Corrigendum: Two blocks connected by a string with variable tension: a dynamic case (2020 Phys. Educ. 
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При прохождении стружечноклеевой массы по ленточному прессу и формования ее в изделие под вальцами происходит постоянное изменение свойств материала. От несвязной сыпучей композиции материал в результате пьезотермообработки должен преобразоваться в монолитное фасонное изделие. Силовое и температурные воздействия в процессе обработки вызывают в материале, а затем и в готовом изделии переменное напряженное состояние, которое в значительной степени определяет целостность и окончательные механические свойства готовой продукции. В настоящей статье исследуются напряженные состояния в наиболее опасном месте пресса – под профилирующим вальцом. Основная цель исследования заключается в попытке объяснить появление дефектов изделия и наметить конструктивные и технологические мероприятия по их устранению или хотя бы смягчению. При проведении предварительных экспериментов по изготовлению погонажных изделий из стружечноклеевой массы был обнаружен ряд основных недостатков. Большинство дефектов связано с процессом профилирования и возникают под профилирующим барабаном. Очевидно, причиной всех отмеченных дефектов являются экстремальные условия деформирования материала под барабаном и несоответствие термомеханического состояния обрабатываемого материала характеру деформирования. На основании проведенных исследований можно сделать основные выводы: продольный изгиб при прокатке изделий из стружечноклеевой массы представляет существенную опасность и может быть причиной расслоения изделий по ширине; уменьшение вредного влияния продольного изгиба по ширине изделия может быть достигнуто за счет его интенсивного разогрева и ограничения отверждения связующего под вальцами; диаметры профилирующих барабанов необходимо делать максимальными по конструктивным соображениям; оптимальным вариантом является профилирование на прямолинейных участках, где радиус равен бесконечности; необходимо обеспечить жесткую синхронизацию линейных скоростей по всем точкам контакта изделия с рабочими органами прессового оборудования. Такие условия автоматически удовлетворяется в гусеничном прессе, что дополнительно характеризует его достоинства. When shaving and glue mix passing through a tape press and its formations to product under rollers there is a continuous change of properties of material. From incoherent loose composition material as a result of a pyezoterm processing has to be transformed to a monolithic shaped product. Power and temperature influences in processing cause in material, and then and in a finished product a variable tension which substantially defines integrity and final mechanical properties of finished goods. In the present article intense states in the most dangerous place of a press – under the main roller are investigated. The main objective of research consists in attempt to explain emergence of defects of a product and to plan constructive and technological actions for their elimination or at least to mitigation. When carrying out preliminary experiments on production wooden materials from shaving and glue mix has been found a number of the main shortcomings. The majority of defects is connected with process of profiling and arise under a main drum. Obviously, extreme conditions of deformation of material under a drum and discrepancy of a thermomechanical condition of the processed material to nature of deformation are the reason of all noted defects. On the basis of the conducted researches it is possible to draw the main conclusions: the longitudinal bend when rolling products of shaving and glue mix constitutes essential danger and can be the cause of stratification of products on width; reduction of an adverse effect of a longitudinal bend on width of a product can be reached at the expense of its intensive warming up and restriction of curing binding under rollers; diameters of main drums need to be done maximum for constructive reasons; an optimal variant is profiling on straight sections where radius is equal to infinity; it is necessary to provide rigid synchronization of line speeds on all contact points of a product with operating parts of the press equipment. Such conditions it is automatically satisfied in a truck press that in addition characterizes its advantages.

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Dynamic Case Based Reasoning in Fault Diagnosis and Prognosis

The 14th IEEE International Conference on Fuzzy Systems, 2005. FUZZ '05. ◽

10.1109/fuzzy.2005.1452504 ◽

2005 ◽

Cited By ~ 5

Author(s):

H. Berenji ◽

Yan Wang ◽

A. Saxena

Keyword(s):

Fault Diagnosis ◽

Case Based Reasoning ◽

Diagnosis And Prognosis ◽

Dynamic Case ◽

Fault Diagnosis And Prognosis ◽

Case Based

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Unknown Parameter Excitation and Estimation for Complex Systems With Dynamic Performances

Journal of Mechanical Design ◽

10.1115/1.4050107 ◽

2021 ◽

Vol 143 (9) ◽

Author(s):

Yi-Ping Chen ◽

Kuei-Yuan Chan

Keyword(s):

Complex Systems ◽

Simulation Models ◽

Credible Interval ◽

Specific Model ◽

Model Parameters ◽

Real Model ◽

Dynamic Case ◽

Dynamic Performances ◽

Validation Stage ◽

Setting Parameters

Abstract Simulation models play crucial roles in efficient product development cycles, therefore many studies aim to improve the confidence of a model during the validation stage. In this research, we proposed a dynamic model validation to provide accurate parameter settings for minimal output errors between simulation models and real model experiments. The optimal operations for setting parameters are developed to maximize the effects by specific model parameters while minimizing interactions. To manage the excessive costs associated with simulations of complex systems, we propose a procedure with three main features: the optimal excitation based on global sensitivity analysis (GSA) is done via metamodel techniques, for estimating parameters with the polynomial chaos-based Kalman filter, and validating the updated model based on hypothesis testing. An illustrative mathematical model was used to demonstrate the detail processes in our proposed method. We also apply our method on a vehicle dynamic case with a composite maneuver for exciting unknown model parameters such as inertial and coefficients of the tire model; the unknown model parameters were successfully estimated within a 95% credible interval. The contributions of this research are also underscored through multiple cases.

