scholarly journals Approach to the numerical modelling of the chip temperatures in single grain scratching

2021 ◽  
Author(s):  
Thomas Bergs ◽  
Jannik Röttger ◽  
Sebastian Barth ◽  
Sebastian Prinz
Keyword(s):  
Experimental Validation ◽  
Numerical Models ◽  
Three Dimensional ◽  
Sufficient Accuracy ◽  
Experimental Investigations ◽  
Fe Model ◽  
Numerical Investigations ◽  
Physical Mechanisms ◽  
Fundamental Understanding ◽  
Single Grain

AbstractTo achieve a fundamental understanding of the physical mechanisms and the heat generation in the contact zone during grinding, a large number of experimental and numerical investigations have been carried out to analyse the interaction of single grain and workpiece. Existing numerical models of the interaction between grain and workpiece do not represent the reality and especially the influence of the three-dimensional grain geometry on the temperatures during single grain scratching with sufficient accuracy. An experimental validation of the simulated temperatures has not been carried out yet as there is no appropriate method to measure them in experimental investigations. In this study, a three-dimensional FE-model of the interaction between CBN-grain and workpiece (100Cr6) in the grinding process is presented. The model predicts the chip temperatures for real grain geometries to investigate the interactions between grain and workpiece. The experiments to validate the model were carried out using a ratio pyrometer.

scholarly journals Established Numerical Techniques for the Structural Analysis of a Regional Aircraft Landing Gear

2018 ◽  
Vol 2018 ◽  
pp. 1-21 ◽  
Author(s):  
F. Caputo ◽  
A. De Luca ◽  
A. Greco ◽  
A. Marro ◽  
A. Apicella ◽  
...  
Keyword(s):  
Finite Elements ◽  
Numerical Models ◽  
Three Dimensional ◽  
Landing Gear ◽  
Point Of View ◽  
Fe Model ◽  
One Dimensional ◽  
Reaction Forces ◽  
Local Technique ◽  
Stick Model

Usually during the design of landing gear, simplified Finite Element (FE) models, based on one-dimensional finite elements (stick model), are used to investigate the in-service reaction forces involving each subcomponent. After that, the design of such subcomponent is carried out through detailed Global/Local FE analyses where, once at time, each component, modelled with three-dimensional finite elements, is assembled into a one-dimensional finite elements based FE model, representing the whole landing gear under the investigated loading conditions. Moreover, the landing gears are usually investigated also under a kinematic point of view, through the multibody (MB) methods, which allow achieving the reaction forces involving each subcomponent in a very short time. However, simplified stick (FE) and MB models introduce several approximations, providing results far from the real behaviour of the landing gear. Therefore, the first goal of this paper consists of assessing the effectiveness of such approaches against a 3D full-FE model. Three numerical models of the main landing gear of a regional airliner have been developed, according to MB, “stick,” and 3D full-FE methods, respectively. The former has been developed by means of ADAMS® software, the other two by means of NASTRAN® software. Once this assessment phase has been carried out, also the Global/Local technique has verified with regard to the results achieved by the 3D full-FE model. Finally, the dynamic behaviour of the landing gear has been investigated both numerically and experimentally. In particular, Magnaghi Aeronautica S.p.A. Company performed the experimental test, consisting of a drop test according to EASA CS 25 regulations. Concerning the 3D full-FE investigation, the analysis has been simulated by means of Ls-Dyna® software. A good level of accuracy has been achieved by all the developed numerical methods.

Experimental and Numerical Investigations of Tractive Performance of Off-Road Tires on Gravel Terrain

2019 ◽  
Vol 17 (08) ◽  
pp. 1950055 ◽  
Author(s):  
Haiyang Zeng ◽  
Wei Xu ◽  
Mengyan Zang ◽  
Peng Yang
Keyword(s):  
Finite Element ◽  
Numerical Models ◽  
Three Dimensional ◽  
Great Influence ◽  
Coupling Method ◽  
Experimental Device ◽  
Tractive Force ◽  
3D Finite Element ◽  
Numerical Investigations ◽  
Soil Bin

