scholarly journals Control algorithm for an elastic-viscoplastic model to study processes of shock interaction of bodies

2021 ◽  
Vol 21 (2) ◽  
pp. 191-199
Author(s):  
V. L. Lapshin ◽  
Е. V. Zenkov
Keyword(s):  
Process Model ◽  
Mechanical Characteristics ◽  
Dynamic Processes ◽  
Engineering Practice ◽  
Shock Interaction ◽  
Plastic Deformations ◽  
Viscoplastic Model ◽  
Shock Process ◽  
Plastic Transformation ◽  
The Impact

Introduction. In engineering practice, dynamic processes, with the help of which mechanics of interaction of machine components and structural elements are described and studied, are of great importance. These dynamic processes are the cause of large deformations leading to the destruction. The research objective is to develop a more accurate shock simulation algorithm through the controlled transformation of the mechanorheological shock process model from elasticviscous to elastic-viscoplastic.Materials and Methods. Differential equations of the model movement are proposed. The conditions for the transformation of the model during the transition from elastic to plastic deformations, from the stage of loading the model to the stage of unloading under the shock interaction with the surface, are considered. When calculating deformations, the assumption is made that elastic and plastic deformations occur simultaneously from the very onset of the impact. The model functioning method is considered in detail, the algorithm of the model operation is developed, the logic of its functioning is described in detail.Results. To study shock processes, a mechanoreological elastic-viscoplastic model was developed. An important parameter of the model is the force corresponding to the onset of plastic deformation. As a result of the research, a more perfect algorithm was created, and a new computer program was developed to study the shock process using an elasticviscoplastic model with an adjustable elastic-plastic transformation. Discussion and Conclusions. The results obtained can be used to improve the accuracy and reliability of simulation of shock processes in order to further develop the techniques for determining the physical and mechanical characteristics of materials by shock methods. Knowledge of the mechanical characteristics of materials is required when solving various research problems through mathematical modeling of vibration and shock processes. At the same time, an important task is to adapt the design model to the real shock process, for which it is required to develop appropriate methods and techniques. 

Scale Development: Measuring Job-Family Incivility

2019 ◽  
pp. 31-48
Author(s):  
W G S Mahalekamge ◽  
Nilakshi W K Galahitiyawe
Keyword(s):  
Scale Development ◽  
Work Environment ◽  
Development Process ◽  
Workplace Incivility ◽  
Dynamic Processes ◽  
Validity And Reliability ◽  
Development Approach ◽  
The Impact ◽  
Compound Effect

The main contribution of this paper is the development of the job-family incivility scale. This paper seeks to explore the complex inter-relationships between workplace incivility and family incivility dimensions of job-family incivility by examining the dynamic processes by which job-family incivility is initiated and sustained using a scale development approach. In doing so, the paper highlights the absence of valid and reliable measures that estimate the compound effect of workplace incivility and family incivility – referred to as job-family incivility. A scale development process introduced by Quazi et al. (2016) is presented and stages in the construction of the scale are discussed including measures of validity and reliability. The findings of the study demonstrate the validity and reliability of the job-family incivility scale developed by the current researchers. The main aims of this research are to emphasize the impact of workplace incivility and family incivility on the employees in the work environment, and to discuss the techniques that can be used to mitigate such detrimental activities.

Situational Breakdowns

2019 ◽  
Author(s):  
Anne Nassauer
Keyword(s):  
United States ◽  
Large Scale ◽  
Contextual Factors ◽  
The United States ◽  
Social Outcomes ◽  
Dynamic Processes ◽  
Collective Decisions ◽  
Different Types ◽  
The Impact

This book provides an account of how and why routine interactions break down and how such situational breakdowns lead to protest violence and other types of surprising social outcomes. It takes a close-up look at the dynamic processes of how situations unfold and compares their role to that of motivations, strategies, and other contextual factors. The book discusses factors that can draw us into violent situations and describes how and why we make uncommon individual and collective decisions. Covering different types of surprise outcomes from protest marches and uprisings turning violent to robbers failing to rob a store at gunpoint, it shows how unfolding situations can override our motivations and strategies and how emotions and culture, as well as rational thinking, still play a part in these events. The first chapters study protest violence in Germany and the United States from 1960 until 2010, taking a detailed look at what happens between the start of a protest and the eruption of violence or its peaceful conclusion. They compare the impact of such dynamics to the role of police strategies and culture, protesters’ claims and violent motivations, the black bloc and agents provocateurs. The analysis shows how violence is triggered, what determines its intensity, and which measures can avoid its outbreak. The book explores whether we find similar situational patterns leading to surprising outcomes in other types of small- and large-scale events: uprisings turning violent, such as Ferguson in 2014 and Baltimore in 2015, and failed armed store robberies.

