With the rapid development of contemporary science and technology and the wide application of computer technology, modern design method is a new interdisciplinary subject developed in related fields. It is the general name of the general knowledge group whose goal is to design products. At present, its contents mainly include: optimization design, reliability design, computer-aided design, industrial art modeling design, virtual design, fatigue design, tertiary design, similar design, modular design, reverse engineering design, dynamic design, finite element method, ergonomics, value engineering, concurrent engineering, artificial neuron calculation method and so on. When they are used in engineering design, computers are generally used as tools for analysis, calculation, synthesis and decision-making. This section takes computer-aided design, optimization design, reliability design, finite element method, industrial art modeling design, design methodology and tertiary design as examples to illustrate the basic contents and characteristics of modern design methods.

1, computer-aided design

Computer aided design. He is a modern design method that introduces computer technology into the design process and uses it to complete operations such as calculation, selection and drawing. Computer, drawing and other peripheral devices constitute the CAD hardware system, while the operating system, language processing system, database management system and application software constitute the CAD software system. Generally speaking, a CAD system is only composed of system hardware and system software, and has the functions of calculation, graphic processing, database, etc., and can comprehensively use these functions to complete the design work. The typical CAD workflow is shown in figure 1-3.

2. Optimize the design

Optimization design is a modern design method that applies the principle of optimization mathematics to engineering design problems and seeks the best design scheme among all feasible schemes.

In the process of engineering optimization design, firstly, the mathematical model of engineering problems is established according to the format specified in the optimization design, and then the appropriate optimization calculation method is selected to solve the mathematical model on the computer, so as to obtain the optimal design scheme of engineering design problems.

In the process of establishing the mathematical model of optimal design, those parameters that affect the choice of design scheme are called design variables; The conditions that design variables should meet are called constraints; The index chosen by the designer to measure the quality of the design scheme and expect to be improved is expressed as a function of design variables, which is called the objective function. Design variables, constraint functions and objective functions constitute the mathematical model of optimization design problems. The optimization design needs to publish the mathematical model and optimization calculation into the computer program, and use the computer to automatically find the optimal solution. Commonly used optimization algorithms are: 0.6 18 method, power method, variable scale method, composite method and penalty function method.

3. Reliability design

Reliability design is a modern design method based on probability theory and mathematical statistics, failure analysis, failure prediction and various reliability tests to ensure product reliability.

The basic content of reliability design is to select the reliability index and its value of the product, allocate the reliability index reasonably, and then design the specified reliability index into the product.

4. Finite element method

Finite element method is a numerical calculation method with computer as a tool. At present, this method can not only be used to solve complex nonlinear and unsteady problems in engineering (such as structural mechanics, fluid mechanics, heat conduction, electromagnetic field, etc.). ), it can also be used to analyze the static and dynamic characteristics of complex structures in engineering design and accurately calculate the stress distribution and deformation of complex parts, thus becoming a favorable analysis tool for calculating the strength and stiffness of complex parts.

5, industrial art modeling design

Industrial art modeling design is a new discipline that combines engineering technology with aesthetic art. On the premise of ensuring the use function of products, he uses artistic means to model industrial products according to aesthetic laws, including structural dimensions, appropriate forms, colors, materials, lines, decorations and interpersonal relationships, so as to design high-quality and beautiful product modeling. The best unity of practicality and beauty is the basic principle of industrial art modeling.

The main contents of this subject include: basic elements of modeling design, basic principles of modeling design, aesthetic rules, color design, ergonomics and so on.

6, reverse engineering design

Reverse engineering is the sum total of a series of working methods and technologies that digest, absorb and improve advanced technologies at home and abroad. It is a method and technology to analyze, dissect and test the existing advanced products through physical or technical data, understand their materials, components, structures, properties and functions, master their technological principles and working mechanisms, and create new products through digestion, imitation, improvement or development. It is a combination of a series of analytical methods and applied technologies, aiming at advanced digestion and absorption technology.