Application of CAI technology in conceptual design

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Analysis of the application of CAI technology in conceptual design

I. Introduction

there is no doubt that China is a large manufacturing country. However, this once proud "world factory" hat has now become an endorsement for enterprises with meager profits and vicious competition. The reason is very simple: without their own core technology, they can only do other people's wedding clothes. The cruel reality forced entrepreneurs to start thinking about how to have their own "originality" and change made in China into design in China

the design process of products is generally divided into conceptual design stage, detailed design stage and trial production stage. Among them, the time and resources in the conceptual design stage generally account for only 10% - 30%, but it determines 80% of the product manufacturing cost. If considering the cost of product maintenance period, this proportion is even higher. At the same time, because all the main technical directions of the product are determined in the conceptual design stage, the innovation we call mainly occurs in this stage. Traditionally, conceptual design relies on the experience of engineers and technicians, especially experts. This brings great uncertainty to the enterprise, which greatly increases the risk of the enterprise. In recent years, CAI (Computer Aided Innovation) technology, which has been rapidly exhibited in Europe and America, supports the process of innovative conceptual design with scientific and systematic methods, greatly improves the efficiency and quality of conceptual design, and then brings highly competitive products to enterprises

II. Introduction to CAI technology

Chinese enterprises have estimated that the annual output may reach 350000 vehicles. Functions such as automatic gear shifting, zeroing and data query have generally recognized the significance of innovation for enterprises. The CPC Central Committee and the State Council have also made a decision to build an innovative country, taking enhancing the ability of independent innovation as a national strategy. But on the other hand, when it comes to innovation, many people will also have a fear that innovation is to make great inventions that promote history like the "steam engine", or find the next "relativity"; Astronomical scientific research funds should be invested. In fact, among enterprises that focus on products, solving technical problems is innovation! Data shows that three quarters of engineering problems can be solved through the existing knowledge within the enterprise. The following table: the classification table of invention and knowledge field

therefore, the main problem faced by enterprises is whether they can find a practical and effective methodology, structurally analyze problems, fully mobilize existing knowledge, and creatively seek solutions to problems. In fact, as early as the 1940s, altshuller, a scientist of the former Soviet Union, systematically revealed the laws and principles of human innovation activities on the basis of analyzing a large number of patents, thus forming the TRIZ theory (invention problem-solving theory) to guide innovation activities. In view of the advantages formed by the continuous innovation of the military industry of the former Soviet Union, TRIZ theory once became the target of the spy war between the United States and the Soviet Union. After the collapse of the former Soviet Union, with the migration of TRIZ masters to Europe and the United States, TRIZ theory has been more widely spread and applied in the world, and then has also been rapidly developed. At the beginning of this century, the integration of TRIZ theory and computer technology gradually formed CAI technology. Now, CAI technology integrates more modern design methodology and ontology in the field of knowledge engineering. It has become an independent discipline and serves the technological research and development of enterprises

cai technology is positioned to provide effective help for the conceptual design of products by using a variety of technical analysis methods

The core of CAI technology is the modern design methodology system and the knowledge base of problem-solving ideas excavated from a large number of innovative examples. As shown in the figure below:

composition of CAI technology system

III. research on heat dissipation of electronic components by using CAI technology

current electronic products are rich and colorful. Electronic products contain a large number of heating electronic components. With the continuous improvement of electronic products' functions and shrinking volume, the heat dissipation problem of electronic components has become increasingly prominent, among which the heat dissipation problem of integrated circuit chips is a typical representative. Here, we take it as an example to understand the practical application of CAI technology in conceptual design

will bring transcendental changes to China's EPS industry

3.1 problem situation

Moore's law reveals that the scale of transistor integrated circuits will double every 18 to 24 months. Research shows that the power consumption of the new generation of CPU designed by increasing the number of transistors and frequency is bound to increase by 1.33 ~ 1.77 times compared with the previous generation. It is this power law hidden behind Moore's law that forms the fundamental demand for the continuous improvement of the performance of radiator products. In response to this demand, many manufacturers have formed a number of proprietary technologies in the radiator product design. CPU design power consumption table

in order to solve the problem of heat dissipation, we need to review the basic physical principles of heat dissipation. Heat is mainly transmitted through three ways: heat conduction, heat convection and heat radiation

heat conduction. Through the direct contact of objects, heat is transferred from the parts with high temperature to the parts with low temperature. The transmission speed and capacity of heat energy depend on: a. the material of the object; B. The temperature difference between objects. Heat conduction is the most important way of heat dissipation, and it is also one of the core problems that need to be solved by heat dissipation technology

thermal convection. Heat transfers heat from one place in space to another through a flowing medium (gas or liquid). According to different flowing media, it can be divided into gas convection and liquid convection. The main factors affecting thermal convection are: a. the area and height of ventilation holes; B. Temperature difference; C. The higher the height of the ventilation hole, the faster the convection; D. Liquid convection: the heat conduction effect is better, because the liquid is larger than the heat, so the temperature difference is large and the heat conduction is fast