scholarly journals Shock interactions in inviscid air and $$\hbox {CO}_2$$–$$\hbox {N}_2$$ flows in thermochemical non-equilibrium

Shock Waves ◽  
2021 ◽  
Author(s):  
C. Garbacz ◽  
W. T. Maier ◽  
J. B. Scoggins ◽  
T. D. Economon ◽  
T. Magin ◽  
...  
Keyword(s):  
Chemical Species ◽  
High Energy ◽  
Ideal Gas ◽  
Shock Interaction ◽  
Interaction Patterns ◽  
Shock Interactions ◽  
Wave Interference ◽  
Type V ◽  
The Impact ◽  
Non Equilibrium

AbstractThe present study aims at providing insights into shock wave interference patterns in gas flows when a mixture different than air is considered. High-energy non-equilibrium flows of air and $$\hbox {CO}_2$$ CO 2 –$$\hbox {N}_2$$ N 2 over a double-wedge geometry are studied numerically. The impact of freestream temperature on the non-equilibrium shock interaction patterns is investigated by simulating two different sets of freestream conditions. To this purpose, the SU2 solver has been extended to account for the conservation of chemical species as well as multiple energies and coupled to the Mutation++ library (Multicomponent Thermodynamic And Transport properties for IONized gases in C++) that provides all the necessary thermochemical properties of the mixture and chemical species. An analysis of the shock interference patterns is presented with respect to the existing taxonomy of interactions. A comparison between calorically perfect ideal gas and non-equilibrium simulations confirms that non-equilibrium effects greatly influence the shock interaction patterns. When thermochemical relaxation is considered, a type VI interaction is obtained for the $$\hbox {CO}_2$$ CO 2 -dominated flow, for both freestream temperatures of 300 K and 1000 K; for air, a type V six-shock interaction and a type VI interaction are obtained, respectively. We conclude that the increase in freestream temperature has a large impact on the shock interaction pattern of the air flow, whereas for the $$\hbox {CO}_2$$ CO 2 –$$\hbox {N}_2$$ N 2 flow the pattern does not change.

scholarly journals Evaluating interventions with victims of intimate partner violence: a community psychology approach

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Cinzia Albanesi ◽  
Carlo Tomasetto ◽  
Veronica Guardabassi
Keyword(s):  
Intimate Partner Violence ◽  
Social Services ◽  
Psychological Health ◽  
Partner Violence ◽  
Process Model ◽  
Professional Training ◽  
Phenomenological Approach ◽  
Intimate Partner ◽  
Structured Interviews ◽  
The Impact

Abstract Purpose Intimate Partner Violence (IPV) is one of the most common forms of domestic violence, with profound implication for women's physical and psychological health. In this text we adopted the Empowerment Process Model (EPM) by Cattaneo and Goodman (Psychol Violence 5(1):84–94) to analyse interventions provided to victims of IPV by a Support Centre for Women (SCW) in Italy, and understand its contribution to women’s empowerment. Method We conducted semi-structured interviews with ten women who had been enrolled in a program for IPV survivors at a SCW in the past three years. The interviews focused on the programs’ aims, actions undertaken to reach them, and the impact on the women’s lives, and were analysed using an interpretative phenomenological approach. Results Results showed that the interventions provided by the SWC were adapted according to women's needs. In the early phases, women’s primary aim was ending violence, and the intervention by the SCW was deemed as helpful to the extent it provided psychological support, protection and safe housing. Women’s aims subsequently moved to self-actualisation and economic and personal independence which required professional training, internships, and social support. Although satisfying the majority of the women’s expectations, other important needs (e.g., economic support or legal services) were poorly addressed, and cooperation with other services (e.g., police or social services) was sometimes deemed as critical. Conclusions By evaluating a program offered by a SCW to IPV survivors through the lens of the EPM model, we found that women deemed the program as effective when both individual resources and empowerment processes were promoted. Strengths, limitations and implications are discussed.

scholarly journals A Hybrid Energy System Workflow for Energy Portfolio Optimization

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4392
Author(s):  
Jia Zhou ◽  
Hany Abdel-Khalik ◽  
Paul Talbot ◽  
Cristian Rabiti
Keyword(s):  
Time Series ◽  
Gaussian Process ◽  
Electricity Market ◽  
Process Model ◽  
Net Present Value ◽  
Historical Data ◽  
Energy System ◽  
Initial Guess ◽  
Reduced Order ◽  
The Impact

