If you have done mechanical design for several years or more than ten years, then read this article carefully, the experience summary you want to write is already here.
Mechanical design (machine design), according to the requirements of use, conceives, analyzes and calculates the working principle, structure, movement mode, force and energy transmission mode, material, shape and size of each part, lubrication method, etc. of the machine and converts them into A specific description is used as a manufacturing basis for the working process.
Mechanical design is an important part of mechanical engineering, the first step in mechanical production, and the most important factor determining mechanical performance.
The goal of mechanical design is to design the best machinery under various limited conditions (such as materials, processing capabilities, theoretical knowledge and calculation methods, etc.), that is, to make optimal designs.
Optimal design needs to comprehensively consider many requirements, generally including: the best working performance, the lowest manufacturing cost, the smallest size and weight, the most reliable in use, the lowest consumption and the least environmental pollution. These requirements are often contradictory, and their relative importance varies with the type and application of the machinery. The task of the designer is to weigh the importance according to the specific situation and make overall plans so that the designed machinery has the best comprehensive technical and economic effect.
In the past, the optimization of the design mainly relied on the designer's knowledge, experience and foresight. With the development of new disciplines such as the basic theory of mechanical engineering, value engineering, and system analysis, the accumulation of technical and economic data for manufacturing and use, and the popularization and application of computers, optimization gradually abandons subjective judgments and relies on scientific calculations. (Editor's Note: "Old" engineers should pay attention, if they do not make progress, they will be eliminated)
The design of various industrial machinery, especially the mechanical design of the whole and the whole system, must be attached to various related industrial technologies and it is difficult to form an independent discipline. Therefore, professional mechanical design subdisciplines such as agricultural machinery design, mining machinery design, pump design, compressor design, steam turbine design, internal combustion engine design and machine tool design have emerged. (Editor's Note: The old saying goes that "interlacing is like a mountain", but now it is "going together like a mountain". It is also a mechanical design. You are an expert in this field. If you change to another field, you may be a layman)
1
Design Classification
Mechanical design can be divided into three categories: new design, inherited design and variant design.
1. New design
Apply mature science and technology or new technologies that have been proven to be feasible through experiments to design new types of machinery that have never been seen before.
2. Inheritance design
According to the use experience and technological development, the existing machinery is designed and updated to improve its performance, reduce its manufacturing cost or reduce its operating cost.
3. Variant design
In order to meet the new needs, some modifications or additions and deletions are made to the existing machinery to develop variant products different from the standard type.
2
main process
1. Formulate design tasks according to customer needs, market needs and new scientific research results.
2. Preliminary design. Including determining the working principle and basic structural form of the machine, carrying out motion design, structural design and drawing a preliminary general drawing and preliminary review.
3. Technical design. Including modification of the design (according to the opinion of the first review), drawing of all parts and new general drawings and the second review.
4. Work drawing design. Including the final modification (according to the opinions of the second review), drawing of all working drawings (such as parts drawings, component assembly drawings and general assembly drawings, etc.), and formulating all technical documents (such as parts list, list of wearing parts, instructions for use, etc.).
5. Finalize the design. Machinery for batch or mass production. For mechanical design with relatively simple design tasks (such as new design of simple machinery, inheritance design or variant design of general machinery, etc.), the preliminary design procedure can be omitted.
3
design phase
The quality of a machine basically depends on the design quality. The role played by the manufacturing process on the quality of the machine is essentially to achieve the quality specified at the time of design. Therefore, the design stage of the machine is the key to determine whether the machine is good or bad.
The design process discussed only refers to the technical design process in a narrow sense. It is a creative work process, but also a work that uses as much as possible the existing successful experience. Only by combining inheritance and innovation well can we design high-quality machines. As a complete machine, it is a complex system. To improve the design quality, there must be a scientific design procedure. Although it is impossible to list a unique program that is effective in every situation, based on people's long-term experience in designing machines, the design program of a machine can basically be as shown in the table.
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Each stage is briefly described below.
(1) Planning
In the planning stage, adequate investigation, research and analysis should be done on the demand of the designed machine (Editor's Note: such as carefully studying the customer's demand and providing relevant information, repeatedly communicating with the customer to clarify the customer's ideas and intentions, etc.), through Analysis, to further clarify the functions that the machine should have, and put forward the constraints determined by the environment, economy, processing and time limit for future decision-making. On this basis, clearly write out the overall requirements and details of the design task, and finally form a design task book as a summary of this stage.
