scholarly journals Study on the Effect of Geometrical Parameters of a Hexagonal Trigger on Energy Absorber Performance Using ANN

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5981
Author(s):  
Michał Rogala ◽  
Jakub Gajewski ◽  
Marcin Górecki
Keyword(s):  
High Speed ◽  
Time Lapse ◽  
Numerical Analyses ◽  
Motor Vehicles ◽  
Geometrical Parameters ◽  
Total Efficiency ◽  
Energy Absorber ◽  
Thin Walled Structures ◽  
Post Buckling ◽  
Energy Absorbers

Thin-walled structures are commonly used as energy absorbers in motor vehicles. Their function is to protect the structural components of vehicles and to absorb energy completely during collisions up to 20 km/h. This paper focuses on maintaining crush axiality during research. To verify the numerical analyses, physical specimens were made and then subjected to dynamic crushing. Force and shortening values as well as high-speed camera images were used for data analysis. Through time-lapse shots, plastic deformation within the crush initiator was observed. Such detailed analysis allowed the determination of the influence of hexagonal triggers in the form of notches on the post-buckling progressive analysis. In this paper, neural networks were used to examine the importance of each variable. Data from numerical analyses were used for this purpose. Based on the analyses performed, the effects of both the width and height of the triggers on the crush load efficiency (CLE) and total efficiency (TE) ratios can be seen. The width of the crush initiator has the greatest influence on Crash-box performance. Nevertheless, increasing both the height and the width of the initiator can result in crush non-axiality and underperformance of the energy absorber.

Impact Response of Thin-Walled Tubes: A Prospective Review

2012 ◽  
Vol 165 ◽  
pp. 130-134 ◽  
Author(s):  
Fauziah Mat ◽  
K. Azwan Ismail ◽  
S. Yaacob ◽  
O. Inayatullah
Keyword(s):  
Compressive Loading ◽  
Axial Loading ◽  
Geometrical Parameters ◽  
Axial Deformation ◽  
Thin Walled Structures ◽  
Structural Applications ◽  
Thin Walled ◽  
Energy Absorbers ◽  
Energy Absorbing ◽  
The Impact

Thin-walled structures have been widely used in various structural applications asimpact energy absorbing devices. During an impact situation, thin-walled tubesdemonstrate excellent capability in absorbing greater energy through plastic deformation. In this paper, a review of thin-walled tubes as collapsible energy absorbers is presented.As a mean of improving the impact energy absorption of thin-walled tubes, the influence of geometrical parameters such as length, diameter and wall thickness on the response of thin-walled tubes under compression axial loading are briefly discussed. Several design improvements proposed by previous researchers are also presented. The scope of this review is mainly focus on axial deformation under quasi-static and dynamic compressive loading. Other deformations, such as lateral indentation, inversion and splitting are considered beyond the scope of this paper. This review is intended to assist the future development of thin-walled tubes as efficient energy absorbing elements.

Crashworthiness Optimization of a Vertex Fractal Hexagonal Structure

2019 ◽  
Vol 17 (07) ◽  
pp. 1950031 ◽  
Author(s):  
Yong Zhang ◽  
Ning He ◽  
Yubo Hou
Keyword(s):  
Numerical Modeling ◽  
Design Optimization ◽  
Automotive Industry ◽  
Experimental Analysis ◽  
Hexagonal Structure ◽  
Geometrical Parameters ◽  
Energy Absorber ◽  
Crashworthiness Optimization ◽  
Thin Walled Structures ◽  
Thin Walled

Thin-walled structures are used in automotive industry due to their excellent lightweight and crashworthiness properties. This paper proposes a vertex fractal multi-cell hexagonal structure to develop a novel lightweight energy absorber. Experimental analysis and numerical modeling are performed to investigate the crashworthiness of the fractal multi-cell hexagonal structures. The numerical results indicate that fractal configurations and geometrical parameters of the fractal hexagonal structure have significant effect on the crashworthiness. In addition, the multi-objective design optimization is performed to seek the optimal crashworthiness parameters and explore the optimal crashworthiness of the fractal hexagonal structure. The results show that the fractal multi-cell hexagonal structure outperforms non-fractal hexagonal structure.

