Effect of Multi-Material Substitutions on Static and Dynamic Properties of Electric Vehicles

2012 ◽  
Vol 535-537 ◽  
pp. 1402-1407
Author(s):  
Li Li Yu ◽  
Zhen Hua Su ◽  
Jing Zhan Lin ◽  
Yu Sen Yuan ◽  
Chun Xiang Cui ◽  
...  
Keyword(s):  
Weight Reduction ◽  
Dynamic Properties ◽  
Product Performance ◽  
Fe Model ◽  
Performance Targets ◽  
Exciting Frequency ◽  
Strength And Stiffness ◽  
Aluminum And Magnesium Alloys ◽  
Bending Loading ◽  
Better Than

Automotive weight reduction is a challenging task due to many performance targets that must be satisfied simultaneously, in particular in terms of static and dynamic properties direct relating to strength, stiffness and NVH characteristics of vehicles. Compared to all-steel vehicle frame, multi-material substitutions are adopted in each structural component for higher product performance and a lightweight electric vehicle frame in this paper. The SHELL63 element is selected to construct finite element (FE) model of vehicle frame based on the FEA software ANSYS. Under full bending loading and torsional loading respectively, static analysis of frame is performed, and the strength and stiffness are evaluated as well. The Block Lanczos is adopted for dynamic analysis of vehicle frame. Their first eight modal properties are obtained and far away exciting frequency range of rough road. The multi-material vehicle frame has been designed to be made of mild steel, aluminum and magnesium alloys. Its static and dynamic properties show that the strength, stiffness and NVH characteristics are better than ones from all-steel vehicle frame with weight reduction of 31.7%. These procedures will help to design a lightweight and thus to provide technical support for reducing fuel consumption and greenhouse gas emissions.

Managing Flow Induced Vibration in Subsea Jumpers

2021 ◽  
Author(s):  
Rakshith Naik ◽  
Yetzirah Urthaler ◽  
Scot McNeill ◽  
Rafik Boubenider
Keyword(s):  
Dynamic Properties ◽  
Fatigue Analysis ◽  
Management Program ◽  
Measured Data ◽  
Operating Conditions ◽  
Valuable Insight ◽  
Fe Model ◽  
Flow Induced Vibration ◽  
Vibration Measurements

Abstract Certain subsea jumper design features coupled with operating conditions can lead to Flow Induced Vibration (FIV) of subsea jumpers. Excessive FIV can result in accumulation of allowable fatigue damage prior to the end of jumper service life. For this reason, an extensive FIV management program was instated for a large development in the Gulf of Mexico (GOM) where FIV had been observed. The program consisted of in-situ measurement, modeling and analysis. Selected well and flowline jumpers were outfitted with subsea instrumentation for dedicated vibration testing. Finite Element (FE) models were developed for each jumper and refined to match the dynamic properties extracted from the measured data. Fatigue analysis was then carried out using the refined FE model and measured response data. If warranted by the analysis results, action was taken to mitigate the deleterious effects of FIV. Details on modeling and data analysis were published in [5]. Herein, we focus on the overall findings and lessons learned over the duration of the program. The following topics from the program are discussed in detail: 1. In-situ vibration measurement 2. Overall vibration trends with flow rate and lack of correlation of FIV to flow intensity (rho-v-squared); 3. Vibration and fatigue performance of flowline jumpers vs. well jumpers 4. Fatigue analysis conservatism Reliance on screening calculations or predictive FE analysis could lead to overly conservative operational limits or a high degree of fatigue life uncertainty in conditions vulnerable to FIV. It is proposed that in-situ vibration measurements followed by analysis of the measured data in alignment with operating conditions is the best practice to obtain a realistic understanding of subsea jumper integrity to ensure safe and reliable operation of the subsea system. The findings from the FIV management program provide valuable insight for the subsea industry, particularly in the areas of integrity management of in-service subsea jumpers; in-situ instrumentation and vibration measurements and limitations associated with predictive analysis of jumper FIV. If learnings, such as those discussed here, are fed back into design, analysis and monitoring guidelines for subsea equipment, the understanding and management of FIV could be dramatically enhanced compared to the current industry practice.