This manuscript develops a workflow, driven by data analytics algorithms, to support the optimization of the economic performance of an Integrated Energy System. The goal is to determine the optimum mix of capacities from a set of different energy producers (e.g., nuclear, gas, wind and solar). A stochastic-based optimizer is employed, based on Gaussian Process Modeling, which requires numerous samples for its training. Each sample represents a time series describing the demand, load, or other operational and economic profiles for various types of energy producers. These samples are synthetically generated using a reduced order modeling algorithm that reads a limited set of historical data, such as demand and load data from past years. Numerous data analysis methods are employed to construct the reduced order models, including, for example, the Auto Regressive Moving Average, Fourier series decomposition, and the peak detection algorithm. All these algorithms are designed to detrend the data and extract features that can be employed to generate synthetic time histories that preserve the statistical properties of the original limited historical data. The optimization cost function is based on an economic model that assesses the effective cost of energy based on two figures of merit: the specific cash flow stream for each energy producer and the total Net Present Value. An initial guess for the optimal capacities is obtained using the screening curve method. The results of the Gaussian Process model-based optimization are assessed using an exhaustive Monte Carlo search, with the results indicating reasonable optimization results. The workflow has been implemented inside the Idaho National Laboratory’s Risk Analysis and Virtual Environment (RAVEN) framework. The main contribution of this study addresses several challenges in the current optimization methods of the energy portfolios in IES: First, the feasibility of generating the synthetic time series of the periodic peak data; Second, the computational burden of the conventional stochastic optimization of the energy portfolio, associated with the need for repeated executions of system models; Third, the inadequacies of previous studies in terms of the comparisons of the impact of the economic parameters. The proposed workflow can provide a scientifically defendable strategy to support decision-making in the electricity market and to help energy distributors develop a better understanding of the performance of integrated energy systems.

Rupture by impact-induced fatigue of a copper foil strip embedded in a multifunctional composite material

2021 ◽  
pp. 002199832199432
Author(s):  
Yacine Ouroua ◽  
Said Abdi ◽  
Imene Bachirbey
Keyword(s):  
Composite Material ◽  
Mechanical Characteristics ◽  
Glass Fibers ◽  
Energy Levels ◽  
Fatigue Tests ◽  
Repeated Impact ◽  
Aeronautical Industry ◽  
Repeated Impacts ◽  
Cracking Mode ◽  
The Impact

Multifunctional composite materials are highly sought-after by the aerospace and aeronautical industry but their performance depends on their ability to sustain various forms of damages, in particular damages due to repeated impacts. In this work we studied the mechanical behavior of a layered glass-epoxy composite with copper inserts subjected to fatigue under repeated impacts with different energy levels. Damage evolution as a function of impact energy was carefully monitored in order to determine the effect of the copper inserts on mechanical characteristics of the multifunctional composite, such as endurance and life. Results of repeated impact tests show that electric current interruption in the copper inserts occurs prior to the total perforation of the composite material, and after about 75% of the total number of impacts to failure. This is the case for the three energy levels considered in this study, [Formula: see text] = 2, 3 and 4 Joules. The epoxy resin was dissolved chemically in order to preserve the mechanical structure of the damaged copper inserts and the composite fibers for further inspection and analysis. Scanning electron microscopy (SEM) of the fractured copper inserts revealed interesting information on the nature of the damage, including information on plastic deformation, strain hardening, cracking mode, temperature increase during the impacts, and most importantly the glass fibers and their roles during the impact-fatigue tests.

Study on Impact Compaction of Aeolian Sand Subgrade and its Effect Evaluation

2011 ◽  
Vol 378-379 ◽  
pp. 370-373
Author(s):  
Yu Qing Yuan ◽  
Xuan Cang Wang ◽  
Hui Jun Shao
Keyword(s):  
Rayleigh Wave ◽  
Impact Force ◽  
Engineering Practice ◽  
Effect Evaluation ◽  
Aeolian Sand ◽  
Field Compaction ◽  
Vibratory Compaction ◽  
Strength And Stiffness ◽  
The Impact ◽  
Elastic Stage

In order to solve the problem of aeolian sand subgrade compaction, we studied the technology of impact compaction, applied it to the engineering practice and analyzed its effect with Rayleigh wave. The technology of impact compaction can combine the compaction of potential energy and kinetic energy and make it easier for the materials to reach their elastic stage. With the combined function of "knead-roll-impact", the impact compaction road roller can compact the soil body and offer 6～10 times impact force and 3～4 times the depth of influence more than the vibratory roller. The impact compaction methods of aeolian sand subgrade were put forward. The comparative field compaction tests between impact and vibratory compaction are carried through, which are detected by Rayleigh wave. The results show that the impact compaction can make the density of the aeolian sand subgrade 2～5% higher than the vibratory compaction, and reach the influence depth of 7 metres. To sum up, the impact compaction can clearly increases the strength and stiffness of aeolian sand subgrade with a dynamic elastic modulus of 202.63MPa.

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