Five-Dimensional Microscopy using Widefield-Deconvolution: Practical Considerations and Biological Applications

1996 ◽  
Vol 54 ◽  
pp. 268-269
Author(s):  
W.F. Marshall ◽  
K. Oegema ◽  
J. Nunnari ◽  
A.F. Straight ◽  
D.A. Agard ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
High Speed ◽  
Laser Scanning ◽  
Ccd Camera ◽  
Image Plane ◽  
Time Lapse ◽  
Laser Scanning Confocal Microscopy ◽  
Three Dimensions ◽  
Excitation Light ◽  
Cooled Ccd

The ability to image cells in three dimensions has brought about a revolution in biological microscopy, enabling many questions to be asked which would be inaccessible without this capability. There are currently two major methods of three dimensional microscopy: laser-scanning confocal microscopy and widefield-deconvolution microscopy. The method of widefield-deconvolution uses a cooled CCD to acquire images from a standard widefield microscope, and then computationally removes out of focus blur. Using such a scheme, it is easy to acquire time-lapse 3D images of living cells without killing them, and to do so for multiple wavelengths (using computer-controlled filter wheels). Thus, it is now not only feasible, but routine, to perform five dimensional microscopy (three spatial dimensions, plus time, plus wavelength).Widefield-deconvolution has several advantages over confocal microscopy. The two main advantages are high speed of acquisition (because there is no scanning, a single optical section is acquired at a time by using a cooled CCD camera) and the use of low excitation light levels Excitation intensity can be much lower than in a confocal microscope for three reasons: 1) longer exposures can be taken since the entire 512x512 image plane is acquired in parallel, so that dwell time is not an issue, 2) the higher quantum efficiently of a CCD detect over those typically used in confocal microscopy (although this is expected to change due to advances in confocal detector technology), and 3) because no pinhole is used to reject light, a much larger fraction of the emitted light is collected. Thus we can typically acquire images with thousands of photons per pixel using a mercury lamp, instead of a laser, for illumination. The use of low excitation light is critical for living samples, and also reduces bleaching. The high speed of widefield microscopy is also essential for time-lapse 3D microscopy, since one must acquire images quickly enough to resolve interesting events.

scholarly journals Module to Support Real-Time Microscopic Imaging of Living Organisms on Ground-Based Microgravity Analogs

2021 ◽  
Vol 11 (7) ◽  
pp. 3122
Author(s):  
Srujana Neelam ◽  
Audrey Lee ◽  
Michael A. Lane ◽  
Ceasar Udave ◽  
Howard G. Levine ◽  
...  
Keyword(s):  
Real Time ◽  
High Speed ◽  
Simulated Microgravity ◽  
Image Acquisition ◽  
Time Lapse ◽  
Moving Frames ◽  
Cell Functions ◽  
Microgravity Simulation ◽  
Division Cell ◽  
Over Time

Since opportunities for spaceflight experiments are scarce, ground-based microgravity simulation devices (MSDs) offer accessible and economical alternatives for gravitational biology studies. Among the MSDs, the random positioning machine (RPM) provides simulated microgravity conditions on the ground by randomizing rotating biological samples in two axes to distribute the Earth’s gravity vector in all directions over time. Real-time microscopy and image acquisition during microgravity simulation are of particular interest to enable the study of how basic cell functions, such as division, migration, and proliferation, progress under altered gravity conditions. However, these capabilities have been difficult to implement due to the constantly moving frames of the RPM as well as mechanical noise. Therefore, we developed an image acquisition module that can be mounted on an RPM to capture live images over time while the specimen is in the simulated microgravity (SMG) environment. This module integrates a digital microscope with a magnification range of 20× to 700×, a high-speed data transmission adaptor for the wireless streaming of time-lapse images, and a backlight illuminator to view the sample under brightfield and darkfield modes. With this module, we successfully demonstrated the real-time imaging of human cells cultured on an RPM in brightfield, lasting up to 80 h, and also visualized them in green fluorescent channel. This module was successful in monitoring cell morphology and in quantifying the rate of cell division, cell migration, and wound healing in SMG. It can be easily modified to study the response of other biological specimens to SMG.

