Development Of Computer Simulation Model Research Articles

Infill parameters influence over the natural frequencies of ABS specimens obtained by extrusion-based 3D printing

Purpose The mechanical performances of 3D-printed parts are influenced by the manufacturing variables. Many studies experimentally evaluate the impact of the process parameters on specimens’ static and dynamic behavior with the aim of tailoring the mechanical response of the prints. However, this experimental approach is hampered by the very large number of parameters, 3D printers and materials, the development of computer simulation models being thus required. In the context, this study aims to fill a gap by experimentally investigating the influence of infill related parameters over the vibrations of 3D-printed specimens, as well as to propose and validate a parametric finite element (FE) model for the prediction of eigenfrequencies. Design/methodology/approach A generally applicable FE model is not yet available for the 3D printing technology based on the material extrusion process due to the large number of parameters settings that determine a large variability of outcomes. Hence, the idea of developing numerical simulation models that address sets of parameters and assess their impact on a certain mechanical property. For the natural frequency, the influence of the infill density and infill line width is studied in this paper. An FE script that automates the generation of the model geometry by using the considered set of parameters is developed and run. The results of the modal analysis are compared to the experimental values for validating the script. Findings Based on the experimental results, a linear regression between the weight of the part and the first natural frequency is established. The response surfaces indicate that the infill density is the most significant parameter of influence. The weight-frequency function is then used for the prediction of the natural frequency of specimens manufactured with other infill parameters and values, including different infill patterns. Practical implications As the malfunctions or mechanical damages can be caused by the resonant vibration of parts during use, this research develops a FE-parameterized model that evaluates and predicts the eigenfrequencies of 2D printed parts to prevent these undesirable events. The targeted functional applications are those in which 3D-printed polymer parts are used, such as drone arms or drone propellers. Originality/value This research studies the influence of process parameters on the natural frequency of 3D-printed polylactic acid specimens, a topic scarcely addressed in literature. It also proposes a new approach for the development of parameterized FE models for sets of parameters, instead of a general model, to reduce the time and resources allocated to the experimental tests. Such a model is provided in this paper for evaluating the influence of infill parameters on 3D prints eigenfrequency. The numerical model is validated for other infill settings.

DEVELOPMENT OF VIRTUAL LABORATORIES ON THE TOPIC "STUDY OF THE STRUCTURE AND DEVELOPMENT OF SPONGES ON THE EXAMPLE OF FRESHWATER BADYAGA". TYPE SPONGIA, CLASS DEMOSPONGIA, ORDER SPONGILLIDAE, SUPERVISOR SPONGILLA

This article examines the development of computer simulation models for laboratory work on the subject "Invertebrate Zoology". In particular, simulation models are shown for the following laboratory work: the external structure of the sponge, the accumulation of amoebocytes, the internal and external structure of the sponge, stinging cells, water circulation, the movement of the freshwater and longitudinal section of the hydra, the general view of the colony, the colony of the hydroid polyp in close-up, budding of jellyfish in blastostyle, parenchymula, planula, formed by a new colony.

System Approach, Modeling, Simulation as Educational Technologies in Algorithm Development and Programming

The important method of current educational research is system approach, modeling and computer simulation of real systems and real processes. System approach, modeling and simulation have been found as one of the suitable method of developing theoretical knowledge of algorithm development and programming. The paper presents method of modeling and simulation in simulation of real physical phenomenon of the kinematics of solid bodies. The solution is demonstrated step by step – it starts with the system identification of the physical problem followed by creation of conceptual model. Finally development of computer simulation model is presented. The simulation model is done by programming in MS Excel worksheet, through which the solution and visualization of the problem is reached.

Establishment and Development of Computer Simulation Model on Fruit and Vegetable Microbial Fermentation Process

This study aims to develop a set of computer simulation model on fruit and vegetable microbial fermentation process. The existing data is used to model the decomposition process of the fruit and vegetable through the ordinary differential equation. The model is validated through the mathematical simulation software MATLAB and the experience shows that the method can truly reproduce the decomposition process of the fruit and vegetable under different circumstances. The research can provide an important technical means for the preservation and corrosion prevention of fruit and vegetable.

A Patient-specific in vivo Tumor and Normal Tissue Model for Prediction of the Response to Radiotherapy

Integration of multiscale experimental cancer biology through the development of computer simulation models seems to be a necessary step towards the better understanding of cancer and patient- individualized treatment optimization. The integration of a four-dimensional patient-specific model of in vivo tumor response to radiotherapy developed by our group with a model of slowly responding normal tissue based on W. Duechting's approach is presented in this paper. The case of glioblastoma multiforme and its surrounding neural tissue is addressed as a modeling paradigm. A cubic discretizing mesh is superimposed upon the anatomic region of interest as is reconstructed from pertinent imaging (e.g. MRI) data. On each geometrical cell of the mesh the most crucial biological "laws" e.g. metabolism, cell cycling, tumor geometry changes, cell kill following irradiation etc. are applied. Slowly responding normal neural tissue is modeled by a functional compartment containing indivisible cells and a divisible compartment containing glial cells. The model code has been executed for a simulated period normally covering the radiotherapy course duration and extending a few days after its completion. The following schemes have been simulated: standard fractionation, hyperfractionation, accelerated fractionation, accelerated hyperfractionation and hypofractionation. The predictions are in agreement with the outcome of the RTOG 83-02 phase I/II trial, the retrospective study conducted by Sugawara et al. and the theoretical predictions of Duechting et al. The presented model, although oversimplified, may serve as a basis for a refined simulation of the biological mechanisms involved in tumor and normal tissue response to radiotherapy.

