Application of the hottest system simulation in pa

2022-07-29
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Application of system simulation in packaging design (Part 1)

in the future local war under high-tech conditions,; The packaging of military products must meet different storage methods and transportation means under adverse environmental conditions. When some precision instruments such as ventilator, electrocardiograph and B-ultrasonic machine with incorrect understanding of plastics are clarified in the transportation of combat readiness medical equipment, the sudden impact of excellent performance will produce crushing g value. The medical box is a kind of transportation package for combat medical equipment and basic health equipment with the continuous development of enterprises

the uncertainty of modern warfare, the suddenness of time and the vastness of space make it urgent to study the feasibility of using medical boxes for air transportation and air drop supply. With the continuous development of computer graphics technology, especially the development of 3D geometric modeling technology and realistic graphics generation technology, the finite element structural analysis program system for static and dynamic analysis, sensitivity analysis and optimization design of structures came into being. The application of msc.dytran and other analysis software in packaging design can produce a variety of visual effects, more vividly and vividly show the structure and performance of the designed equipment, so as to achieve the effect of simulation o

establishment of simulation model

establishment of medical case model with CAD Modeling Software Solidworks. It includes outer packing box, buffer foam system and internal fixation system (this article takes the inner glass ampoule as an example). Because msc.patran can be seamlessly integrated with Solidworks, its pre-processing and post-processing functions are powerful. It can identify CAD model features, and automatically perform lattice division and local lattice transition. In this way, the geometric model of the medical box is transformed into a problem abstract model for simulation analysis (see Figure 1)

1. lattice division

tetrahedral elements with 10 nodes are used for lattice division. Each unit has 3 degrees of freedom. See table I for the number of nodes and cells

Table 1 node number and unit number of the medical case model

2. material and properties

the material of the outer packing case is a blend modified polyethylene resin, and its property parameters are: yield strength 18.67mpa, density 0.9357kg/m3, elastic modulus 300mpa, Poisson's ratio 0.40

the buffer packaging material in the medical case is foam, and its property parameters are: density 0.08kg/m3, tensile strength 2MPa, elastic modulus 314mpa, Poisson's ratio 0.34

material parameters of glass ampoule: density 2.5kg/m3, failure strength 25MPa, elastic modulus 55gpa, Poisson's ratio 0.25

3. simulation conditions

under the simulated actual combat conditions, the relative height of the medical box dropped by air is 400m, and the aircraft speed is 300km/h. After leaving the aircraft with an umbrella, it falls down under the action of gravity in the vertical direction, and is subject to air resistance in the opposite direction. During falling, with the increase of falling time, the vertical falling speed increases gradually, and the air resistance increases correspondingly. When the air resistance increases to be equal to the total mass of the medical box (with umbrella), the falling speed will not increase, and the medical box will fall at the vertical speed at this time. This speed is called the critical speed (also known as the equilibrium speed), which is calculated to be about 4.85m/s

at the moment of contact with the ground, due to the sudden loss of movement speed, a force acting on the medical box, called landing impact force, is generated. After calculation, the impact force is about 3000kg, which is equivalent to the impact force when the medical box makes a free fall movement from 1 or 2m height and has a rigid impact with the ground. Therefore, we set the simulation conditions as follows: drop, height of 1, 2m, initial speed, there are too many operating sequences in the system of the universal experimental machine, v0=4.85m/s, and it collides rigidly with the ground

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