Research on Mode of after-Sale Reverse Logistics Operation of Auto Maintenance Industry Based on Time Window

2011 ◽  
Vol 121-126 ◽  
pp. 4635-4639
Author(s):  
Hao Hao ◽  
Xing Gen Wu ◽  
Hong Yu Li
Keyword(s):  
Supply Chain ◽  
Reverse Logistics ◽  
High Speed ◽  
Time Window ◽  
Auto Industry ◽  
Road Transport ◽  
Motor Vehicles ◽  
Safety Testing ◽  
Internal Operations ◽  
Evaluation Mechanism

The author maintains that, with the quick development of domestic auto industry, the auto maintenance industry is progressing with high speed accordingly. The auto maintenance enterprise are inclined to focus on sales and forward supply chain operation, however, lacking of efficient resource and systematic management into reverse logistics operation, as lead to a few potential risks. In order to avoid and control the risks, the auto maintenance companies need to closely cooperate with channel supply chain partners, meanwhile build up the mode of reverse logistics operation with timing efficiency orientation. This mode consists of eight sub-system modules: organization structure, network planning and layout, reverse logistics operation procedure, time window evaluation mechanism, automatic replenishment system, reverse forecasting system, Kan-ban message system as well as disposal & reuse system. Furthermore, the article makes analysis of the internal operations and external relevance of these eight sub-systems. In recent years, with the overall opening up of road transport market and the rapid growth in domestic economy, the total number of China’s motor vehicles is entering a high-speed growth channel, and “the car goes to the country” policy further promotes the auto industry. Under the situation of quick development, the auto maintenance industry is developing by 10% to 15% each year as a young profession. According to the statistics, there are over 380,000 auto maintenance enterprises in our country at the moment, and various types of auto safety testing stations are built around one after another. The intense competition among auto maintenance manufacturing enterprises does not only focus on product quality, but also on the after-market reverse logistics. According to the statics of Gartner, 70 percent of resale is related with sales service, and 60 percent of resale is related with after market. However, except for few leading business enterprises which have realized the direct influence and value contribution of after-service reverse logistics to profit increase and customer loyalty and take action to pioneer the profit territory in the after-sale reverse logistics, the ‘price war’ is still the main competition method which the majority of enterprises adopt in the market.

scholarly journals Large deflection and post-buckling of thin-walled structures by finite elements with node-dependent kinematics

2020 ◽  
Author(s):  
E. Carrera ◽  
◽  
A. Pagani ◽  
R. Augello
Keyword(s):  
Finite Elements ◽  
Large Deflection ◽  
Nonlinear Problems ◽  
Structural Domain ◽  
Fe Model ◽  
Efficient Manner ◽  
Cross Sectional ◽  
Thin Walled Structures ◽  
Post Buckling ◽  
Thin Walled

AbstractIn the framework of finite elements (FEs) applications, this paper proposes the use of the node-dependent kinematics (NDK) concept to the large deflection and post-buckling analysis of thin-walled metallic one-dimensional (1D) structures. Thin-walled structures could easily exhibit local phenomena which would require refinement of the kinematics in parts of them. This fact is particularly true whenever these thin structures undergo large deflection and post-buckling. FEs with kinematics uniform in each node could prove inappropriate or computationally expensive to solve these locally dependent deformations. The concept of NDK allows kinematics to be independent in each element node; therefore, the theory of structures changes continuously over the structural domain. NDK has been successfully applied to solve linear problems by the authors in previous works. It is herein extended to analyze in a computationally efficient manner nonlinear problems of beam-like structures. The unified 1D FE model in the framework of the Carrera Unified Formulation (CUF) is referred to. CUF allows introducing, at the node level, any theory/kinematics for the evaluation of the cross-sectional deformations of the thin-walled beam. A total Lagrangian formulation along with full Green–Lagrange strains and 2nd Piola Kirchhoff stresses are used. The resulting geometrical nonlinear equations are solved with the Newton–Raphson linearization and the arc-length type constraint. Thin-walled metallic structures are analyzed, with symmetric and asymmetric C-sections, subjected to transverse and compression loadings. Results show how FE models with NDK behave as well as their convenience with respect to the classical FE analysis with the same kinematics for the whole nodes. In particular, zones which undergo remarkable deformations demand high-order theories of structures, whereas a lower-order theory can be employed if no local phenomena occur: this is easily accomplished by NDK analysis. Remarkable advantages are shown in the analysis of thin-walled structures with transverse stiffeners.