The design task book should generally include: the function of the machine, the estimation of economy and environmental protection, the rough estimation of manufacturing requirements, the basic use requirements, and the expected time limit for completing the design task, etc. At this time, generally only a reasonable range can be given for these requirements and conditions, rather than exact figures. For example, it can be determined by the requirements that must be met, the minimum requirements, and the requirements that are expected to be achieved.
(2) Scheme design
According to different working principles, a variety of specific schemes for implementing agencies can be drawn up. For example, in terms of thread cutting, the workpiece can only be rotated and the tool can be moved linearly to cut the thread (such as cutting the thread on an ordinary lathe), or the workpiece can be kept still while the tool rotates and moves to cut the thread ( Such as processing threads with dies). That is to say, even for the same working principle, there may be several different structural solutions.
The scheme of the prime mover part (editor's note: power part) can of course also have many choices. Due to the universality of power supply and the development of electric drive technology, it can be said that the vast majority of stationary machinery now prefers the electric motor as the prime mover. Thermal prime movers are mainly used in transport aircraft, construction machinery or agricultural machinery. Even if the motor is used as the prime mover, there are also options for AC and DC, high speed and low speed, etc.
The scheme of the transmission part is more complex and diverse. For the same transmission task, it can be completed by a variety of mechanisms and combinations of different mechanisms. Therefore, if IV is used to represent the number of possible solutions of the prime mover part, and N2 and N3 represent the possible numbers of solutions of the transmission part and the execution part respectively, then the number of possible solutions IV of the machine as a whole is Ni×N2×N3. (Editor's Note: Effective solutions are only functionally feasible, and then screened from technical and economic perspectives)
The above is only discussed in terms of the three main parts that make up the machine. Sometimes it is necessary to consider the configuration of auxiliary systems.
Among so many solutions, only a few are technically feasible. These several feasible schemes should be comprehensively evaluated from the aspects of technology, economy and environmental protection. There are many evaluation methods, and the economic evaluation is taken as an example to illustrate briefly.
When evaluating in terms of economy, it is necessary to consider not only the economy of design and manufacture, but also the economy of use. If the structural scheme of the machine is more complicated, its design and manufacturing cost will be relatively increased, but its functions will be more complete, and its productivity will be higher, so the use economy is also better. Conversely, for a machine with a relatively simple structure and insufficient functions, although the design and manufacturing costs are low, the operating cost will increase. When evaluating the design and manufacturing economy of structural schemes, it can also be expressed by the cost of unit efficacy. For example, the cost per unit output power, the cost of a single product, etc.
When evaluating the machine, it is necessary to analyze the reliability of the machine, and take the reliability as an evaluation index. From a reliability point of view, it is often unwise to blindly pursue complex structures. Generally speaking, the more complex the system, the lower the reliability of the system. In order to improve the reliability of the complex system, it is necessary to increase the parallel backup system, which will inevitably increase the cost of the machine.
Environmental protection is also an important aspect that must be carefully considered in the design. Technical solutions that have adverse effects on the environment must be analyzed in detail and technically mature solutions must be proposed.
Through the program evaluation, the final decision is made to determine a schematic diagram or a schematic diagram of mechanism movement for the next step of technical design.
In the scheme design stage, the relationship between reference and innovation must be properly handled. The successful precedents of similar machines should be used for reference, and the original weak links and parts that do not meet the requirements of existing tasks should be improved or fundamentally changed. It is necessary to actively innovate and oppose conservatism and copying the original design, and also oppose the two wrong tendencies of blindly pursuing innovation and discarding reasonable original experience. (Editor's Note: The key to learning from is to find out the shortcomings of the original calculation)
(3) Technical design
The goal of the technical design phase is to produce a general assembly sketch and a component assembly sketch. Determine the shape and basic size of each component and its parts through sketch design, including the connection between parts, the shape and basic size of parts and components. Finally, draw the working drawings, component assembly drawings and general assembly drawings of the parts.
In order to determine the basic size of the main parts, the following work must be done:
(1) Kinematics design of the machine.
According to the determined structural scheme, determine the parameters of the original moving part (power, rotational speed, linear speed, etc.). Then do kinematic calculations to determine the motion parameters (speed, speed, acceleration, etc.) of each moving component.
(2) Dynamic calculation of the machine.
Combined with the structure and motion parameters of each part, the magnitude and characteristics of the load on each main part are calculated. The load obtained at this time is only the nominal (or nominal) load acting on the part because the part has not been designed.
(3) The working capacity design of the parts.