Numerical Simulation of Cold Compaction of 3D Granular Packings

During cold compaction processes loose powder is pressed under tooling action in order to produce complex shaped engineering components. Here, the analysis of the plastic deformation of granular packings is of fundamental importance to the development of computer simulation models for industrial forming processes. Powders can be idealized by packing discrete particles, where each particle is a sphere meshed with finite elements. During pressing, particles are deformed by elastic-plastic hardening where friction is present at each contact. The pressing of an isolated particle followed by a body centered cubic packing was compared with numerical prediction and experimental data. The analysis was focused on the interaction between particles and the global response expressed in force-displacement curve during compaction. The accuracy of the numerical models was also analyzed for high relative densities up to 0.95.

System Dynamics Modeling for Public Health: Background and Opportunities

The systems modeling methodology of system dynamics is well suited to address the dynamic complexity that characterizes many public health issues. The system dynamics approach involves the development of computer simulation models that portray processes of accumulation and feedback and that may be tested systematically to find effective policies for overcoming policy resistance. System dynamics modeling of chronic disease prevention should seek to incorporate all the basic elements of a modern ecological approach, including disease outcomes, health and risk behaviors, environmental factors, and health-related resources and delivery systems. System dynamics shows promise as a means of modeling multiple interacting diseases and risks, the interaction of delivery systems and diseased populations, and matters of national and state policy.

Estimating day use social carrying capacity in Yosemite national park

Estimating Day Use Social Carrying Capacity in Yosemite National Park Carrying capacity has been a long‐standing issue in management of parks and outdoor recreation. Contemporary carrying capacity frameworks rely on formulation of indicators and standards of quality of the recreation experience to define and manage carrying capacity. This paper describes a program of research to support application of carrying capacity to Yosemite Valley, the scenic heart of Yosemite National Park, USA. Research included (1) a series of visitor surveys at selected sites within Yosemite Valley to identify indicators and standards of quality, (2) development of computer simulation models of visitor use at study sites to estimate maximum daily use levels without violating standards of quality, and (3) a park exit survey to determine the percentage of day users at study sites. Study findings are used to estimate a range of day use carrying capacities at study sites and for Yosemite Valley as a whole.

Development of computer simulation models for pedestrian subsystem impact tests

The European Enhanced Vehicle-safety Committee (EEVC/WG10 and WG17) proposed three component subsystem tests for cars to assess pedestrian protection. The objective of this study is to develop computer simulation models of the EEVC pedestrian subsystem tests. These models are available to develop a car conforming to the pedestrian subsystem test requirements. The pedestrian subsystem test models were developed and validated in this study. However, some improvements are still needed in these models to make them more reliable in simulating the pedestrian subsystem tests to develop a car conforming to the test requirements.

カミヤ連続蒸解釜のシミュレーションモデルの開発 Ｌｏ‐Ｓｏｌｉｄｓ蒸解針葉樹クラフトパルプの強度と歩留まりの最適化

カミヤ連続蒸解釜のシミュレーションモデルの開発 Ｌｏ‐Ｓｏｌｉｄｓ蒸解針葉樹クラフトパルプの強度と歩留まりの最適化

Assessing chemical stress in aquatic ecosystems: remarks on the need of an integrative approach

This paper that serves as a prelude to a series of papers on the theme ‘Pesticide stress in freshwater ecosystems’, has three main objectives. First it outlines the importance of ecological expertise assessing the risks of discharge of pesticides into aquatic environments; second, it discusses possible contributions of ecotoxicological experiments to ecological theory; and third, it advocates the need for an integrative approach in stress-ecology. This approach is based on descriptive ecology, experimentation in the laboratory and in model ecosystems, and on the development of computer simulation models.

Synthesis and Generation of Surfaces Milled by Ball Nose End Mills Under Tertiary Cutter Motion

The synthesis and generation of milled surfaces under tertiary cutter motion of the spindle with ball nose end mills was investigated and shown that a multitude of surface topographies can be generated. A basis for theoretical investigation was established by the derivation of the tooth path equations and the development of computer simulation models for ball nose end milling processes. The accuracy of the developed computer model and the feasibility of the tertiary cutter motion concept were subsequently authenticated and verified by the agreement between the experiments and the computer simulations.