scholarly journals Evaluation of a novel approach for considering damping effects in a process force model of a geometric physically-based milling simulation

Procedia CIRP ◽  
2021 ◽  
Vol 103 ◽  
pp. 188-193
Author(s):  
Florian Wöste ◽  
Tobias Siebrecht ◽  
Petra Wiederkehr
Keyword(s):  
Force Model ◽  
Milling Simulation ◽  
Novel Approach ◽  
Physically Based ◽  
Damping Effects

scholarly journals Crowd Evacuation Guidance Based on Combined Action Reinforcement Learning

Algorithms ◽  
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.

Rigidity Regulation Approach for Geometric Tolerance Optimization in End Milling of Thin-walled Components

2021 ◽  
pp. 1-34
Author(s):  
Ankit Agarwal ◽  
K A Desai
Keyword(s):  
End Milling ◽  
Traditional Approach ◽  
Force Model ◽  
Geometric Tolerances ◽  
Novel Approach ◽  
Cutting Sequences ◽  
Finish Cutting ◽  
Thin Walled ◽  
Cutting Sequence ◽  
Regulation Approach

Abstract The paper presents a novel approach to improve geometric tolerances (flatness and cylindricity) by manipulating the rigidity among finishing and roughing cutting sequences during end milling of thin-walled components. The proposed approach considers the design configuration of the thin-walled component as an input and aims to determine semi-finished geometry such that the geometric tolerances are optimized while performing finish cutting sequence. The objective is accomplished by combining Mechanistic force model, Finite Element (FE) analysis based workpiece deflection model and Particle Swarm Optimization (PSO) technique to determine optimal disposition of material along the length of component thereby regulating rigidity. The algorithm has been validated by determining rigidity regulated semi-finished geometries for thin-walled components having straight, concave and convex configurations. The outcomes of the proposed algorithm are substantiated further by conducting a set of end milling experiments for each of these cases. The results of the proposed strategy are compared with a traditional approach considering no change in the rigidity of component along length of the cut. It is demonstrated that the proposed approach can effectively optimize geometric tolerances for thin-walled components during end milling operation.

Mechanistic Modeling of Process Damping in Peripheral Milling

2005 ◽  
Author(s):  
C. Y. Huang ◽  
J.-J. Junz Wang
Keyword(s):  
Cutting Speed ◽  
Vibration Signal ◽  
Mechanistic Modeling ◽  
Force Model ◽  
Total Force ◽  
Peripheral Milling ◽  
Process Damping ◽  
Damping Effect ◽  
Damping Effects ◽  
Cutting Mechanisms

This paper extends analytical modeling of the milling process to include process damping effects. Two cutting mechanisms (shearing and plowing mechanisms) and two process damping effects (directional and magnitude effects) are included. The directional effect is related to vibration energy dissipation due to directional variation of cutter/workpiece relative motion. The magnitude effect is associated with change in force magnitude due to variation of rake angle and clearance angle. Process damping is summarized as containing these separate components; direction-shearing, direction-plowing, magnitude-shearing and magnitude-plowing. The total force model including the process damping effect is obtained through convolution integration of the local forces. The analytical nature of this model makes it possible to determine unknown process damping coefficients from measured vibration signal during milling. The effects of cutting conditions (cutting speed, feed, axial and radial depths of cut) on process damping are systematically examined. It is shown that total process damping increases with increasing feed, axial and radial depths of cut, but decreases with increasing cutting velocity. Predictions based on the analytical model are verified by experiment. Results show that plowing mechanism contributes more to the total damping effect than the shearing mechanism, and magnitude-plowing effect has by far the greatest influence on total damping.

GRACE-FO accelerometer data recovery within ITSG-Grace2018 data processing

2020 ◽  
Author(s):  
Saniya Behzadpour ◽  
Torsten Mayer-Gürr ◽  
Andreas Kvas ◽  
Sandro Krauss ◽  
Sebastian Strasser ◽  
...  
Keyword(s):  
Gravitational Force ◽  
State Of The Art ◽  
Data Recovery ◽  
Force Model ◽  
Accelerometer Data ◽  
New Approach ◽  
Gravitational Forces ◽  
Gravity Field Recovery ◽  
Novel Approach ◽  
Gravity Recovery

<p>In GRACE-FO (Gravity Recovery and Climate Experiment Follow-on) mission, similar to its predecessor GRACE, the twin satellites are equipped with three-axis accelerometers, measuring the non-gravitational forces. After one month in orbit, the GRACE-D accelerometer data degraded and its measurements were replaced by synthetic accelerometer data, the so-called transplant data, officially generated by the Jet Propulsion Laboratory (JPL). The transplant data was derived from the GRACE-C accelerometer measurements, by applying a time and attitude corrections and adding model-based residual accelerations due to thruster firings on GRACE-D.</p><p>For the ITSG-Grace2018 GRACE-FO release, the gravity field recovery is based on the use of in-house Level-1B accelerometer data (ACT1B) using the provided Level-1A data products. In this work, we present a novel approach to recover the ACT1B data by (a) implementing the state-of-the-art non-gravitational force models and (b) applying additional force model corrections.</p><p>The preliminary results show the improved ACT1B data not only contributed to a noise reduction but also improved the estimates of the C20 and C30 coefficients. We show that the offset between SLR (Satellite Laser Ranging) and GRACE-FO derived C20 and C30 time series can be reduced remarkably by the use of the new accelerometer product, demonstrating the merit of this new approach.</p>

Seasonal erosion patterns under alpine conditions: benefits and challenges of a novel approach in physically based soil erosion modeling

