scholarly journals Modelling and Simulation on Penetration into Stone Concrete

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
He Huang ◽  
Duo Zhang ◽  
Lirong Cheng
Keyword(s):  
Numerical Model ◽  
Damage Model ◽  
Research Area ◽  
Fast Calculation ◽  
Plastic Damage ◽  
Resistance Model ◽  
Important Research Area ◽  
Complete Theories ◽  
Stone Concrete ◽  
Concrete Target

Penetration into stone concrete is an important research area of concrete penetration, and related experiments and simulation tests have been carried out. However, complete theories have not been formed yet. This paper develops a differential facet resistance model for penetration into stone concrete target. Firstly, the plastic damage model is used to analyze the penetration of concrete target, and the reliability of the numerical model is verified by comparing with the classical experimental results. Besides, the numerical model of stone concrete is established based on 3D Voronoi diagram according to the random characteristics of the shape and spatial distribution of stones in concrete. Then, simulation tests are carried out with the validated numerical model, a differential facet resistance model suitable for the penetration of stone concrete target is then proposed referring to the resistance formula of Forrestal and Rosenberg. At last, a method for fast calculation of penetration into stone concrete is introduced.

scholarly journals A tool wear condition monitoring approach for end milling based on numerical simulation

2021 ◽  
Vol 23 (2) ◽  
pp. 371-380
Author(s):  
Qinsong Zhu ◽  
Weifang Sun ◽  
Yuqing Zhou ◽  
Chen Gao
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Tool Wear ◽  
Condition Monitoring ◽  
End Milling ◽  
Orthogonal Experiment ◽  
Research Area ◽  
Model Parameters ◽  
Evaluation Indexes ◽  
Important Research Area

As an important research area of modern manufacturing, tool condition monitoring (TCM) has attracted much attention, especially artificial intelligence (AI)- based TCM method. However, the training samples obtained in practical experiments have the problem of sample missing and sample insufficiency. A numerical simulation- based TCM method is proposed to solve the above problem. First, a numerical model based on Johnson-Cook model is established, and the model parameters are optimized through orthogonal experiment technology, in which the KL divergence and cosine similarity are used as the evaluation indexes. Second, samples under various tool wear categories are obtained by the optimized numerical model above to provide missing samples not present in the practical experiments and expand sample size. The effectiveness of the proposed method is verified by its application in end milling TCM experiments. The results indicate the classification accuracies of four classifiers (SVM, RF, DT, and GRNN) can be improved significantly by the proposed TCM method.

Research Commentary: Analysis of Curriculum Standards: An Important Research Area

2016 ◽  
Vol 47 (2) ◽  
pp. 118-133 ◽  
Author(s):  
Dung Tran ◽  
Barbara J. Reys ◽  
Dawn Teuscher ◽  
Shannon Dingman ◽  
Lisa Kasmer
Keyword(s):  
Mathematics Education ◽  
Education Reform ◽  
Careful Analysis ◽  
Research Area ◽  
State Standards ◽  
Content Standards ◽  
Curriculum Standards ◽  
Education Professionals ◽  
Important Research Area ◽  
Improving Student Learning

This commentary highlights the contribution that careful and systematic analyses of curriculum or content standards can make to questions and issues important in the mathematics education field. We note the increased role that curriculum standards have played as part of a standards-based education reform strategy. We also review different methods used by researchers to compare and analyze the Common Core State Standards for Mathematics, each method designed for a particular purpose. Finally, we call upon mathematics education researchers to engage in careful analysis of curriculum standards and to share their findings in ways that can inform public debate as well as support education professionals in improving student learning opportunities.

Cross-Ply Laminates under Static Three-Point Bending: A Numerical Development Model

2012 ◽  
Vol 498 ◽  
pp. 42-54 ◽  
Author(s):  
S. Benbelaid ◽  
B. Bezzazi ◽  
A. Bezazi
Keyword(s):  
Numerical Model ◽  
Damage Mechanics ◽  
Progressive Failure ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Failure Criteria ◽  
Continuum Damage ◽  
Damage Development ◽  
Element Analysis ◽  
Progressive Failure Analysis

