Physics-Based Ejector Force Model

Das Forschungsprojekt „Prozessintegrierte Softsensorik zur Oberflächenkonditionierung beim Außenlängsdrehen von 42CrMo4“ widmet sich der Entstehung und der In-process-Erfassung von industriell relevanten Randschichtzuständen. Im Speziellen werden sogenannte White Layer und Eigenspannungszustände untersucht. Durch die modulare Verknüpfung von zerstörungsfreier Prüftechnik, Simulationsergebnissen und Prozesswissen mittels Datenfusion wird ein Softsensor erforscht. Dieser soll im Rahmen einer adaptiven Regelung des Drehprozesses eingesetzt werden und eine gezielte Einstellung von vorteilhaften Randschichtzuständen erlauben. The research project „Process-integrated soft sensor technology for surface conditioning during external longitudinal turning of 42CrMo4“ is dedicated to the formation and in-process-detection of surface layers with industrial relevance. In particular, so-called white layers and residual stresses are investigated. A soft sensor is being researched through the modular combination of non-destructive testing technology and process knowledge by means of data fusion. This is to be used in the context of an adaptive control of the turning process in order to adjust beneficial surface states.

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A re-examination of the role of friction in the original Social Force Model

Safety Science ◽

10.1016/j.ssci.2019.08.041 ◽

2020 ◽

Vol 121 ◽

pp. 42-53 ◽

Cited By ~ 2

Author(s):

I.M. Sticco ◽

G.A. Frank ◽

F.E. Cornes ◽

C.O. Dorso

Keyword(s):

Force Model ◽

Social Force ◽

Social Force Model

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Enhanced discrete phase model for multiphase flow simulation of blood flow with high shear stress

Science Progress ◽

10.1177/00368504211008064 ◽

2021 ◽

Vol 104 (1) ◽

pp. 003685042110080

Author(s):

Zheqin Yu ◽

Jianping Tan ◽

Shuai Wang

Keyword(s):

Blood Flow ◽

Shear Stress ◽

Multiphase Flow ◽

Experimental Verification ◽

Flow Simulation ◽

Turbulence Models ◽

Phase Model ◽

Force Model ◽

Discrete Phase Model ◽

Discrete Phase

Shear stress is often present in the blood flow within blood-contacting devices, which is the leading cause of hemolysis. However, the simulation method for blood flow with shear stress is still not perfect, especially the multiphase flow model and experimental verification. In this regard, this study proposes an enhanced discrete phase model for multiphase flow simulation of blood flow with shear stress. This simulation is based on the discrete phase model (DPM). According to the multiphase flow characteristics of blood, a virtual mass force model and a pressure gradient influence model are added to the calculation of cell particle motion. In the experimental verification, nozzle models were designed to simulate the flow with shear stress, varying the degree of shear stress through different nozzle sizes. The microscopic flow was measured by the Particle Image Velocimetry (PIV) experimental method. The comparison of the turbulence models and the verification of the simulation accuracy were carried out based on the experimental results. The result demonstrates that the simulation effect of the SST k- ω model is better than other standard turbulence models. Accuracy analysis proves that the simulation results are accurate and can capture the movement of cell-level particles in the flow with shear stress. The results of the research are conducive to obtaining accurate and comprehensive analysis results in the equipment development phase.

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A novel model of Z-pin insertion in prepreg based on fracture mechanics

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/09544054211014442 ◽

2021 ◽

pp. 095440542110144

Author(s):

Guobiao Ji ◽

Liang Cheng ◽

Shaohua Fei ◽

Jiangxiong Li ◽

Yinglin Ke

Keyword(s):

Fracture Toughness ◽

Fracture Mechanics ◽

Analytical Model ◽

Model Parameters ◽

Force Model ◽

Fe Model ◽

Cohesive Elements ◽

Fe Method ◽

Insertion Force ◽

Mechanics Model

Through-thickness reinforcement is a promising solution to the problem of delamination susceptibility in laminated composites. Modeling Z-pin–prepreg interaction is essential for accurate robotics-assisted Z-pin insertion. In this paper, a novel Z-pin insertion force model combining the classical cohesive finite element (FE) method with a dynamic analytical fracture mechanics model is proposed. The velocity-dependent cohesive elements, in which the fracture toughness is provided by the analytical model, are implemented in Z-pin insertion FE model to predict the crack initiation and propagation. Then Z-pin insertion experiments are performed on prepreg sample with metallic Z-pins at different velocities to identify the analytical model parameters and validate the simulation predictions offered by the model. Dynamics of Z-pin interaction with inhomogeneous prepreg is described and the effects of insertion velocity on prepreg contact force are studied. Results show that the force model agrees well with experiments and the fracture toughness rises with the increasing Z-pin insertion velocity.

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Optimum Design for the Frame of Open Type Abrasive Flow Polish Machine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.497.89 ◽

2012 ◽

Vol 497 ◽

pp. 89-93

Author(s):

Liang Liang Yuan ◽

Ke Hua Zhang ◽

Li Min

Keyword(s):

Finite Element ◽

Natural Frequency ◽

Finite Element Methods ◽

Optimization Design ◽

Low Cost ◽

Three Dimensional ◽

Force Model ◽

Optimization Analysis ◽

Open Type ◽

Set Up

In order to process heterotype hole of workpiece precisely, an open abrasive flow polish machine is designed, and the optimization design of machine frame is done for low cost. Firstly, basing on the parameters designed with traditional ways, three-dimensional force model is set up with the soft of SolidWorks. Secondly, the statics and modal analysis for machine body have been done in Finite element methods (FEM), and then the optimization analysis of machine frame has been done. At last, the model of rebuild machine frame has been built. Result shows that the deformation angle value of machine frame increased from 0.72′ to 1.001′, the natural frequency of the machine decreased from 75.549 Hz to 62.262 Hz, the weight of machine decreased by 74.178 Kg after optimization. It meets the strength, stiffness and angel stiffness requirement of machine, reduces the weight and cost of machine.

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Crowd Evacuation Guidance Based on Combined Action Reinforcement Learning

Algorithms ◽

10.3390/a14010026 ◽

2021 ◽

Vol 14 (1) ◽

pp. 26

Author(s):

Yiran Xue ◽

Rui Wu ◽

Jiafeng Liu ◽

Xianglong Tang

Keyword(s):

Reinforcement Learning ◽

Guidance System ◽

Force Model ◽

Interactive Simulation ◽

Social Force ◽

Novel Approach ◽

Learning Agent ◽

Network Output ◽

Combined Action ◽

Crowd Evacuation

Existing crowd evacuation guidance systems require the manual design of models and input parameters, incurring a significant workload and a potential for errors. This paper proposed an end-to-end intelligent evacuation guidance method based on deep reinforcement learning, and designed an interactive simulation environment based on the social force model. The agent could automatically learn a scene model and path planning strategy with only scene images as input, and directly output dynamic signage information. Aiming to solve the “dimension disaster” phenomenon of the deep Q network (DQN) algorithm in crowd evacuation, this paper proposed a combined action-space DQN (CA-DQN) algorithm that grouped Q network output layer nodes according to action dimensions, which significantly reduced the network complexity and improved system practicality in complex scenes. In this paper, the evacuation guidance system is defined as a reinforcement learning agent and implemented by the CA-DQN method, which provides a novel approach for the evacuation guidance problem. The experiments demonstrate that the proposed method is superior to the static guidance method, and on par with the manually designed model method.

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