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| | # Prepare contact model which describes the rule of interaction | | # Prepare contact model which describes the rule of interaction |
| | # Prepare EDEM simulation | | # Prepare EDEM simulation |
| − | # Measure something and compare it to analytic
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| | ==Who we are== | | ==Who we are== |
| − | * [[Степанов Алексей]] (responsible for contact model) | + | * [[Степанов Алексей]] |
| − | * [[Дзенушко Дайнис]] (responsible for factory and EDEM simulation) | + | * [[Дзенушко Дайнис]] |
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| | ==Factory== | | ==Factory== |
| − | We create 2 particles on a distance 0.1m and rotated at an angle of 5-15 () degrees;<br> | + | We create 2 particles |
| − | These particles are of 2 types "small" and a "big" one; Big particle has identity matrix as rotation matrix; Small particle is rotated using rotation matrix <br>
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| − | Particles's velocity and angular velocity equals to zero;<br>
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| − | Y and Z coordinates are the same (0.5,0.5); Only X is different (0.45 for "big" and 0.55 for "small");<br>
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| − | *For small particle:<br>
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| − | double OrientAngle = pi/12; // angle between particles in Radians<br>
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| − | orientation[0] = 1.0; // Rotating particle. X axis.<br>
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| − | orientation[4] = cos(OrientAngle);<br>
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| − | orientation[5] = -sin(OrientAngle);<br>
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| − | orientation[7] = sin(OrientAngle);<br>
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| − | orientation[8] = cos(OrientAngle);<br>
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| − | ==Contact Model==
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| − | In our project we used simple contact model.<br>
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| − | All central forces we made zero. Also we made zero all torques except torque, which operates on a "small" particle. <br>
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| − | calculatedElem2AdditionalTorqueX = 1.0 * (elem1Orientation[7] * elem2Orientation[4] + elem2Orientation[5] * elem1Orientation[4] ); <br>
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| − | In this formula С = 1.0
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| − | ==EDEM simulation==
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| − | ===Globals:===
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| − | Interaction: Particle to particle<br>
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| − | Model: our contact model<br>
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| − | No gravity<br>
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| − | There are two materials "material" and "material_2" with different density for "material" 1000 for "material_2" 1.7e+05 <br>
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| − | Restitution: 0.5<br>
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| − | No static and rolling friction<br>
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| − | ===Particles:===
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| − | We create particles of 2 types;"big" with big moment of inertia (100kgm2 X-axis) and "small"(0.000285kgm2 X-axis);Both particles are made of 2 surfaces placed along Z-axis on a distance of 2 particle radius
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| − | ==Measures==
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| − | We measured the period of oscillation<br>
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| − | ===Analytics===
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| − | <math>T = 2\pi\sqrt{\frac{C}{\theta}} = 0.106</math>
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| − | ===Integration===
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| − | We measured period using the Graph of angular velocity and got the result <br>
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| − | <math>T = 0.082</math>
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| − | ==Results==
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| − | So we got the result that is different to the analytic;<br>
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| − | Then we wrote small programm on C# that integrates the equalation in a simple way and got the result<br>
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| − | <math>T = 0.106</math><br>
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| − | We checked all in EDEM simulation; Changing parameters of particles, roll stiffness didn't gave any difference the results stayed different to analytic.
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| − | ==Additional Measures==
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| − | We chacked translational kinetic and potentional energy and they really equals to zero<br>
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| − | Graph of Rotational Kinetic energy
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| − | <gallery widths=580px heights=350px perrow = 1>
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| − | Файл:EDEM_Kin_Energy.jpg
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| − | </gallery>
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| − | As we can see the maximum of Kinetic energy is conserving. This graph was extended to 100 seconds(~1220 period)<br>
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| − | and conservation of Rotational Kinetic energy was prooved. Time step ~9.75e-07s.
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| − | [[Category: Студенческие проекты]]
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| − | [[Category: Механика дискретных сред]]
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| − | [[Category: Программирование]]
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