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Shifting Cases: Advancing a New Artifact for Entrepreneurial Education

Journal of Business Anthropology ◽

10.22439/jba.v8i2.5849 ◽

2019 ◽

Vol 8 (2) ◽

pp. 211-227

Author(s):

Marlo Rencher

Keyword(s):

Early Stage ◽

Safety Net ◽

Boundary Object ◽

Entrepreneurial Activity ◽

Entrepreneurial Education ◽

New Approach ◽

Making Sense ◽

Midwestern University ◽

Dynamic Case

Entrepreneurship, as applied here, involves helping students develop an entrepreneurial mindset by working in a university-supported startup that lacks the artificiality of a simulation or the safety net of heavy financial subsidization. This article chronicles an organizational-wide change at a private Midwestern university and the development of a new “artifact”—the dynamic case study—to complement a new approach to business and entrepreneurial education. After reviewing the function of case studies in a teaching and research context, I consider this new kind of case study as a boundary object and means for making sense of early stage entrepreneurial activity.

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Parameter Selection in the Parameter Estimation of Grade Transitions in a Polyethylene Plant

Studies in Engineering and Technology ◽

10.11114/set.v3i1.887 ◽

2015 ◽

Vol 3 (1) ◽

pp. 1

Author(s):

Niklas Andersson ◽

Per-Ola Larsson ◽

Johan Åkesson ◽

Niclas Carlsson ◽

Staffan Skålén ◽

...

Keyword(s):

Parameter Estimation ◽

Steady State ◽

State Parameter ◽

Parameter Selection ◽

Selection Algorithm ◽

Parameter Estimations ◽

Dynamic Case ◽

Nominal Parameter ◽

Best Parameter ◽

Parameter Values

A polyethylene plant at Borealis AB is modelled in the Modelica language and considered for parameter estimations at grade transitions. Parameters have been estimated for both the steady-state and the dynamic case using the JModelica.org platform, which offers tools for steady-state parameter estimation and supports simulation with parameter sensitivies. The model contains 31 candidate parameters, giving a huge amount of possible parameter combinations. The best parameter sets have been chosen using a parameter-selection algorithm that identified parameter sets with poor numerical properties. The parameter-selection algorithm reduces the number of parameter sets that is necessary to explore. The steady-state differs from the dynamic case with respect to parameter selection. Validations of the parameter estimations in the dynamic case show a significant reduction in an objective value used to evaluate the quality of the solution from that of the nominal reference, where the nominal parameter values are used.

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Static and Dynamic Response of a Beam on a Winkler Elastic Foundation

Volume 6: 5th International Conference on Multibody Systems, Nonlinear Dynamics, and Control, Parts A, B, and C ◽

10.1115/detc2005-84384 ◽

2005 ◽

Cited By ~ 1

Author(s):

Timour M. A. Nusirat ◽

M. N. Hamdan

Keyword(s):

Elastic Foundation ◽

Governing Equation ◽

Initial Value Problem ◽

Nonlinear Partial Differential Equation ◽

Static Case ◽

Initial Value ◽

Characteristic Curves ◽

System Parameters ◽

Winkler Elastic Foundation ◽

Dynamic Case

This paper is concerned with analysis of dynamic behavior of an Euler-Bernoulli beam resting on an elastic foundation. The beam is assumed to be subjected to a uniformly distributed lateral static load, have an initial quarter-sine shape deflection. At one end, the beam is assumed to be restrained by a pin, while at the other end, the beam is assumed to be restrained by a torsional and a translational linear spring. The beam is modeled by a nonlinear partial differential equation where the nonlinearity enters the governing equation through the beam axial force. In the static case, because of a unique feature of governing equation, the analysis was carried out using the theory of linear differential equations, but takes into account the effect of actual deflection on the induced axial thrust. In the dynamic case, stability analysis of the beam is carried out by calculating the nonlinear frequencies of free vibration of the beam about its static equilibrium configuration. The assumed mode method is used to discretize and find an equivalent nonlinear initial value problem. Then the harmonic balance is used to obtain an approximate solution to the nonlinear oscillator described by the equivalent initial value problem. The analyses of results were carried out for a selected range of values of the system parameters: foundation elastic stiffness, lateral load, and maximum beam edge deflection. In the static case the results are presented as characteristic curves showing the variation of the beam static deflection and associated bending moment distribution with each of the above system parameters. In the dynamic case, the presented characteristic curves show the variation of the nonlinear natural frequency corresponding to the first and the second modes over a range of each of the above system parameters.

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Frequency-Dependent Tensile and Compressive Effective Moduli of Elastic Solids With Randomly Distributed Two-Dimensional Microcracks

Journal of Applied Mechanics ◽

10.1115/1.4030538 ◽

2015 ◽

Vol 82 (8) ◽

Cited By ~ 23

Author(s):

Youxuan Zhao ◽

Yanjun Qiu ◽

Laurence J. Jacobs ◽

Jianmin Qu

Keyword(s):

Wave Attenuation ◽

Two Dimensional ◽

Effective Moduli ◽

The Finite Element Method ◽

Elastic Solids ◽

Frequency Dependent ◽

Micromechanics Models ◽

Dynamic Case ◽

Crack Faces ◽

Analytical Expressions

This paper develops micromechanics models to estimate the tensile and compressive elastic moduli of elastic solids containing randomly distributed two-dimensional microcracks. The crack faces are open under tension and closed under compression. When the crack faces are closed, they may slide against one another following the Coulomb's law of dry friction. The micromechanics models provide analytical expressions of the tensile and compressive moduli for both static and dynamic cases. It is found that the tensile and compressive moduli are different. Further, under dynamic loading, the compressive and tensile moduli are both frequency dependent. As a by-product, the micromechanics models also predict wave attenuation in the dynamic case. Numerical simulations using the finite element method (FEM) are conducted to validate the micromechanics models.

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