In this work, an indoor soil-bin is designed to investigate the tire–terrain interaction mechanisms for the off-road tires rolling on the gravel terrain. The soil-bin test is carried out by the indoor soil-bin experimental device and the three-dimensional (3D) finite element (FE) and discrete element (DE) coupling method under the same particles conditions, respectively. First, with the indoor soil-bin measurement system, the repeatability of the soil-bin experiments is employed to validate the experimental device and the numerical models. Moreover, the tractive performance experiments of the off-road tires with two tread patterns, smooth and grooved interacting with gravel terrain, are performed at the slip of 10%, 20% and 30%, respectively, to obtain the tractive force and the rim sinkage. Second, the corresponding numerical models are also established, and simulated by the FE–DE coupling method, where the FEM and the DEM are used to describe the off-road tires and the gravel terrain, respectively. The tractive mechanisms of the off-road tires in interaction with the gravel terrain such as the tractive force and the rim sinkage are investigated numerically. Meanwhile, The dynamics and discontinuity of the gravel assembly are described by the presented approach. Besides, both the results of the simulations and experiments indicate that tread patterns and slip conditions have great influence on the tire tractive performance. Finally, the numerical simulations and the experimental results qualitatively show good agreements, which certifies the effectiveness of the FE–DE coupling method in the tractive performance analysis of tire–gravel terrain interactions.

scholarly journals The Fluid-Solid Interaction Dynamics between Underwater Explosion Bubble and Corrugated Sandwich Plate

2016 ◽  
Vol 2016 ◽  
pp. 1-21
Author(s):  
Hao Wang ◽  
Yuan Sheng Cheng ◽  
Jun Liu ◽  
Lin Gan
Keyword(s):  
Shock Wave ◽  
Failure Modes ◽  
Sandwich Structures ◽  
Numerical Models ◽  
Near Field ◽  
Three Dimensional ◽  
Underwater Explosion ◽  
Bubble Collapse ◽  
Fe Model ◽  
Wave Load

Lightweight sandwich structures with highly porous 2D cores or 3D (three-dimensional) periodic cores can effectively withstand underwater explosion load. In most of the previous studies of sandwich structure antiblast dynamics, the underwater explosion (UNDEX) bubble phase was neglected. As the UNDEX bubble load is one of the severest damage sources that may lead to structure large plastic deformation and crevasses failure, the failure mechanisms of sandwich structures might not be accurate if only shock wave is considered. In this paper, detailed 3D finite element (FE) numerical models of UNDEX bubble-LCSP (lightweight corrugated sandwich plates) interaction are developed by using MSC.Dytran. Upon the validated FE model, the bubble shape, impact pressure, and fluid field velocities for different stand-off distances are studied. Based on numerical results, the failure modes of LCSP and the whole damage process are obtained. It is demonstrated that the UNDEX bubble collapse jet local load plays a more significant role than the UNDEX shock wave load especially in near-field underwater explosion.

A Three-Dimensional Human Trunk Model for the Analysis of Respiratory Mechanics

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Michel Behr ◽  
Jeremie Pérès ◽  
Maxime Llari ◽  
Yves Godio ◽  
Yves Jammes ◽  
...  
Keyword(s):  
Road Safety ◽  
Mechanical Response ◽  
Respiratory Mechanics ◽  
Numerical Models ◽  
Three Dimensional ◽  
Abdominal Pressure ◽  
Fe Model ◽  
Safety Research ◽  
Impact Biomechanics ◽  
Validation Parameters

Over the past decade, road safety research and impact biomechanics have strongly stimulated the development of anatomical human numerical models using the finite element (FE) approach. The good accuracy of these models, in terms of geometric definition and mechanical response, should now find new areas of application. We focus here on the use of such a model to investigate its potential when studying respiratory mechanics. The human body FE model used in this study was derived from the RADIOSS® HUMOS model. Modifications first concerned the integration and interfacing of a user-controlled respiratory muscular system including intercostal muscles, scalene muscles, the sternocleidomastoid muscle, and the diaphragm and abdominal wall muscles. Volumetric and pressure measurement procedures for the lungs and both the thoracic and abdominal chambers were also implemented. Validation of the respiratory module was assessed by comparing a simulated maximum inspiration maneuver to volunteer studies in the literature. Validation parameters included lung volume changes, rib rotations, diaphragm shape and vertical deflexion, and intra-abdominal pressure variation. The HUMOS model, initially dedicated to road safety research, could be turned into a promising, realistic 3D model of respiration with only minor modifications.

scholarly journals Tests on full-scale and static analysis models of the wood-framed building stucture horizontaly loaded

2017 ◽  
Vol 23 (6) ◽  
pp. 814-835 ◽  
Author(s):  
Jaroslaw MALESZA ◽  
Czeslaw MIEDZIALOWSKI ◽  
Leonas USTINOVICHIUS
Keyword(s):  
Numerical Models ◽  
Three Dimensional ◽  
Residential Building ◽  
Experimental Tests ◽  
High Energy ◽  
Experimental Investigations ◽  
Building Structure ◽  
Large Panel ◽  
Analysis Models ◽  
Structure Investigations