The preliminary design of parts and components can be done if the size and characteristics of the nominal load on the main parts are known. The working capacity criteria on which the design is based must be reasonably drawn up with reference to the general failure conditions, working characteristics, and environmental conditions of parts and components. Generally, there are criteria such as strength, stiffness, vibration stability, and service life. By calculation or analogy, the basic dimensions of parts and components can be determined.
(4) Design of component assembly sketches and general assembly sketches.
According to the basic dimensions of the main parts and components that have been determined, the component assembly sketch and the general assembly sketch are designed. The outline and dimensions of all parts need to be structurally designed on the sketch. In this step, it is necessary to coordinate the structure and size of each part well, and fully consider the structural manufacturability of the designed parts and components, so that all parts have the most reasonable configuration.
(5) Checking of main parts.
For some parts, in step (3) above, due to the undecided specific structure, it is difficult to carry out detailed calculation of working capacity, so only preliminary calculation and design can be done. After the component assembly sketch and the general assembly sketch are drawn, the structure and size of all parts are known, and the relationship between adjacent parts is also known. Only at this time can the load acting on the part be determined more accurately, and various detailed factors that affect the working ability of the part can be determined. Only under this condition, it is possible and necessary to carry out accurate check calculations for some important parts or parts with complex shapes and stress conditions. According to the results of the check, the structure and size of the parts are repeatedly modified until they are satisfied.
In each step of technical design, the optimization design technology developed in the past 30 to 40 years has increasingly shown its ability to optimize the selection of structural parameters. Some new numerical calculation methods, such as finite element method, can obtain excellent approximate quantitative calculation results for problems that were previously difficult to quantitatively calculate. For a small number of very important, complex and expensive parts, the model test method must be used to design when necessary, that is, the model is manufactured according to the preliminary design drawings, and the structural weak parts or redundant sections are found through tests. Size, according to which to strengthen or reduce to modify the original design, and finally reach the level of perfection. The mechanical reliability theory is used in the technical design stage. From the perspective of reliability, it can evaluate whether the designed parts and component structures and their parameters meet the reliability requirements, and put forward suggestions for improving the design, thereby further improving the design quality of the machine. . The above-mentioned new design methods and concepts should be applied and promoted in the design, so that they can be developed accordingly.
After the sketch design is completed, the working drawing of the part can be designed according to the basic size of the part that has been determined in the sketch. At this point, there are still a large number of structural details of the parts to be refined and determined. When designing working drawings, it is necessary to fully consider the processing and assembly process of parts, the inspection requirements and implementation methods of parts during and after processing. If some detailed arrangements have a worthy impact on the working ability of the parts, it is necessary to go back to recheck the working ability. Finally, draw the working drawings of all parts except standard parts.
Redraw the component assembly drawing and general assembly drawing according to the structure and size on the finalized part working drawing. Through this work, dimensional and structural errors that may be hidden in the part work drawing can be checked out. People call this work colloquially assembly on paper. (Editor's Note: Now using 3D software design, it is very convenient to modify, so the steps of technical design can be crossed, but it is indispensable. Of course, some checks can use the software's own functions.)
(4) Compilation of technical documents
There are many types of technical documents, and the commonly used ones include machine design and calculation instructions, operating instructions, and standard parts list (BOM).
When compiling the design calculation specification, it shall include all conclusive contents of scheme selection and technical design.
When compiling the machine instruction manual for users, the range of performance parameters, operation methods, daily maintenance and simple repair methods, catalog of spare parts, etc. of the machine should be introduced to the users.
Other technical documents, such as the inspection certificate, the list of purchased parts, and acceptance conditions, etc., shall be prepared separately as needed.
(5) Application of computer in mechanical design
With the development of computer technology, computers have been widely used in mechanical design, and many high-efficiency design and analysis software have emerged. These softwares can be used to compare multiple schemes in the design stage, and can accurately analyze the structural strength, stiffness and dynamic characteristics of different schemes including large and complex schemes. At the same time, it is also possible to build a virtual prototype on the computer, and use the virtual prototype simulation to verify the design, so as to fully evaluate the feasibility of the design in the design stage. It can be said that the promotion and use of computer technology in mechanical design has and is changing the process of mechanical design, and its advantages in improving design quality and efficiency are difficult to predict.