thermal radiation. It is a transfer mode that can achieve heat exchange without any medium (air) and without relying on the collision between molecules and the flow of gas or liquid. The main factors affecting thermal radiation are: a. the material of the heat source, together with the provincial environmental protection department, forms a joint steering group. The smaller the specific heat of the material, the faster the outward radiation energy, and vice versa. B. The color of the surface. Generally speaking, the absorption and release rate of radiant energy on the surface of bright objects is slow, while the absorption and release rate of radiant energy on the surface of dark objects is faster. In ordinary application environment, compared with heat conduction and heat convection, heat radiation plays a negligible role in heat dissipation, so this factor is generally not considered in radiator design

three common ways of heat transfer

the above figure shows the application forms of three heat transfer methods in radiators. It belongs to heat conduction: it is transmitted from the heat source to the heat sink and inside the heat sink. Convection: heat is transferred to the surrounding space by the heat sink, and then it is dissipated by the convection formed by the combination of fan and heat sink. Heat conduction and convection are the main ways of heat dissipation. Most of the heat generated by the heat source is taken away by the convection formed by the fan after being transferred to the heat sink, and the effect of heat radiation can be ignored

in order to ensure good heat dissipation performance, the radiator design should meet the requirements of the above three heat transfer ways. Then the thermal conductivity and specific heat value of the material; Overall thermal resistance and wind resistance of radiator; The air volume and pressure of the fan have become the core of the design

3.1.1 analyze the problem

the current mainstream radiators mostly adopt the design of heat sink + fan. The advantage of this scheme is that the price is relatively low and the installation is simple; But at the same time, there are also problems such as large occupation of space and noise. In order to solve these problems creatively, we first use CAI system to build the functional model of this technical system. As shown in the following figure:

functional model of electronic component heat dissipation technology system

A) we can see that the components in the current technology system include: heating electronic components, heat conduction pads, heat sinks, fans, air, PCB boards, etc. The heat generated by electronic components is mainly carried away by the air flow brought by the fan after being transmitted to the heat sink through the heat conduction pad

b) through such a functional model, we can more easily find various functional links to be improved. For example, how to enhance the ability of the fan to stir the air? How to enhance the efficiency of air flow and heat carrying? How to enhance the heat transfer efficiency of the heat sink? How to enhance the heat conduction efficiency of the heat conduction pad? These are also the directions for further problem solving

c) with such a function diagram, combined with the principle of value engineering, we can analyze the value of each component in the system. The analysis shows that the ideality index of heat conduction pad is the lowest. This suggests that when we improve this system, we should first consider improving the performance of the heat conduction pad. As shown in the following figure:

value analysis of components

with a clear problem-solving direction, we can carry out in-depth analysis for the specific problem-solving direction. In the process of analysis, the multi screen analysis method provided by TRIZ theory is mainly used. This is a systematic thinking method

system thinking - multi screen analysis method

people have a strong thinking inertia, which causes us to look at problems from the perspective of things. TRIZ theory suggests that we should see the past and future of the problem; Also see the supersystems and subsystems of the problem

let's take "the conduction efficiency of heat conduction pad is insufficient, how to enhance it?" Take multi screen thinking as an example to analyze. Multi screen analysis of the problem of "how to enhance the conduction efficiency of the heat conduction pad"

3.1.2 solving the problem

the above tables ① ~ ④ are the solution ideas obtained after further analysis of the insufficient function of the heat conduction pad. In view of these deep problem-solving directions, we apply computer aided innovation (CAI) system to seek specific solutions. There are two main methods to find solutions: one is to find heuristic solutions in the knowledge base of CAI system, and the other is to solve them according to the contradiction resolution principle provided by TRIZ theory. We apply these two methods one by one

because the CAI system is loaded with a practical knowledge base that is condensed from the analysis and collation of a large number of patents, we can look for it. Traditional knowledge retrieval is generally based on keywords. That is, we input keywords, and the information system gives the query results through keyword matching. At present, with the rapid development of knowledge engineering and artificial intelligence, ontology has become a powerful tool for knowledge sharing. The core of ontology is to establish the relationship between various conceptual ontologies. For example, water is a kind of liquid, that is, liquid is the epistatic relationship of water; Groundwater is a kind of water, that is, groundwater is the subordinate relationship of water; Oil is also a liquid, and water and oil are brothers. In this way, through the organization of ontology, the network relationship between knowledge is built, which creates conditions for us to realize the intelligent capture of knowledge. For example, when we search "purified water", the traditional search engine will search the results in the form of keywords; Through the knowledge network of ontology, CAI technology has intelligently captured relevant solutions for us, such as "purified water", "purified liquid", "purified groundwater", "clean water", "clean alkaline aqueous solution", which has greatly expanded our thinking in closely related fields

here, we search "cooling element" and get a series of solutions

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