scholarly journals Using the asymptotic approximation of the Maxwell element model for the analysis of stress in a conveyor belt

2021 ◽  
Vol 6 (7 (114)) ◽  
Author(s):  
Oleh Pihnastyi ◽  
Svіtlana Chernіavska
Keyword(s):  
Relaxation Time ◽  
Material Properties ◽  
Operating Mode ◽  
Element Model ◽  
Conveyor Belt ◽  
Oscillation Period ◽  
Dynamic Stresses ◽  
Maxwell Element ◽  
Stress And Deformation ◽  
The Relationship

The features of the propagation of dynamic stresses in a conveyor belt, the material properties of which correspond to the Maxwell element model, are considered. Analytical expressions are presented for calculating the dynamic elastic modulus, the loss modulus, and the angle of mechanical loss depending on the frequency of longitudinal oscillations in the belt of an extended transport conveyor. To analyze the dynamic stress propagation process, dimensionless parameters are introduced that characterize the specific features of the viscoelastic process in a conveyor belt, the material properties of which correspond to the Maxwell element model. The transition to the dimensionless Maxwell element model is made and the analysis of the relationship between stress and deformation of a conveyor belt element for extremely large and small values of dimensionless parameters is made. The substantiation of the scope of the Maxwell element model is given. It is shown that at sufficiently high frequencies of longitudinal stress oscillations in a conveyor belt, at which the oscillation period is much less than the characteristic oscillation decay time, the relationship between stress and deformation of the conveyor belt element corresponds to Hooke's law. A qualitative analysis of the relaxation time was carried out for a conveyor belt material, the properties of which correspond to the Maxwell element model. The analysis of the propagation of dynamic stresses in the conveyor belt for the characteristic operating modes of the transport conveyor is carried out. The conveyor operating mode with a constant deformation rate of the belt element; the mode in which a constant load is suddenly applied to the belt element; the conveyor operating mode with an instantly applied load to the belt element were investigated. It was determined that in cases where the characteristic process time significantly exceeds the stress relaxation time in the conveyor belt or the longitudinal oscillation period is much less than the stress relaxation time in the conveyor belt, the Maxwell element model can be replaced with a sufficient degree of accuracy by the Hooke element model.

scholarly journals Analysis of stress in the conveyor belt (Maxwell–element model)

2021 ◽  
pp. 74-81
Author(s):  
O.M Pihnastyi ◽  
S.M Cherniavska
Keyword(s):  
Wave Equation ◽  
Control Systems ◽  
Speed Control ◽  
Element Model ◽  
Conveyor Belt ◽  
Transport Systems ◽  
Effective Control ◽  
Characteristic Relaxation Time ◽  
Dynamic Stresses ◽  
Maxwell Element

longitudinal dynamic stresses and investigate the peculiarities of the propagation of dynamic stresses along the route of material transportation. Methodology. To calculate the value of static and dynamic stresses arising in the conveyor belt, the apparatus of mathematical physics was used. Findings. A wave equation is written that determines the propagation of longitudinal vibrations in a conveyor belt, the material of which corresponds to the Maxwell-element model. An expression is obtained for calculating the speed of propagation of elastic vibrations along the conveyor belt, the frequency of vibrations and their wavelength. The characteristic relaxation time of disturbances is determined. The method of successive approximation was used to solve the wave equation. The estimation of the characteristic time of acceleration of the conveyor belt, at which there is no destruction of the material of the conveyor belt, is given. Originality. PDE-models of conveyor-type transport systems are improved, which are used to design belt speed control systems under restrictions on speed control modes. It is shown that under the modes of acceleration or deceleration of the conveyor belt, the effects associated with the occurrence and propagation of dynamic stresses along the conveyor belt, due to the characteristics of the material corresponding to the Maxwell-element model, are insignificant. Practical value. The results obtained make it possible to determine the limitations on the modes of acceleration or deceleration of the conveyor belt, preventing its damage and increased wear. This opens up prospects for designing effective control systems for the parameters of a conveyor belt, unevenly loaded with material along the transport route.