Correlation Study on Modal Frequency and Temperature Effects of a Cable-Stayed Bridge Model

2012 ◽  
Vol 446-449 ◽  
pp. 3264-3272 ◽  
Author(s):  
Li Min Sun ◽  
Yi Zhou ◽  
Xue Lian Li
Keyword(s):  
Experimental Study ◽  
Boundary Conditions ◽  
Dynamic Properties ◽  
Bridge Engineering ◽  
Fe Model ◽  
Steel Cable ◽  
Transverse Beam ◽  
Expansion Joints ◽  
Cable Stayed Bridge ◽  
Bridge Model

In recent years, structural health monitoring has been paid more and more attention in bridge engineering community. Previous researches showed that ambient temperature was one of principal factors affecting structural modal parameters in long-term. In this paper, an experimental study on correlation between dynamic properties of a cable-stayed bridge and its structural temperature was performed under temperature controlled laboratory environment. Using hammer impacting method, a dynamic testing was conducted based on a steel cable-stayed bridge model which had a span layout of 0.9+1.9+0.9m. During the experiment, the first six vertical bending modes under the environmental temperature of 0, 20 and 40°C were identified with the consideration of three kinds of boundary conditions at the deck’s ends as to two degrees of freedom, i.e. the longitudinal translation (UX) and the rotation about the transverse beam (RotZ). The above boundary conditions are UX & RotZ not constrained, UX constrained only and UX & RotZ constrained, attempting to simulate the different conditions of the bridge expansion joints. The efforts were paid to explain the physical mechanism of the results based on the updated FE model. This experimental study indicates a tendency that the frequency of the cable-stayed bridge model decreases with the increase of temperature. And furthermore, the relative difference of frequencies between 0 and 40 °C is affected by boundary conditions; in other words, when the deck is free to expand, the variation of model’s frequencies is smaller than that when the deck is restrained to expand, which is similar to the condition of the bridge’s expansion joints cannot work as normal. This experimental study can give some reference to the research of SHM and damage identification for cable-stayed bridges.

Damping Behavior of Blades From Small Radial Turbines

2015 ◽  
Author(s):  
David Hemberger ◽  
Dietmar Filsinger ◽  
Hans-Jörg Bauer
Keyword(s):  
Numerical Analysis ◽  
Dynamic Properties ◽  
Forced Response ◽  
Operating Conditions ◽  
Fe Model ◽  
Structural Damping ◽  
Aerodynamic Damping ◽  
Damping Behavior ◽  
Aerodynamic Properties ◽  
Radial Turbines

Next to excitation forces and the dynamic properties of mistuned structures the damping behavior is a key feature to evaluate the dynamic turbine blade response and thus the HCF life of a bladed disk (blisk). Just as the determination of the mistuning properties and the assessment of the vibration excitation, the evaluation of damping is also subject to uncertainty especially considering the wide operating range of a small radial turbine of a turbocharger. Since the total damping is composed of material damping, structural damping and aerodynamic damping, which are affected by parameters, like the eigenform of the vibration, the magnitude of the vibration amplitude and aerodynamic properties, the total damping can be strongly dependent on the operating conditions. The study at hand provides results from investigations that allow estimating the contribution of aerodynamic damping on the total damping. Experimental and numerical analysis of radial turbines from turbochargers for vehicular engines with variable turbine inlet vanes were performed. Measurements under different environmental conditions such as at rest and during operation, as well as unsteady CFD calculations and, coupled flow and structural calculations were carried out. A change in total damping could be found depending on the density of the surrounding gas by vibration measurements in operation on the hot gas test bench. But it was also shown that the total damping is decisively influenced by the mistuning of the structure. On one side the structural damping is varied by the variation in mistuned blade vibration amplitudes and otherwise the aerodynamic damping is influenced by the different inter blade phase angles (IBPA ) due to the mistuning, which is a symptom of geometric differences and material inhomogeneity in the wheels. Finally, the estimated total damping values were utilized in forced response calculations using a mistuned FE-model of a real turbine and excitation forces from unsteady CFD calculation. The magnitudes of the measured vibration amplitudes were compared with results from numerical analysis to validate the numerical model with focus on the investigation about the total damping. The deviation between the results was ±10% for different eigenforms and excitation orders.