The above briefly introduces the design procedure of the machine. Broadly speaking, in the manufacturing process of the machine, it is possible to modify the design due to process reasons at any time. If modification is required, certain approval procedures should be followed (Editor's Note: Engineering Change, Engineering Chan
ge, EC). After the machine leaves the factory, follow-up investigations should be carried out in a planned way; in addition, users will also report problems to the manufacturing or design department during use. Based on these information, the design department may modify or even remodel the original design after analysis. These tasks, while broadly part of the design process, are another level of problem. As a designer, one should have a strong sense of social responsibility, extend one's vision of work to the whole process of manufacture, use and even scrapping, and improve the design repeatedly, so as to continuously improve the quality of the machine and better meet the needs of production and life.
stage description
(1) Planning stage
After the project tasks are issued, the planning stage is only a preparatory stage. At this point, there is only a vague idea of the machine to be designed.
(2) Scheme design stage
This stage plays a key role in the success or failure of the design. At this stage, it also fully demonstrates the characteristics of multiple solutions (schemes) in the design work.
The function analysis of the machine is to conduct a comprehensive analysis of the requirements, minimum requirements and expected requirements of the machine functions proposed in the design task book, that is, whether these functions can be realized, whether there are contradictions among multiple functions, and whether they can be replaced by each other. Finally, the functional parameters are determined as the basis for further design. In this step, possible conflicts between needs and possibilities, ideals and reality, development goals and current goals should be properly handled.
After the functional parameters are determined, possible solutions can be proposed, that is, possible solutions can be proposed. When looking for a solution, it can be discussed separately according to the driving part, transmission part and execution part. It is more common to start the discussion with the operational part first.
When discussing the execution part of the machine, it is first about the choice of working principle (editor's note: that is, the method of implementation). For example, when designing a machine for manufacturing screws, its working principle can be either the method of turning threads with a turning tool on a cylindrical blank, or the method of rolling threads with a rolling die on a cylindrical blank. This presents two different operating principles. The working principles are different, and of course the machines designed will be fundamentally different. In particular, it should be emphasized that new working principles must be continuously researched and developed. This is an important way to design technology development.
4
design steps
Before the design begins, the design tasks are formulated.
When the design task is more complicated, three-stage design is generally adopted, namely preliminary design, technical design and working drawing design; when the task is relatively simple, such as the new design of simple machinery, the inheritance design or variant design of general machinery, the design will be designed to the depth of technical design at the beginning, and the working drawing design will be done after review, modification and approval, which becomes a two-stage design.
In the preliminary design stage of the three-stage design, the main steps of the design are: determining the working principle and basic structural type, motion design, designing main parts and components, drawing a preliminary general drawing, and reviewing the preliminary design.
In the technical design stage, the main steps are: modify the design according to the review opinions, design all parts and components, draw a new general drawing, and review the technical design.
In the stage of working drawing design, modify the design according to the review opinions, draw all working drawings and formulate all technical documents. For batch or mass-produced products, finalized design is also required.
In each step of the design, it is possible to find that some decisions in the previous steps are unreasonable, which requires turning back to the previous step, revising the unreasonable decisions, and redoing the subsequent design work.
(1) Formulate design tasks
This is the preliminary work of the design. Design tasks are based on user orders, market needs and new scientific research results. The design department uses various technologies and market intelligence, draws up possible plans, compares their pros and cons, discusses with the business department and users, and formulates reasonable design task goals. This is especially important for new designs. Mistakes in mission goals will result in severe economic losses and even total failure.
(2) Determine the working principle and basic structure type
If the design task is not clearly defined, the first step in the design is to determine the overall plan, that is, to determine the working principle to be applied and the corresponding structural type.
For example, to design a high-power marine diesel engine, it is first necessary to determine whether to use a two-stroke, double-acting, crosshead, low-speed diesel engine, or a four-stroke, single-acting, medium-speed diesel engine.
Another example is the crushing machinery designed for coarse crushing of rocks. First, it must be determined whether to use a jaw or gyratory crusher with extrusion and bending as the main crushing action, or a single-rotor or double-rotor impact crusher with impact as the main action.
(3) Motion Design
After the overall plan of the design is determined, then it is necessary to use the knowledge of mechanism to select the appropriate mechanism to obtain the required motion plan. The above-mentioned jaw crusher relies on the swing of its movable jaw to crush the rock entering the crushing cavity by squeezing, bending and splitting, while the swing of the movable jaw can be a simple swing of a double toggle mechanism or a complex swing of a single toggle mechanism. In new designs, it may be necessary to synthesize a new mechanism to obtain the required motion scheme, which is often a difficult task. Therefore, designers generally try to apply the motion schemes proposed by existing and mature mechanisms.