An experimental investigation of incipient spilling breakers

2009 ◽  
Vol 633 ◽  
pp. 271-283 ◽  
Author(s):  
J. D. DIORIO ◽  
X. LIU ◽  
J. H. DUNCAN
Keyword(s):  
Wave Breaking ◽  
High Speed ◽  
Phase Speed ◽  
Breaking Waves ◽  
Front Face ◽  
Geometrical Parameters ◽  
Instability Mechanism ◽  
Scaling Relationships ◽  
Self Similar ◽  
Spilling Breakers

In the present paper, the profiles of incipient spilling breaking waves with wavelengths ranging from 10 to 120cm were studied experimentally in clean water. Short-wavelength breakers were generated by wind, while longer-wavelength breakers were generated by a mechanical wavemaker, using either a dispersive focusing or a sideband instability mechanism. The crest profiles of these waves were measured with a high-speed cinematic laser-induced fluorescence technique. For all the wave conditions reported herein, wave breaking was initiated with a capillary-ripple pattern as described in Duncan et al. (J. Fluid Mech., vol. 379, 1999, pp. 191–222). In the present paper, it is shown that at incipient breaking the crest shape is self-similar with two geometrical parameters that depend only on the slope of a particular point on the front face of the gravity wave. The scaling relationships appear to be universal for the range of wavelengths studied herein and hold for waves generated by mechanical wavemakers and by wind. The slope measure is found to be dependent on the wave phase speed and the rate of growth of the crest height prior to incipient breaking.

An Artificial Intelligence Based Method for Performance Prediction and Inverse Design of Hydraulic Turbochargers

2020 ◽  
Author(s):  
Azam Thatte ◽  
Ganesh Vurimi ◽  
Prabhav Borate ◽  
Teymour Javaherchi
Keyword(s):  
Neural Network ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Inverse Design ◽  
Geometrical Parameters ◽  
Total Efficiency ◽  
Design Algorithm ◽  
Flow Rates ◽  
Radial Turbine ◽  
Radial Pump

Abstract A neural network based method is developed that can learn the underlying physics of hydraulic turbocharger (a radial pump coupled with a radial turbine) from a set of sparse experimental data and can predict the performance of a new turbocharger design for any given set of previously unseen operating conditions and geometric parameters. The novelty of the algorithm is that it learns the underlying physical mechanisms from a very sparse data spanning a broad range of flow rates and geometrical size brackets and uses these deeper common features recognized through a “mass-learning process” to predict the full performance curves for any given single geometry. The deep learning algorithm is able to accurately predict the key performance parameters like total efficiency of the turbocharger, its operating speed, pressure rise provided by the radial pump of the turbocharger and the shaft power produced by the radial turbine of the turbocharger for any given input combination of pump and turbine flow rates, differential pressure across the turbine and a limited set of geometrical parameters of pump and turbine impellers and volutes. Lastly, a novel method for fast inverse design of turbomachinery using a physics trained neural network and a constrained optimization algorithms is developed. The algorithm uses Nelder-Mead and Interior Point methods to find the global minimum of turbocharger design objective function in multi-dimensional space. The newly developed method is found to be very efficient in optimizing turbomachinery design problems with both equality and inequality constraints. The inverse design algorithm is able to successfully recommend an optimal combination of geometrical parameters like pump blade exit angle, pump impeller diameter, blade width, eye diameter, turbine nozzle diameter and rotational speed for a given target efficiency and head rise requirements. The preliminary results from this study indicate that it has a great potential to minimize the need for expensive 3D CFD based methods for the design of turbomachinery.

scholarly journals Experimental research in automobile non-pneumatic tire force heterogeneity

2018 ◽  
Vol 224 ◽  
pp. 02019 ◽  
Author(s):  
Vladimir Mazur
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Efficiency ◽  
Motor Vehicle ◽  
Heavy Traffic ◽  
Polymeric Materials ◽  
Air Pressure ◽  
Motor Vehicles ◽  
Tire Force ◽  
Excess Air

Simplicity and high efficiency of a wheeled mover as a mechanism for converting rotational motion into a translatory one have conditioned its wide application in overland machines including motor vehicles. However a wheel with a non-pneumatic tyre (NPT) has a sufficient drawback lying in termination of a wheeled machine movement at the excess air pressure loss. Moreover, the loss of excess air pressure in a pneumatic tyre of traditional design at high speed of movement of a motor vehicle can lead to a traffic accident with heavy consequences. The stop of a motor vehicle to change a wheel on a heavy traffic roadway or roadside also poses a threat. These reasons determine the necessity of both well-known design improvements and search for the new wheeled mover design solutions to enhance a motor vehicle safety, the use of wheels with non-pneumatic tyres of elastic polymeric materials being one of them. Safety enhancement by means of non-pneumatic tyre use along with keeping the high performance of wheeled machine operational properties, is an important scientific and technical task that determines the research urgency.

Sign in / Sign up

Export Citation Format

Share Document