This paper considers damage development mechanisms in cross-ply laminates using an accurate numerical model. Under static three points bending, two modes of damage progression in cross-ply laminates are predominated: transverse cracking and delamination. However, this second mode of damage is not accounted in our numerical model. After a general review of experimental approaches of observed behavior of laminates, the focus is laid on predicting laminate behavior based on continuum damage mechanics. In this study, a continuum damage model based on ply failure criteria is presented, which is initially proposed by Ladevèze. To reveal the effect of different stacking sequence of the laminate; such as thickness and the interior or exterior disposition of the 0° and 90° oriented layers in the laminate, an equivalent damage accumulation which cover all ply failure mechanisms has been predicted. However, the solution algorithm using finite element analysis which implements progressive failure analysis is summarized. The results of the numerical computation have been justified by the previous published experimental observations of the authors.

scholarly journals On the Analysis of PM/FM Noise Radar Waveforms Considering Modulating Signals with Varied Stochastic Properties

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1727
Author(s):  
Leandro Pralon ◽  
Gabriel Beltrao ◽  
Alisson Barreto ◽  
Bruno Cosenza
Keyword(s):  
Random Phase ◽  
Research Area ◽  
General Term ◽  
Radar Systems ◽  
Noise Radar ◽  
Random Samples ◽  
Spectrum Density ◽  
Important Research Area ◽  
Radar Waveforms ◽  
Stochastic Properties

Noise Radar technology is the general term used to describe radar systems that employ realizations of a given stochastic process as transmit waveforms. Originally, carriers modulated in amplitude by a Gaussian random signal, derived from a hardware noise source, were taken into consideration, justifying the adopted nomenclature. With the advances made in hardware as well as the rise of the software defined noise radar concept, waveform design emerges as an important research area related to such systems. The possibility of generating signals with varied stochastic properties increased the potential in achieving systems with enhanced performances. The characterization of random phase and frequency modulated waveforms (more suitable for several applications) has then gained considerable notoriety within the radar community as well. Several optimization algorithms have been proposed in order to conveniently shape both the autocorrelation function of the random samples that comprise the transmit signal, as well as their power spectrum density. Nevertheless, little attention has been driven to properly characterize the stochastic properties of those signals through closed form expressions, jeopardizing the effectiveness of the aforementioned algorithms as well as their reproducibility. Within this context, this paper investigates the performance of several random phase and frequency modulated waveforms, varying the stochastic properties of their modulating signals.

Numerische Abbildung von Beton mit einem plastischen Schädigungsmodell – Grundlegende Untersuchungen zu Normalbeton und UHPC/Finite element simulation of concrete with a plastic damage model – Basic studies on normal strength concrete and UHPC

Bauingenieur ◽  
2015 ◽  
Vol 90 (06) ◽  
pp. 252-264 ◽  
Author(s):  
Dominik Kueres ◽  
Alexander Stark ◽  
Martin Herbrand ◽  
Martin Classen
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Damage Model ◽  
Normal Strength Concrete ◽  
Numerische Simulation ◽  
Plastic Damage ◽  
Element Simulation ◽  
Finite Elemente ◽  
Normal Strength ◽  
Basic Studies

Die numerische Simulation des Tragverhaltens von Beton- und Stahlbetonkonstruktionen mit nicht-linearen Finite-Elemente-Modellen gewinnt in der konstruktiven Ingenieurpraxis zunehmend an Bedeutung. In kommerziellen Finite-Elemente-Programmen stehen dem Anwender unterschiedliche Möglichkeiten zur Abbildung des Betonverhaltens in Form von plastischen Materialmodellen zur Verfügung. Zur Anwendung dieser Materialmodelle ist dabei in der Regel die Kenntnis des Betontragverhaltens unter einaxialer Druck- und Zugbeanspruchung erforderlich. Im vorliegenden Beitrag werden verschiedene Ansätze zur mathematischen Beschreibung dieser konstitutiven Beziehungen für Normalbeton und ultrahochfesten Beton (UHPC) vorgestellt und im Hinblick auf ihre Anwendbarkeit in plastischen Materialmodellen untersucht. Darauf aufbauend werden numerische Simulationen mit einem plastischen Schädigungsmodell unter Verwendung eines einheitlichen Parametersatzes durchgeführt und mit den Ergebnissen experimenteller Untersuchungen verglichen. Die Untersuchungen umfassen hierbei Materialprüfungen an Normalbeton und UHPC unter verschiedenen ein- und mehraxialen Spannungszuständen. Durch die Wahl geeigneter konstitutiver Beziehungen kann für die untersuchten Spannungszustände eine gute Übereinstimmung zwischen simuliertem und experimentell ermitteltem Betontragverhalten erreicht werden.