Strength and Stiffness Degradation of Carbon Fiber Reinforced Plastic under Cyclic Loading under Membran-, Shear- and Bending Loading

2015 ◽  
Vol 825-826 ◽  
pp. 968-975
Author(s):  
Peter Haefele ◽  
Oscar Herrera
Keyword(s):  
Carbon Fiber ◽  
Cyclic Loading ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Operational Conditions ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced ◽  
Strength And Stiffness ◽  
Bending Loading

In order to meet the increasing lightweight requirements, the application of fiber reinforced plastics is indispensable. To ensure the structural durability of the car or machine under operational conditions, it is essential to know the long term behavior of carbon fiber reinforced plastic material (CFRP) under the numerous influencing factors under fatigue loading. For a reliable safety assessment of the car structure under operational conditions, the degradation of the stiffness and of the static strength after a certain damage due to cyclic loading is of particular importance. The paper covers the loss of stiffness and remaining strength as a function of fatigue damage for specimen and components under membrane, shear and bending loading. The tests are done using different layer set-ups (unidirectional, angle ply, quasiisotropic) and various loading conditions (membrane, shear and bending loading). In order to account for the transferability, the tests are carried out using specimen and components (hat sections). Both specimen and components show a significant loss in strength and stiffness.

Numerical Analysis and Mechanical Properties of Nomex™ Honeycomb Core

2017 ◽  
Author(s):  
Yue Liu ◽  
Weicheng Gao ◽  
Wei Liu ◽  
Zhou Hua
Keyword(s):  
Compressive Strength ◽  
Cell Walls ◽  
Mechanical Response ◽  
Compressive Loading ◽  
Fe Model ◽  
Honeycomb Core ◽  
Practical Applications ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb ◽  
Strength And Stiffness

This paper presents an investigation on the mechanical response of the Nomex honeycomb core subjected to flatwise compressive loading. Thin plate elastic in-plane compressive buckling theory is used to analyze the Nomex honeycomb core cell wall. A mesoscopic finite element (FE) model of honeycomb sandwich structure with the Nomex honeycomb cell walls is established by employing ABAQUS/Explicit shell elements. The compressive strength and compressive stiffness of Nomex honeycomb core with different heights and thickness of cell walls, i.e. double cell walls and single cell walls, are analyzed numerically using the FE model. Flatwise compressive tests are also carried out on bare honeycomb cores to validate the numerical method. The results suggest that the compressive strength and compression stiffness are related to the geometric dimensions of the honeycomb core. The Nomex honeycomb core with a height of 6 mm has a higher strength than that of 8 mm. In addition, the honeycomb core with lower height possesses stronger anti-instability ability, including the compressive strength and stiffness. The proposed mesoscopic model can effectively simulate the crushing process of Nomex honeycomb core and accurately predict the strength and stiffness of honeycomb sandwich panels. Our work is instructive to the practical applications in engineering.

