsional stiffness and damping parameters. The analysis results show that the greater the damping, inertia ratio of primary and secondary flywheels are, the torsional stiffness, the more obvious vibration damping of the dual mass flywheel would be. To meet the vibration damping requirements, the detail design of the three parameters need to be combined with power train and the torsion characteristic of CSDMF.

Two-Dimensional Nonlinear Earthquake Response Analysis of a Bridge-Foundation-Ground System

2008 ◽  
Vol 24 (2) ◽  
pp. 343-386 ◽  
Author(s):  
Yuyi Zhang ◽  
Joel P. Conte ◽  
Zhaohui Yang ◽  
Ahmed Elgamal ◽  
Jacobo Bielak ◽  
...  
Keyword(s):  
Lateral Spreading ◽  
Soil Liquefaction ◽  
Earthquake Response ◽  
Response Analysis ◽  
Fe Model ◽  
Two Dimensional ◽  
Foundation Soil ◽  
Soil Medium ◽  
Surface Plasticity ◽  
Earthquake Response Analysis

This paper presents a two-dimensional advanced nonlinear FE model of an actual bridge, the Humboldt Bay Middle Channel (HBMC) Bridge, and its response to seismic input motions. This computational model is developed in the new structural analysis software framework OpenSees. The foundation soil is included to incorporate soil-foundation-structure interaction effects. Realistic nonlinear constitutive models for cyclic loading are used for the structural (concrete and reinforcing steel) and soil materials. The materials in the various soil layers are modeled using multi-yield-surface plasticity models incorporating liquefaction effects. Lysmer-type absorbing/transmitting boundaries are employed to avoid spurious wave reflections along the boundaries of the computational soil domain. Both procedures and results of earthquake response analysis are presented. The simulation results indicate that the earthquake response of the bridge is significantly affected by inelastic deformations of the supporting soil medium due to lateral spreading induced by soil liquefaction.

scholarly journals Design and Structural Analysis of a Rack System for Using in Agriculture

2018 ◽  
Vol 66 (3) ◽  
pp. 641-646
Author(s):  
Miroslav Blatnický ◽  
Ján Dižo ◽  
Dalibor Barta
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Analysis ◽  
Fe Model ◽  
Steel Tubes ◽  
Shell Elements ◽  
Human Power ◽  
Construction Design ◽  
Pull Out ◽  
Pressure Pipeline

The paper deals with a construction design and structural analysis of the rack system which will be used for storage of steel tubes of pressure pipeline for fodder mixtures transportation in agricultural company. Structure of the designed equipment is made by the welding of steel parts and consists of the main framework and four pull-out racks on both sides. Racks move by means of human power through a rotating crank. Every individual pull-out racks is able to carries pipes of various dimensions, both length and diameter with total weight up to 3 tons with respect to customer requests. Since it is a prototype’s structure, we have designed main dimensions of it, material and technology for production and performed also structural analyses as the integral part of every engineering design. Structural analyses were conducted by means of numeric procedure known as finite element method. With respect to the used steel profiles shell elements were used for FE model. Analyses were performed for maximal loading cases in order to identify the level of safety in the most exposed locations of the structure.

scholarly journals Numerical Simulation of Dynamic Response and Evaluation of Flexural Damage of RC Columns under Horizontal Impact Load

2021 ◽  
Vol 11 (23) ◽  
pp. 11223
Author(s):  
Bin Hu ◽  
Jian Cai ◽  
Jiabin Ye
Keyword(s):  
Static Load ◽  
Impact Load ◽  
Bending Moment ◽  
Internal Force ◽  
Displacement Curve ◽  
Fe Model ◽  
Damage State ◽  
Rc Columns ◽  
Equivalent Static Load ◽  
The Impact

By using the ABAQUS finite element (FE) model, which has been verified by experiments, the deformation and internal force changes of RC columns during the impact process are investigated, and a parametric analysis is conducted under different impact kinetic energies Ek. According to the development path of the bottom bending moment-column top displacement curve under impact, the member is in a slight damage state when the curve rebounds before reaching the peak and in a moderate or severe damage state when the curve exceeds the peak, in which case the specific damage state of the member needs to be determined by examining whether there is a secondary descending stage in the curve. Accordingly, a qualitative method for evaluating the bending failure of RC column members under impact is obtained. In addition, the damage state of RC columns under impact can also be quantitatively evaluated by the ratio of the equivalent static load Feq and the ultimate static load-bearing capacity Fsu.

scholarly journals New Design Concept for Bridge Restrainers with Rubber Cushion Considering Dynamic Action: A Preliminary Study

2020 ◽  
Vol 10 (19) ◽  
pp. 6847
Author(s):  
Hiroki Tamai ◽  
Chi Lu ◽  
Yoichi Yuki
Keyword(s):  
Design Concept ◽  
Seismic Retrofitting ◽  
Response Analysis ◽  
Fe Model ◽  
Dynamic Action ◽  
Current Design ◽  
Coupling Dynamic ◽  
Existing Bridges ◽  
Constituent Elements ◽  
Large Earthquakes

A bridge unseating prevention system is a safety system for bridge collapses caused by large earthquakes, beyond the assumption of aseismic design specifications. Presently, the system is generally adopted for newly constructed bridges and the seismic retrofitting of existing bridges. Cable type bridge restrainers are included in the system, and they are expected to prevent superstructures from exceeding the seat length of substructures. Although the bridge restrainer works during an earthquake, it is designed to be static in the current design. In addition, although the constituent elements of bridge restrainers include a rubber cushion to absorb energy during an earthquake, the effect is not included in the design. Thus, the current design lacks the dynamic effects of earthquakes and the cushioning effect of the rubber. Furthermore, in the case of a multi-span bridge, there is no particular decision as to where the restrainers should be placed or what kind of specifications they should have. Therefore, in this paper, a new design concept that considers the dynamic action of the earthquake and the cushioning effect of the rubber is proposed by coupling dynamic response analysis using a frame finite element (FE) model and a simple genetic algorithm (SGA).

scholarly journals ANALYTICAL AND EXPERIMENTAL STUDY ON REPAIR EFFECTIVENESS OF CFRP SHEETS FOR RC BEAMS

2013 ◽  
Vol 20 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Moatasem M. Fayyadh ◽  
H. Abdul Razak
Keyword(s):  
Experimental Study ◽  
Failure Modes ◽  
Load Capacity ◽  
Fe Model ◽  
Rc Beams ◽  
Shell Elements ◽  
Cfrp Sheets ◽  
Adhesive Interface ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

This paper presents the results of both analytical and experimental study on the repair effectiveness of Carbon Fibre Reinforced Polymer (CFRP) sheets for RC beams with different levels of pre-repair damage severity. It highlights the effect of fixing CFRP sheets to damaged beams on the load capacity, mid-span deflection, the steel strain and the CFRP strain and failure modes. The analytical study was based on a Finite Element (FE) model of the beam using brick and embedded bar elements for the concrete and steel reinforcement, respectively. The CFRP sheets and adhesive interface were modelled using shell elements with orthotropic material properties and incorporating the ultimate adhesive strain obtained experimentally to define the limit for debonding. In order to validate the analytical model, the FE results were compared with the results obtained from laboratory tests conducted on a control beam and three other beams subjected to different damage loads prior to repair with CFRP sheets. The results obtained showed good agreement, and this study verified the adopted approach of modelling the adhesive interface between the RC beam and the CFRP sheets using the ultimate adhesive strains obtained experimentally.

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