This paper focuses on development of the high energy saving timber building and ecological technology protecting environment in civil engineering. Wood framed with sheathing, large panel structures became more popular building constructions in Poland last decade. Experimental tests and numerical analysis of panels and complete wood framed building have been taken into account. Typical two-story residential building was selected for test. Test of three dimensional (3D) whole building was conducted on the base of experimental investigations results of large panel similar to those used in building structure. Also adequate tests of materials and connections were accompanying of the whole structure investigations. Obtained results were adopted in numerical models elaborated for wall and floor panels and in 3D model of whole building. Load -displacements characteristics were acquired from tests and numerical models. The displacements computed from 3D numerical model were 10–20% higher than from experiment. Experimentally ob-tained lower displacements than those from analytical analysis are resulted from higher stiffness of wall system due to diaphragms interconnections, their common interaction and three-dimensional character of building structure. Presented research analyzed method of computation of internal forces in building as well in the range of engineering methods in the form of rigid beam scheme up to the advanced methods using 3D spatial model adopting FEM.

Experimental and Numerical Investigations of HPC Blisks With a Focus on Travelling Waves

2010 ◽  
Author(s):  
Ulrik Strehlau ◽  
Arnold Ku¨hhorn
Keyword(s):  
Travelling Waves ◽  
Pressure Ratio ◽  
Integrated Design ◽  
Standing Waves ◽  
Travelling Wave ◽  
Experimental Investigations ◽  
Fe Model ◽  
Mode Localization ◽  
Numerical Investigations ◽  
Aero Engines

The motivation for the usage and a further development of blade integrated disk (blisk) technology is driven by a rising demand for efficient, economical and environment-friendly aero engines. In contrast to conventional bladed disks with separated blade and disk design, blisks are either manufactured from solid or disk and blades are assembled by friction welding. Due to an optimized stress distribution, the integrated design leads to potentially higher maximum rotational speeds of the HP-shaft and thus to an improved pressure ratio. This fact offers the opportunity to reduce the number of blades or even to save whole compressor stages. In order that a significant mass-reduction is achieved, which is increased since heavy blade-disk connections of the conventional design are not necessary anymore. Apart from the advantages of the integrated design, the vibration behaviour of a real blisk is more sophisticated compared to the conventional bladed disk design. Due to the very low mechanical damping, effects like mode-localization and amplitude magnification can lead to high cycle fatigue problems of such complex structures. Extensive experimental and numerical investigations are carried out considering a real rotor-stage 1 blisk of the Rolls-Royce E3E/1 demonstrator-HPC. In order to identify “blade individual frequencies” and “blade individual damping”- values, a new patented blade by blade measurement method is used, that provides FRFs characterized by an unique resonance, as known from SDOF-systems. Based on the adjusted FE-model, numerical and experimental investigations of the vibration behaviour in the frequency range of splitted double eigenvalues are carried out. In doing so the expressions “travelling wave” and “standing waves” are commonly used to characterize the eigenmodes and forced modes of vibration respectively. The splitting of eigenvalues could be proved and a novel criterion to distinguish travelling and standing waves is introduced.

Bottom End-Closure Design Optimization of DOT-39 Non-Refillable Refrigerant Cylinders

2005 ◽  
Vol 127 (2) ◽  
pp. 112-118 ◽  
Author(s):  
Y. Kisioglu ◽  
J. R. Brevick ◽  
G. L. Kinzel
Keyword(s):  
Finite Element Analysis ◽  
Volume Expansion ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Experimental Investigations ◽  
Element Analysis ◽  
Numerical Investigations ◽  
Pressure Tests ◽  
Experiment Technique ◽  
Static Conditions

This study addresses the problem of stability (standing of cylinders upright) of DOT-39 nonrefillable refrigerant cylinders using both experimental and finite element analysis (FEA) approaches. When these cylinders are designed using traditional methods they often suffer permanent volume expansion at the bottom end closure and become unstable when they are pressure tested experimentally. In this study, experimental investigations were carried out using hydrostatic pressure tests with water. In the case of numerical investigations, FEA models were developed for three-dimensional (3D) axisymmetric quasi-static conditions. The FEA models were constructed using nonhomogenous material nonlinearity and geometrical nonuniformity conditions. The results obtained from both FEA models and experimental tests were compared. To eliminate the instability of these cylinders, a design of experiment technique was employed to optimize the bottom end-closure design using the FEA models.