Climate change and employment relations

2017 ◽  
Vol 59 (5) ◽  
pp. 670-679 ◽  
Author(s):  
Caleb Goods
Keyword(s):  
Climate Change ◽  
Research Area ◽  
Research Note ◽  
Employment Relations ◽  
Important Research ◽  
Workplace Relations ◽  
Important Research Area

A central, yet overlooked, aspect of contemporary employment relations is the growing impact climate change is having on workplace relations. This research note outlines how climate change and workplace relations are linked, the minimal academic focus this important research area has received and the limited response from employment relations actors to the climate change challenge. Some examples of ‘climate bargaining’ are given to demonstrate both the connection between employment relations and climate change and to provide possible models for meaningfully advancing climate change actions in the workplace.

A multiscale elasto-plastic damage model for the nonlinear behavior of 3D braided composites

2019 ◽  
Vol 171 ◽  
pp. 21-33 ◽  
Author(s):  
Chunwang He ◽  
Jingran Ge ◽  
Dexing Qi ◽  
Jiaying Gao ◽  
Yanfei Chen ◽  
...  
Keyword(s):  
Damage Model ◽  
Nonlinear Behavior ◽  
Braided Composites ◽  
3D Braided Composites ◽  
Plastic Damage

MULTI-LEVEL DOCUMENT IMAGE SEGMENTATION USING MULTI-LAYER PERCEPTRON AND SUPPORT VECTOR MACHINE

2012 ◽  
Vol 26 (06) ◽  
pp. 1253002 ◽  
Author(s):  
YAN ZHANG ◽  
BIN YU ◽  
HAI-MING GU
Keyword(s):  
Support Vector Machine ◽  
Image Segmentation ◽  
Research Area ◽  
Document Image ◽  
Support Vector ◽  
Multi Layer Perceptron ◽  
Document Image Analysis ◽  
Important Research Area ◽  
Multi Level ◽  
Document Image Segmentation

Document image segmentation is an important research area of document image analysis which classifies the contents of a document image into a set of text and non-text classes. Previous existing methods are often designed to classify text and halftone therefore they perform poorly in classifying graphics, tables and circuit, etc. In this paper, we present a robust multi-level classification method using multi-layer perceptron (MLP) and support vector machine (SVM) to segment the texts from non-texts and thereafter classify them as tables, graphics and halftones. This method outperforms previously existing methods by overcoming various issues associated with the complexity of document images. Experimental results prove the effectiveness of our proposed method. By virtue of our multi-level classification approach, the text components, halftone components, graphic components and table components are accurately classified respectively which would highly improve OCR accuracy to reduce garbage symbols as well as increase compression ratio thereafter simultaneously.

Could the Substance Misuse of a Relative be an Important Factor for Those Seeking Help for Anxiety and Depression? A Preliminary Prevalence Study within Improving Access to Psychological Therapies (IAPT)

2016 ◽  
Vol 44 (6) ◽  
pp. 723-729 ◽  
Author(s):  
Elizabeth Newton ◽  
Nicola Shepherd ◽  
Jim Orford ◽  
Alex Copello
Keyword(s):  
Severe Depression ◽  
Routine Data ◽  
Research Area ◽  
Close Relative ◽  
Service Users ◽  
Depression And Anxiety ◽  
Psychological Therapies ◽  
Important Research Area ◽  
Close Relatives ◽  
Drug Problems

Background: The psychological difficulties and emotional impacts resulting from the substance use of close relatives constitute a large, underestimated and frequently unidentified health burden. The development of primary care mental health services in response to the Improving Access to Psychological Therapies initiative provides an opportunity to investigate this in more depth. Aims: A preliminary exploration of prevalence of IAPT service-users being treated for moderate-severe depression and/or anxiety who report that they have relatives with alcohol and/or drug problems. To explore the characteristics of the sample including comparison with those without a substance misusing relative. Method: One hundred service users completed a brief questionnaire. Routine data on depression and anxiety symptoms were accessed for the full consenting sample. Descriptive statistics were used to explore the family members of substance users and differences to the rest of the sample. Results: Twenty-two of the 100 IAPT service users reported having a close relative whose use of substances was of concern to them. The group with a relative who used substances were more depressed at the beginning of treatment than the rest of the sample. Conclusions: A significant number of people seeking psychological help for depression and anxiety within IAPT services reported being concerned about a close relative who misuses substances. They may be more distressed than those without a relative who misuses substances. Further exploration is warranted but preliminary findings indicate that this is an important research area with significant clinical implications.

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