2016 ◽  
Vol 60 (1) ◽  
pp. 109-123 ◽  
Author(s):  
Marcus Schindewolf ◽  
Andreas Kaiser ◽  
Fabian Neugirg ◽  
Constanze Richter ◽  
Florian Haas ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Erosion Modeling ◽  
Soil Erosion Modeling ◽  
Novel Approach ◽  
Physically Based

Novel Approach to Model Static Recrystallization of Austenite during Hot-Rolling of Nb-Microalloyed Steel: Effect of Precipitates

2013 ◽  
Vol 753 ◽  
pp. 417-422 ◽  
Author(s):  
Kashif Rehman ◽  
Hatem S. Zurob
Keyword(s):  
Size Control ◽  
Quantitative Agreement ◽  
Valuable Insight ◽  
Physically Based Model ◽  
Novel Approach ◽  
Model Predictions ◽  
Physically Based ◽  
Grain Size Control ◽  
Nb Microalloyed Steel ◽  
Insight Into

Microalloying additions are critical for grain size control during thermo-mechanical processing. The addition of niobium is known to delay the onset and growth of recrystallization. A physically-based model for the interaction of strain-induced precipitation, recovery and recrystallization is presented. A key feature of the model is the incorporation of the effect of precipitation on the nucleation of recrystallization. Quantitative agreement between the experimental measurements and the model predictions has also been demonstrated. The model offers valuable insight into the relative contributions of solute and precipitate Nb as well as the optimum conditions for strain accumulation.

scholarly journals The Risk of Obsolescence: Reframing the Contemporary Use of Force Model to Achieve a More Holistic Application of the UN Charter Jus Ad Bellum Construct

2021 ◽  
pp. 1-68
Author(s):  
BRIAN L. COX
Keyword(s):  
United Nations ◽  
Armed Conflict ◽  
Use Of Force ◽  
Force Model ◽  
Jus Ad Bellum ◽  
Novel Approach ◽  
The United Nations ◽  
Selection Of

Abstract This article challenges the effectiveness of the prevailing interpretation of the contemporary use of force model that is centred on a decidedly narrow selection of relevant provisions of the Charter of the United Nations (UN Charter). In the now seventy-five years of the UN Charter era, predominant modes of armed conflict have evolved so as to be largely unrecognizable when compared to the model of war that was contemplated when negotiating and ratifying the Charter. Nonetheless, modes of engaging with an actual or contemplated use of force remain rooted in a model developed more than seven decades ago. This article suggests that a new frame of analysis is needed. The “Reframer” approach and “Purposes and Principles” model developed herein remain just as firmly grounded in the UN Charter as the prevailing interpretation. However, this novel approach and model incorporate a degree of nuance and adaptiveness that is not feasible when applying the prevailing interpretation of the contemporary use of force model.

The Identification of Radial Runout in Milling Operations

1999 ◽  
Vol 121 (3) ◽  
pp. 524-531 ◽  
Author(s):  
R. J. Seethaler ◽  
I. Yellowley
Keyword(s):  
Experimental Evidence ◽  
Force Model ◽  
Novel Approach ◽  
Milling Operations ◽  
Wide Range ◽  
Linear Force ◽  
Force Components

The authors discuss a novel approach to estimation of individual tooth runout in milling. The approach is based upon a simplified linear force model and leads to good results at high values of immersion. Two variants of the approach for estimating runout are presented. The first method utilizes torque while the second considers in plane force components as indicators of runout. Simulations are used to verify the equations that were derived for relating runout to in plane forces and to allow the assessment of the influence of the spacing of the discrete force samples on accuracy. Experimental evidence validates the approach for a wide range of immersion values. Experiments also show that the approach is able to identify edge breakage in the presence of significant initial runout.

scholarly journals Combining geostatistics and physically-based simulations to characterize contaminated soils

2020 ◽  
Author(s):  
Mathieu Le Coz ◽  
Léa Pannecoucke ◽  
Xavier Freulon ◽  
Charlotte Cazala ◽  
Chantal de Fouquet
Keyword(s):  
Contaminated Soils ◽  
Absolute Error ◽  
Numerical Code ◽  
Test Case ◽  
Industrial Sites ◽  
Complex Processes ◽  
Novel Approach ◽  
Geostatistical Estimation ◽  
Physically Based ◽  
Geological Units

<p>Characterization of contamination in soils resulting from nuclear or industrial activities is a crucial issue for site remediation. A classical approach consists in delineating the contaminated zones based on a geostatistical estimation calibrated from measured activities, but it results in high uncertainties when the number of measurements is low and/or the spatial variability of the studied variable is governed by complex processes. In order to reduce these uncertainties, a novel approach, called Kriging with Numerical Variogram (KNV), is developed: the variogram is computed from a set of physically-based flow-and-transport simulations rather than from the measurements.</p><p>The KNV approach is assessed on a two-dimensional synthetic reference test case reproducing the migration of a tritium plume within an unsaturated soil with hydraulic properties highly variable in space. The results show that the mean absolute error in estimated activities is 50% to 75% lower with KNV compared to classical geostatistical approaches, depending on the sampling scenario. Moreover, KNV leads to a significant reduction of the empirical error standard deviation, which reflects uncertainties on the estimated activities. The performance of KNV regarding the classification into contaminated or not-contaminated zones is yet sensitive to the contamination threshold.</p><p>The KNV approach could thus help to better estimate volumes of soils to be decontaminated in the context of remediation of nuclear or industrial sites. This approach can be transposed to other scales of heterogeneities, such as systems with several geological units, or other pollutants with a more complex chemical behavior, as soon as a numerical code that simulates the phenomenon under study is available.</p><p><em>This study is part of Kri-Terres project, supported by the French National Radioactive Waste Management Agency (Andra) under the “Investments for the Future” national program.</em></p>

Sign in / Sign up

Export Citation Format

Share Document