(4) Structural design and preliminary general drawing
After the motion design, the designer starts the structural design, calculates the force, strength, shape, size and weight of the main parts of the machine, and draws sketches of the main parts and components. At this time, if it is found that the originally selected structure is not feasible, the structure must be adjusted or modified. Consideration should also be given to the possibility of overheating, excessive wear or vibration.
In this step, the designer will find contradictions in the shape, size, proportion, etc. of each part by drawing a sketch. To strengthen or improve one aspect may weaken or worsen another. At this time, it is necessary to weigh the importance and coordinate to achieve the best comprehensive effect. (Editor's Note: The essence of design is the process of constantly weighing choices). After the sketch has been revised repeatedly and is deemed initially satisfactory, the preliminary general drawing and estimated cost (cost estimate) can be drawn. The preliminary general drawing is drawn strictly to scale, and sufficient views and sections are selected.
(5) Preliminary review
After the preliminary general drawing is drawn, it is necessary to invite experienced design, manufacture and user personnel of this type of machinery, as well as representatives of the user or entrusted design unit to conduct a preliminary review. If the review results indicate that the design is not applicable (such as too much weight and volume, too high cost, doubts about the reliability of the structure, etc.), the motion design must be re-designed, or even replaced with other working principles and basic structural types. In most cases, some improvements to the design are made.
(6) Technical design
According to the preliminary review comments, the design is modified and all parts and assembly drawings are drawn. Carry out accurate stress analysis on the main parts and components, correct the shape, size and other details of the parts according to the analysis results, and specify the material and heat treatment. Determine the machining accuracy of parts and the assembly conditions of components and final assemblies. Complete lubrication design, electrical design (drive and control). The general drawing is redrawn, and some important and mass-produced machinery sometimes have to make models. Submit the completed technical design for a second review.
(7) Draw working diagram
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After the final modification is made according to the opinions of the second review, formal parts drawings, component assembly drawings and general assembly drawings can be drawn, and technical documents such as parts list, list of vulnerable parts, and user guide can be prepared. The person in charge of the design should pay attention to coordinating the dimensions between the parts, checking the tolerance fit between the coupling parts, and reviewing the strength and rigidity of some parts.
After the part drawing is completed, the drawing check is started, which is a very important job. Carefully proofread drawings can ensure smooth assembly after processing. The most reliable proofreading method is to redraw a general assembly drawing based on the drawn parts drawing (editor's note: draw the designed parts in the computer according to the assembly connection method to draw the general assembly again), and all contradictions will be displayed.
Two tasks need to be carried out while drawing the part drawing: one is the technical review to make the parts easy to process and reduce the manufacturing cost; the other is the standard review to make the structural elements, dimensions, tolerance fit, heat treatment technical conditions, standards and general parts of the parts meet the requirements of the standard.
(8) Trial production and finalized design
For single-piece or small-batch production of machinery, the design drawings completed through the above steps can be put into formal production. For machines produced in batches or in large quantities, prototypes must be trial-produced before formal production, and functional tests and appraisals must be carried out. After passing, batch trial production will be carried out according to the mass production process. Problems that arise during batch trial production may require corresponding modifications to the design before it can become a finalized design that can be used in formal production.
5
Constraints (design criteria)
The design of mechanical parts has many constraints, and the design criteria are the constraints that the design should meet.
(1) Technical performance criteria
Technical performance includes all performance including product function, manufacturing and operating conditions, and refers to both static performance and dynamic performance. For example, the power, efficiency, service life, strength, stiffness, friction resistance, wear performance, vibration stability and thermal characteristics that the product can transmit.
The technical performance criterion means that the relevant technical performance must meet the specified requirements. For example, vibration will generate additional dynamic load and variable stress, especially when its frequency is close to the natural frequency of the mechanical system or parts, resonance will occur, and the amplitude will increase sharply, which may lead to rapid damage to parts or even the entire system. The vibration stability criterion is to limit the relevant vibration parameters of the mechanical system or parts, such as natural frequency, amplitude, noise, etc., within the specified allowable range. Another example is the heat generated when the machine is working, which may cause thermal stress, thermal strain, and even thermal damage. The criterion of thermal characteristics is to limit various related thermal parameters (such as thermal stress, thermal strain, temperature rise, etc.) within the specified range.
(2) Standardization criteria
The main standards related to the design of mechanical products are roughly as follows:
Concept standardization: terms, symbols, measurement units, etc. involved in the design process should meet the standards;
Standardization of physical form: The structural form, size, performance, etc. of parts, raw materials, equipment, and energy sources should be selected according to uniform regulations.