Hardness Prediction Based on P-h Curves and Inverse Material Parameters Estimation

2015 ◽  
Vol 776 ◽  
pp. 233-238
Author(s):  
I. Nyoman Budiarsa
Keyword(s):  
Material Properties ◽  
Element Model ◽  
Parameters Estimation ◽  
Spherical Indentation ◽  
Vickers Indentation ◽  
Material Parameters ◽  
Wide Range ◽  
Constitutive Material ◽  
The Relationship ◽  
Hardness Values

The Finite Element model of Vickers indentation has been developed. The model was validated against published testing data. An approach to predict the P-h curves from constitutive material properties has been developed and evaluated based the relationship between the curvature and material properties and representative stress. The equation and procedure established was then successfully used in predict the full Vickers indentation P-h curve. FE Spherical indentation models of different radius have been developed and replay file model was developed that is able to produce data of different materials properties. Two new approaches to characterise the P-h curves of spherical indentation have been developed and evaluated. One is the full curve fitting approach while the other is depth based approach. Both approaches were proven to be adequate and effective in predicting indentation P-h curves. The concept and methodology developed is successfully used to predict hardness values (HV and HRB) of materials through direct analysis and validated with experimental data on selected sample of steels. The approaches (i.e. predict hardness from P-h curves) established was successfully used to produce hardness values of a wide range of material properties, which is then used to establish the relationship between the hardness values (HV and/or HRB) with representative stress. This provided a useful tool to evaluate the feasibility of using hardness values in predicting the constitutive material parameters with reference to accuracy and uniqueness by mapping through all potential materials ranges

scholarly journals Hydrodynamic Kelvin-Voigt Model Transportation System

2020 ◽  
Keyword(s):  
Elastic Element ◽  
Production Systems ◽  
Viscosity Coefficient ◽  
Conveyor Belt ◽  
Longitudinal Vibrations ◽  
Dynamic Stresses ◽  
Acceleration And Deceleration ◽  
Voigt Model ◽  
Speed Of Propagation ◽  
The Relationship

The hydrodynamic Kelvin-Voigt model of production systems with a flow method of organizing production is considered. The main macro parameters of the state of the production line and the relationship between them are determined. The analysis of the main characteristics of models of elastic elements, which are used to analyze the occurrence of the dynamic stresses in a moving conveyor belt, is presented. A boundary value problem for elastic longitudinal vibrations in a conveyor belt with a moving material is formulated. It is assumed that the deformation of the conveyor belt element corresponds to the Kelvin-Voigt model and there is no sliding of the moving material on the belt. When determining the forces of resistance to motion acting on an element of the belt, the recommendations of DIN 22101: 2002-08 were used. The analysis of the Kelvin-Voigt model of the elastic element is carried out and the distinctive features of the model are demonstrated. The justification of the choice of the Kelvin-Voigt model of an elastic element for describing the process of occurrence of the longitudinal vibrations in a conveyor belt is given. The dependence of the non-uniform flow of material and the magnitude of tensions in the belt is estimated. An expression is written for the speed of propagation of disturbances along a moving conveyor belt with the material. The reasons for the acceleration and deceleration of the conveyor belt associated with the uneven supply of material at the entrance of the transport system are determined. The relationship between the speed of a conveyor belt and the mass of material along a section of the conveyor is demonstrated. It is shown that an increase in the power of the electric motor at the start and acceleration of the conveyor belt, as well as a decrease in power during the braking and stopping of the conveyor belt, is the cause of the appearance of dynamic stresses in it. The characteristic phases of the initial movement of the conveyor belt with the material are analyzed. The process of occurrence of dynamic tensions with the constant and variable acceleration of the conveyor belt for the phase of acceleration and deceleration of the conveyor belt is investigated. For the analysis, a dimensionless model of a conveyor line was used. An expression is obtained for static and dynamic tensions in the conveyor belt. The amplitude of oscillations of dynamic stresses and the characteristic time of damping of oscillations in a conveyor belt is estimated. A quadratic dependence of the speed of damping of a wave of dynamic tensions with an increase in the oscillation frequency is demonstrated. An inversely proportional dependence of the characteristic decay time of the generated dynamic tensions on the value of the viscosity coefficient of the composite material of the conveyor belt is shown.