Experimental study on the seismic performance of traditional timber mortise-tenon joints with different looseness under low-cyclic reversed loading

2018 ◽  
Vol 22 (6) ◽  
pp. 1312-1328 ◽  
Author(s):  
Jianyang Xue ◽  
Rui Guo ◽  
Liangjie Qi ◽  
Dan Xu
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Failure Modes ◽  
Artificial Defect ◽  
Reversed Loading ◽  
Energy Dissipation Capacity ◽  
Strength And Stiffness ◽  
Seismic Behaviors ◽  
Damage Type ◽  
Better Than

The majority of existing ancient timber structures have different degrees of damage. The looseness of mortise-tenon joints is a kind of typical damage type. In order to study the influence of looseness on the seismic performance of mortise-tenon joints, six through-tenon joints and six dovetail-tenon joints with scale 1:3.2 were fabricated according to the requirements of the engineering fabrication method of Chinese Qing Dynasty. Each type of joints consisted of one intact joint and five artificial loose joints, and the artificial defect was made to simulate looseness by cutting the tenon sectional dimension. Based on experiments of two types of joints under low-cyclic reversed loading, the seismic behaviors of joints such as failure modes, hysteretic loops and skeleton curves, strength and stiffness degradation, and energy dissipation capacity were studied. Moreover, the comparative analyses of seismic performance between two types of joints were carried out. The variation tendency of seismic behaviors of two types of joints has similarities, and there are some differences due to their different structural styles. The results indicate that squeeze deformation between tenon and mortise of two types of joints occurred. The shape of hysteretic loops of two types of joints is reverse-Z-shape, and the pinching effect of hysteretic loops becomes more obvious with the increase in looseness, among which of through-tenon joints is more obvious than that of dovetail-tenon joints. The carrying capacity, stiffness, and energy dissipation capacity of loose joints are significantly lower than that of the intact one, and the energy dissipation capacity of dovetail-tenon joints is better than that of through-tenon joints. The rotation angles of two types of joints can reach 0.12 rad, and the loose joints still have great deformation capacity.

VIBRATION OF CIRCULAR BLADED DISK WITH IMPERFECTIONS

2011 ◽  
Vol 21 (10) ◽  
pp. 2893-2904 ◽  
Author(s):  
LADISLAV PŮST ◽  
LUDĚK PEŠEK
Keyword(s):  
Dynamic Properties ◽  
Single Point ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Fe Model ◽  
Rotating Disks ◽  
Response Curves ◽  
State Response ◽  
Bladed Disk ◽  
Linear Damping

The steady state response of a model of circular bladed disk with imperfection is investigated. Disk imperfection results from additional two groups of damping heads fixed on opposite ends of one diameter. These damping heads are introduced into the computing model as additional point mass, damping and stiffness. Such type of imperfection causes the bifurcation of double eigenfrequencies into pairs of close eigenfrequencies. The effect of imperfection is examined both numerically on three-dimensional nonrotating FE-model and analytically on a simplified split 2DOF model of rotating disk excited by single point harmonic force. Nonlinear friction connection is analyzed and equivalent linear damping coefficient is derived and used in the calculation procedure. It is shown that nonproportional distribution of damping strongly influences the high of resonance peaks. Some examples of response curves illustrate the dynamic properties of stationary and rotating disks with mass-damping-stiffness imperfection.

Fatigue Analysis of Rail-Head-to-Web Fillet at Bolted Rail Joint Under Various Impact Wheel Load Factors and Support Configurations

2016 ◽  
Author(s):  
Kaijun Zhu ◽  
J. Riley Edwards ◽  
Yu Qian ◽  
Bassem O. Andrawes
Keyword(s):  
Fatigue Life ◽  
Fe Model ◽  
Wheel Load ◽  
Transit Systems ◽  
University Of Illinois ◽  
Rail Head ◽  
Load Factors ◽  
Continuous Welded Rail ◽  
The University ◽  
Better Than