Method standardization: operation methods, measurement methods, test methods, etc. should be implemented in accordance with the corresponding regulations.
The standardization criterion means that all behaviors in the whole process of design must meet the above-mentioned standardization requirements. The published standards related to the design of mechanical parts can be divided into three levels: national standards, industry standards and enterprise standards in terms of application scope. In terms of mandatory use, it can be divided into mandatory and recommended.
(3) Reliability criteria
Reliability: The probability that a product or component can complete the specified function within the expected life under specified conditions of use. The reliability criterion means that the designed product, component or part should meet the specified reliability requirements.
(4) Security Guidelines
Machine safety includes:
Parts safety: refers to the fact that the parts do not occur such as fracture, excessive deformation, excessive wear and loss of stability under the specified external load and within the specified time.
The safety of the whole machine: refers to the requirement that the machine guarantees that there will be no failures under the specified conditions and that the general functions can be realized normally.
Work safety: refers to the protection of operators, ensuring personal safety and physical and mental health, etc.
Environmental safety: refers to the non-pollution and harm to the environment and people around the machine.
6
design methodology
The purpose of design methodology is to elevate design thinking into a rational process, so that design can be carried out according to a certain logic, so that more designers can make good designs. It generally includes the following contents:
(1) Divide the stages of design into very fine steps, making each stage a thought activity with rules to follow and evidence to follow.
(2) Store successful or good designs and establish a design database for reference or adoption in future designs.
(3) Introduce the concept and method of value engineering in the design work, and balance the function and cost of the contradiction in the design to obtain a good use effect.
(4) Use the knowledge of emerging disciplines such as tribology, vibration, fracture mechanics, finite element method, reliability design, optimization design, system engineering and ergonomics in the design to improve the scientific nature of the design and reduce blindness.
(5) Expand the scope of design work, extending forward to market forecast and backward to after-sales service.
(6) Use computer-aided design to reduce design labor, improve design speed and design quality.
7
outlook
In the future, mechanical design will permeate into industries such as semiconductor manufacturing, bioengineering, nanotechnology, and robotics. While making contributions to social development, it will continue to improve itself and further innovate its theory.
(1) To further realize systematization
That is, starting from the system point of view, the mechanical product is regarded as a system or a whole, relying on computer technology to realize the coordination between man, machine and environment. Specifically, it decomposes the total system into several subsystems, adopts various modern design theories and methods, and pursues system optimization as the goal to coordinate the design and matching of each subsystem.
(2) Deepen intelligent design
With the advancement and development of science and technology, more and more factors of intelligence should be considered in design. A large amount of design content can be described by establishing models to describe the behavior of various working conditions of mechanical products, and solving the models can predict the performance of the product, the rationality and optimality of the design. For example, intelligent decision-making systems for various vehicle performance evaluations, gearbox design expert systems, and fault diagnosis systems have been applied in the development and design of new vehicles.
(3) Pay more attention to green thinking
Green design technology is a technology for designing products in their life cycle according to the requirements of environmental protection, highest resource utilization and lowest energy consumption. Designers are required to consider the environmental attributes and basic attributes of products from the whole cycle, and always base their designs on people's physical and mental health and environmental protection. At the same time, the designed products are required to be recyclable and cause minimal damage to the environment.
8
modern design method
1. Professional and modern
Computer software jointly developed by mechanical design and computer professionals can reflect and describe various damage, failure and destruction mechanisms of mechanical products under actual working conditions. It can quantitatively analyze and calculate the dynamic behavior of mechanical parts and machinery, and form a fixed design program. This is a professional modern design method, such as vibration analysis and design, tribology design, thermodynamic heat transfer design, strength, stiffness design, temperature field analysis, etc. These softwares are all developed on the basis of traditional design methods and using computer technology. For example: using Pro/M software to analyze the dynamic characteristics of mechanical devices, and using ANSYS software to analyze stress are good examples in this regard, laying the foundation for accurately judging the reliability of the device and selecting design parameters.
2. Universal Modern
In order to meet the high requirements of mechanical product performance, computer technology is widely used in mechanical design for aided design and system analysis, which is a common modern design method. Common methods include optimization, finite element, reliability, simulation, expert systems, and CAD. These methods are not only for the research of mechanical products, but also have their own scientific theories and methods.
1) Optimized design
Mechanical optimization design is the transplantation and application of optimization technology in the field of mechanical design. Its basic idea is based on the theory of mechanical design.