Numerical Analysis of Bridge Expansion-Induced Rail Deformation of Ballast Truck

2014 ◽  
Vol 580-583 ◽  
pp. 3208-3214 ◽  
Author(s):  
Zhen Wei Xiong ◽  
Xin Ling Liang ◽  
Xian Xing Dai ◽  
Ping Wang
Keyword(s):  
Granular Flow ◽  
Element Model ◽  
Discrete Element Model ◽  
Board Structure ◽  
Vertical Deformation ◽  
Two Dimensional ◽  
Running Safety ◽  
Bridge Plate ◽  
Ballast Track ◽  
The Relationship

when the ballast track stretch with the bridge, ballast which is near expansion joint will move confusedly. As a result, rail produced vertical deformation. The deformation will affect the running safety and comfortability of train. At present, there are two kinds of treatments which are cover board structure and baffle structure to deal ballast’s movement. Aiming at the different modes of stretching when the two kinds of structures and different arrangement condition of bridge plate are applied, the rail-sleeper-ballast discrete element model is developed by the method of two-dimensional granular flow. The relationship between rail deformation and bridge expansion is analyzed on the foundation of the model. Results show as flows: when bridge extends or shortens, rail always produced upwarp deformation. Bridge plate should arrange asymmetrically. Like this, the rail deformation decrease by 40%. And adopting the baffle structure can effectively reduce the influence of bridge expansion in ballast truck.

Finite Element Analysis of the ESTELA M1 Airplane Firewall (Representative Specimen)

2011 ◽  
Author(s):  
V. Ramirez-Elias ◽  
E. Ledesma-Orozco ◽  
H. Hernandez-Moreno
Keyword(s):  
Finite Element ◽  
Federal Aviation Administration ◽  
Element Model ◽  
Maximum Load ◽  
Load Factor ◽  
Representative Specimen ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Element Simulation ◽  
The Relationship

This paper shows the finite element simulation of a representative specimen from the firewall section in the AEROMARMI ESTELA M1 aircraft. This specimen is manufactured in glass and carbon / epoxy laminates. The specimen is subjected to a load which direction and magnitude are determined by a previous dynamic loads study [10], taking into account the maximum load factor allowed by the FAA (Federal Aviation Administration) for utilitarian aircrafts [11]. A representative specimen is manufactured with the same features of the firewall. Meanwhile a fix is built in order to introduce the load directions on the representative specimen. The relationship between load and displacement is plotted for this representative specimen, whence the maximum displacement at the specific load is obtained, afterwards it is compared with the finite element model, which is modified in its laminate thicknesses in order to decrease the deviation error; subsequently this features could be applied to perform the whole firewall analysis in a future model [10].

Experimental Identification of Material Properties of Piezoelectric Patch Transducer

2013 ◽  
Vol 486 ◽  
pp. 205-210
Author(s):  
Zuzana Lašová ◽  
Robert Zemcik
Keyword(s):  
Health Monitoring ◽  
Material Properties ◽  
Element Model ◽  
Experimental Methods ◽  
Optical Microscope ◽  
Piezoelectric Patch ◽  
Experimental Identification ◽  
Substrate Structure ◽  
Significant Difference ◽  
Voltage Signal

This work is focused on identification of material properties of piezoelectric patch transducers used e.g. for structural health monitoring before attaching to the substrate structure. Two experimental methods were concerned. At first two piezoelectric patches were supplied with a pair of collocated strain gauge rosettes. Both transducers were actuated with the same periodical signal. Significant difference in the results for two transducers was found, however it was claimed to be within tolerance by the producer. As an alternative method a measurement in an optical microscope was chosen. The patch was clamped at one side and actuated by a voltage signal. The displacement of the free end was captured by the microscope and processed in a graphical editor. Finally, a finite element model of the transducer was created and its material data were obtained by calibration with experimental data.

Integrity Assessment of Damaged Flexible Pipe Cross-Sections

2014 ◽  
Author(s):  
Guomin Ji ◽  
Bernt J. Leira ◽  
Svein Sævik ◽  
Frank Klæbo ◽  
Gunnar Axelsson ◽  
...  
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Element Model ◽  
Computer Code ◽  
Flexible Pipe ◽  
Dynamic Stresses ◽  
Integrity Assessment ◽  
Residual Capacity ◽  
Nonlinear Finite Element Model

This paper presents results from a case study performed to evaluate the residual capacity of a 6″ flexible pipe when exposed to corrosion damages in the tensile armour. A three-dimensional nonlinear finite element model was developed using the computer code MARC to evaluate the increase in mean and dynamic stresses for a given number of damaged inner tensile armor wires. The study also includes the effect of these damages with respect to the associated stresses in the pressure spiral. Furthermore, the implications of a sequence of wire failures with respect to the accumulated time until cross-section failure in a probabilistic sense are addressed.