Numerical and Experimental Investigations of Cavitating Flow in a Vertical Multi-Hole Injector Nozzle

2010 ◽  
Author(s):  
Zhixia He ◽  
Jing Bai ◽  
Qian Wang ◽  
Qingmu Mu ◽  
Yunlong Huang
Keyword(s):  
Numerical Simulation ◽  
Numerical Models ◽  
Three Dimensional ◽  
Injection Pressure ◽  
Cavitating Flow ◽  
Critical Conditions ◽  
Experimental Investigations ◽  
Nozzle Flow ◽  
Cavitation Inception ◽  
Injector Nozzle

The presence of cavitation and turbulence in a diesel injector nozzle has significant effect on the subsequent spray characteristics. However, the mechanism of the cavitating flow and its effect on the subsequent spray is unclear because of the complexities of the nozzle flow, such as the cavitation phenomena and turbulence. A flow visualization experiment system with a transparent scaled-up vertical multi-hole injector nozzle tip was setup for getting the experimental data to make a comparison to validate the calculated results from the three dimensional numerical simulation of cavitating flow in the nozzle with mixture multi-phase cavitating flow model and good qualitative agreement was seen between the two sets of data. The critical conditions for cavitation inception were derived as well as the relationship between the discharge coefficient and non-dimensional cavitation parameter. After wards, the testified numerical models were used to analyze the effects of injection pressure, back pressure, cavitation parameter, Reynolds number, injector needle lift and needle eccentricity on the cavitating flow inside the nozzle. Combined with visual experimental results, numerical simulation results can clearly reveal the three-dimensional nature of the nozzle flow and the location and shape of the cavitation induced vapor distribution, which can help understand the nozzle flow better and eventually put forward the optimization ideas of diesel injectors.

An Investigation of the Bisymmetric Hydrostatic Collapse of Flexible Pipes Based on Equivalent Layer Approaches

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
José Renato M. de Sousa ◽  
Marcelo K. Protasio ◽  
Luís Volnei S. Sagrilo ◽  
Djalene Maria Rocha
Keyword(s):  
Numerical Models ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Collapse Mechanism ◽  
Fe Model ◽  
Flexible Pipe ◽  
Flexible Pipes ◽  
Dimensional Finite Element ◽  
Equivalent Ring ◽  
Three Dimensional Finite Element

Abstract The hydrostatic collapse strength of a flexible pipe is largely dependent on the ability of its carcass and/or pressure armor to resist radial loading and, therefore, its prediction involves an adequate modeling of these layers. Hence, initially, this work proposes a set of equations to estimate equivalent mechanical properties for these layers, which allows their modeling as equivalent orthotropic cylinders. Particularly, equations to predict the equivalent ring bend stiffness are obtained by simulating several two-point static ring tests with a three-dimensional finite element (FE) model based on beam elements and using these results to form datasets that are analyzed with a symbolic regression (SR) tool. The results of these analyses are the closed-form equations that best fit the provided datasets. After that, these equations are used in conjunction with a three-dimensional shell FE model (FEM) and a previously presented analytical model to study the bisymmetric hydrostatic collapse mechanism of flexible pipes. The predictions of these models agreed well with the collapse pressures obtained with numerical models and in experimental tests thus indicating the potential use of this approach in the design of flexible pipes.

Probability of Occurrence of Extreme Waves in Three Dimensional Mechanically Generated Random Wave Fields: A Comparison With Numerical Simulations

2011 ◽  
Author(s):  
A. Toffoli ◽  
S. Chai ◽  
E. M. Bitner-Gregersen ◽  
F. Pistani
Keyword(s):  
Numerical Simulations ◽  
Quantitative Estimate ◽  
Numerical Models ◽  
Modulational Instability ◽  
Three Dimensional ◽  
Random Wave ◽  
Extreme Waves ◽  
Wave Fields ◽  
Numerical Investigations ◽  
Probability Of Occurrence

Experimental and numerical investigations reveal that nonlinear modulational instability can significantly affect the probability of occurrence of extreme waves, especially if waves are sufficiently steep and narrow banded both in the frequency and directional domain. However, it is not yet completely clear whether numerical simulations can provide an accurate quantitative estimate of experimental results. Here the potential Euler equations are used to assess the ability of numerical models to describe the evolution of statistical properties of mechanically generated directional, random wave fields and in particular the evolution of the kurtosis. Results show that simulations provide a good quantitative estimate of experimental observations within a broad range of wave directional width.

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