Dissertation
Dissertation > Agricultural Sciences > Agricultural Engineering > Agricultural machinery and implements > Initial agricultural product processing machinery > Peeling machine

Broken walnut shell force testing and virtual prototype design of the main components of walnut sheller

Author LvPengXiang
Tutor YangXiaoJing
School Kunming University of Science and Technology
Course Agricultural Mechanization Engineering
Keywords walnut broken shells virtual prototype shelling machine UG ANSYS ADAMS
CLC S226.4
Type Master's thesis
Year 2011
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The walnut processing has very important significance on promoting the healthy development of Walnut industry. With the increasing demand for walnuts both at home and abroad, it will be inevitable to raise the level of mechanized operations of the walnut rind. In the course of processing walnuts, the first problem which needs to be solved is to break the shell. This paper presents the walnut shell-breaking test, applies the virtual prototyping technology to the development of the walnut peeling machine, and conducts the virtual prototype design for the main components of the walnut peeling machine.The virtual prototype technology is a computer-aided design technology in virtual environment for a simulation analysis of the computer digital product model. It is a collection of design, modeling and simulation. After producing various analysis models and making the mechanics, dynamics and kinematics analysis of the whole model, the design may be optimized or improved according to the results of the analysis to enhance the design success rate. The use of virtual prototyping technology for the walnut shelling machine helps to promote the application of the modern design methods in agricultural machinery designs, in order to raise the design level of agricultural machinery and shorten the product development cycle.The thesis designs the walnut shell-breaking test devices and related hardware and software respectively according to the function of shell-breaking force measuring device, including the system design, the hardware design, the software design, the design of the mechanical part of the system. The stepping motor driver circuit and data acquisition circuit is designed, and the related software is designed to control the devices. The design and control of the experimental device will be used in the walnut extrusion shell-breaking experiment to detect the size and changing process of the force.By using the designed experimental device for walnut extrusion breaking shell experiment and analyzing the mechanical performance of walnut extrusion breaking shell, the best forced location to break the walnut shell can be found, and the force displacement curve of the walnut breaking shell can be measured. By analyzing the force of breaking the walnut shell, we can know that when the given force location on the walnut is different, the force size of the walnut breaking is also different. The force location of the small breakage force affects the force extending along the short axis direction and the edge direction, and the force which extends along the long axis direction of the walnut can generate a bigger crushing force than the one that is generated by the delay the direction of the edges of the walnut. At the same time, using the statistical analysis software is to establish the linear equations on the basis of the relations between the walnut dimensions and the force imposed in the corresponding position of the walnut. The neural network model can be formed by using Matlab, and it can be applied to predict the size of the force required to break the shell through the walnut size, weight and cortical thickness of the walnut.A finite element model of the walnut is established by ANSYS, finite element analysis software. The theoretical basis of breaking the shell of the walnut is provided through the finite element analysis of the brittle material of the walnut, using different ways of loading and analyzing the distribution of stress and strain.The thesis analyses the necessity of the guiding device of the walnut sheller, uses the modeling software UG to design a three-dimensional model of the walnut guiding device, carries on the movement analysis of the guide device with ADAMS software, and establishes some basic parameters, such as the angle and the roller rotary speed of the first and second grade guiding groove of the guide device.The thesis summarizes the working principle of the existing walnut shell device, and carries on the overall design of the walnut shelling machine and the structure design of relevant parts, as well as the virtual design for the shelling devices of the walnut shelling machine.Researches in this thesis reveal that the virtual design technology of the walnut shelling machine gives designers a new way to design and development products. It is feasible to apply the virtual prototype technology to the researches and analyses of the walnut shelling machine, which provides a certain methods, basis and referential experiences for further researches and development of the Walnut shelling machine.

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