Material Properties and Design Aspects of Folding Bicycle Frame

2011 ◽  
Vol 264-265 ◽  
pp. 777-782 ◽  
Author(s):  
M.A. Maleque ◽  
M.S. Hossain ◽  
S. Dyuti
Keyword(s):  
Material Properties ◽  
Raw Material ◽  
New Materials ◽  
Materials Properties ◽  
Advantages And Disadvantages ◽  
Bicycle Frame ◽  
Successful Design ◽  
Future Direction ◽  
The Relationship ◽  
Comprehensive Study

successful design of folding bicycle should take into account the function, material properties, and fabrication process. There are some other factors that should be considered in anticipating the behavior of materials for folding bicycle. In order to understand the relationship between material properties and design of a folding bicycle and also for the future direction in new materials with new design, a comprehensive study on the design under different conditions are essential. Therefore, a systematic study on the relationship between material properties and design for folding bicycle has been performed. The advantages and disadvantages matrix between conventional bicycle and folding bicycle is presented for better understanding of the materials properties and design. It was found that the materials properties of the folding bicycle frame such as fatigue and tensile strength are the important properties for the better performance of the frame. The relationship between materials properties and design is not straight forward because the behavior of the material in the finished product could be different from that of the raw material. The swing hinge technique could be a better technique in the design for the folding bicycle frame.

Evaluating Mechanical Properties of Ceramics by Relative Methods

2007 ◽  
Vol 336-338 ◽  
pp. 2406-2410
Author(s):  
Yi Wang Bao ◽  
Xiao Xue Bu ◽  
Yan Chun Zhou ◽  
Li Zhong Liu
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Ceramic Coatings ◽  
Relative Method ◽  
Tempered Glass ◽  
Theoretic Analysis ◽  
Surface Strength ◽  
Indirect Approach ◽  
Before And After ◽  
The Relationship

A relative method, defined as indirect approach to evaluate the material properties via the relationship between unknown properties and a known property, is proposed to estimate some properties that could not be measured by the traditional methods for ceramics. Experiments and theoretic analysis based on the relative method were carried out in this study to estimate the properties in following aspects: determining the temperature dependence of elastic modulus of some machineable ceramics by comparing the deflections; obtaining the modulus and strength of ceramic coatings supported by substrates, from the variation in properties of the rectangular beam samples before and after coating; estimating the residual stresses in tempered glass by comparing the change in the surface strength after strengthening.

scholarly journals Mechanics of the small punch test: a review and qualification of additive manufacturing materials

2021 ◽  
Vol 56 (18) ◽  
pp. 10707-10744
Author(s):  
Jonathan Torres ◽  
Ali P. Gordon
Keyword(s):  
Additive Manufacturing ◽  
Material Properties ◽  
Materials Science ◽  
Contemporary Literature ◽  
The Body ◽  
Small Punch Test ◽  
Small Punch ◽  
Punch Test ◽  
Testing Data ◽  
The Relationship

AbstractThe small punch test (SPT) was developed for situations where source material is scarce, costly or otherwise difficult to acquire, and has been used for assessing components with variable, location-dependent material properties. Although lacking standardization, the SPT has been employed to assess material properties and verified using traditional testing. Several methods exist for equating SPT results with traditional stress–strain data. There are, however, areas of weakness, such as fracture and fatigue approaches. This document outlines the history and methodologies of SPT, reviewing the body of contemporary literature and presenting relevant findings and formulations for correlating SPT results with conventional tests. Analysis of literature is extended to evaluating the suitability of the SPT for use with additively manufactured (AM) materials. The suitability of this approach is shown through a parametric study using an approximation of the SPT via FEA, varying material properties as would be seen with varying AM process parameters. Equations describing the relationship between SPT results and conventional testing data are presented. Correlation constants dictating these relationships are determined using an accumulation of data from the literature reviewed here, along with novel experimental data. This includes AM materials to assess the fit of these and provide context for a wider view of the methodology and its interest to materials science and additive manufacturing. A case is made for the continued development of the small punch test, identifying strengths and knowledge gaps, showing need for standardization of this simple yet highly versatile method for expediting studies of material properties and optimization.

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