As one of the weakest locations in the track superstructure, the rail joint encounters different types of defects and failures, including rail bolt-hole cracking, rail head-web cracking or separation, broken or missing bolts, and joint bar cracking. The defects and failures are mainly initiated by the discontinuities of both geometric and mechanical properties due to the rail joint, and the high impact loads induced by the discontinuities. Continuous welded rail (CWR) overcomes most disadvantages of the rail joints. However, a large number of rail joints still exist in North American Railroads for a variety of reasons, and bolted joints are especially prevalent in early-built rail transit systems. Cracks are often found to initiate in the area of the first bolt-hole and rail-head-to-web fillet (upper fillet) at the rail end among bolted rail joints, which might cause further defects, such as rail breaks or loss of rail running surface. Previous research conducted at the University of Illinois at Urbana-Champaign (UIUC) has established an elastic static Finite Element (FE) model to study the stress distribution of the bolted rail joint with particular emphasis on rail end bolt-hole and upper fillet areas. Based on the stress calculated from the FE models, this paper focuses on the fatigue performance of upper fillet under different impact wheel load factors and crosstie support configurations. Preliminary results show that the estimated fatigue life of rail end upper fillet decreases as impact factor increases, and that a supported joint performs better than a suspended joint on upper fillet fatigue life.

NONLINEAR FINITE ELEMENT MODELING OF POST-TENSION RC AND RC BEAMS STRENGTHENED WITH NSM FRP RODS

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Belal Elharouney ◽  
Ayman Hussein ◽  
Ezz El-Deen Mostafa ◽  
Amr El-Nemr
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Load Capacity ◽  
Reinforced Concrete Beam ◽  
Experimental Results ◽  
Fe Model ◽  
Post Tension ◽  
Bending Loading ◽  
Frp Bars

The post-tensioned (PT) reinforced beams can provide a fast construction advantage through precast and cast-in-situ structural elements. However, due to the excessive increase in load capacity, especially when it comes to girder of bridges, the strengthening using Fiber-reinforced polymer (FRP) might be a solution. Near-surface mounted (NSM) is one of the methods used in strengthening cases, especially in the case of non-degraded concrete cover. Furthermore, very few researchers visited this area experimentally, which consider cost-effective. In this paper, two finite element models using the Abaqus program validated experimental results for both Post-tension beam and strengthening of the beam using NSM separately as preliminary models for combining both systems. PT reinforced concrete beam subjected to four-point bending loading as well as reinforced concrete beam strengthened with NSM using FRP bars subjected to two-point bending loading examined and validated through a 3D non-linear finite element (FE) model to be compared by the experimental results. This FE model considered the non-linear constitutive properties of concrete, yielding of steel, and the bond between strand, concrete, and FRP bars at NSM. The models were targeting the strengthening of existing Post tension girder beams of existing bridges structures. These modeling results showed a reasonable agreement with the tested beam results in terms of failure modes, the load capacity, load-deflection curve, and cracking behavior.

Strength and Deformation Capacity of Corroded Pipes: The Joint Industry Project

2013 ◽  
Author(s):  
Erik Levold ◽  
Andrea Restelli ◽  
Lorenzo Marchionni ◽  
Caterina Molinari ◽  
Luigino Vitali
Keyword(s):  
Failure Modes ◽  
State Of The Art ◽  
Local Buckling ◽  
Bending Moment ◽  
External Pressure ◽  
Fe Model ◽  
Deformation Capacity ◽  
Offshore Pipelines ◽  
Strength And Deformation ◽  
Bending Loading

Considering the future development for offshore pipelines, moving towards difficult operating condition and deep/ultra-deep water applications, there is the need to understand the failure mechanisms and better quantify the strength and deformation capacity of corroded pipelines considering the relevant failure modes (collapse, local buckling under internal and external pressure, fracture / plastic collapse etc.). A Joint Industry Project sponsored by ENI E&P and Statoil has been launched with the objective to quantify and assess the strength and deformation capacity of corroded pipes in presence of internal overpressure and axial/bending loading. In this paper: • The State-of-the-Art on strength and deformation capacity of corroded pipes is presented; • The full-scale laboratory tests on corroded pipes under bending moment dominated load conditions, performed at C-FER facilities, are shown together with the calibrated ABAQUS FE Model; • The results of the ABAQUS FEM parametric study are presented.

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