The Military-industrial Scientific Research System of the Academic Master Chapter 178

Chapter 178 Seiko Plan (two-in-one)

 The person who asked the question was Yao Mengna.

She just felt like she was back to that night when she just met Chang Haonan, when he explained with a flat face why the CFD method could not be used to simulate the vibration problem of straight wings.

Yao Mengna once thought that after such a long period of hard work, at least she would not encounter such embarrassing scenes again.

 But apparently she still slightly overestimated herself.

 When the subject was extended to another field, the distance between the two seemed to be suddenly widened again.

“It really doesn't work using traditional methods.”

Chang Haonan rotated the blackboard 180° to the other side.

 In fact, he had only just sorted out his ideas about using the discrete element method to numerically simulate soft abrasives, and had tried it out through the system.

[Based on discrete element theory, establish a three-dimensional model of abrasive particles, set the size, shape, concentration and density of the model, consider the coupling effect between fluid and abrasive particles, and establish abrasive particles and abrasive particles, abrasive particles and fluid, abrasive particles The contact model with the inner wall surface simulates the force and movement of abrasive particles in the fluid, predicts the movement rules of discrete phase abrasive particles, analyzes the removal mechanism of workpiece material by abrasive particles during abrasive flow polishing, and predicts the effect of abrasive flow polishing...]

Although the discrete element method has been created in the 1970s, the attention it has received so far is basically limited to the field of geotechnical engineering, and is far less widely used than the continuous element method.

 The result was naturally a success.

　　【Consumption of science and technology points for improving the project: 25 points, 250 points for directly giving project results. Are you sure to carry out the research project: Soft abrasive polishing and material surface removal mechanism based on discrete element method? 】

 This time, Chang Haonan did not hesitate for too long and chose to confirm.

On the one hand, this is not an area that he is good at, and more importantly, due to the technical zero principle that triggered quality problems, not only the production of the turbojet 14B, but also the turbojet 14A has been temporarily stopped. Now he is preparing to The four batch 00 J-8Cs delivered to the troops for trial have already started work in the workshop of Factory 112. No one wants to see the completed airframe unable to be delivered because it has to wait for the engine.

On the other hand, the control theory paper published on IEEETransactionsonAutomaticControl allowed him to directly obtain up to 100 scientific research points and 2500 theoretical experience points, so there is no harm in splurging on the points.

 In an instant, a huge amount of knowledge and experience poured into my mind.

Even though he had had this experience many times, he was still fascinated by the feeling of being filled up.

Chang Haonan took a deep breath, raised his hand to gently support his swollen head, and continued as if nothing happened:

“As we all know, whether it is the finite element method or the finite volume method, an important basic assumption is that the dielectric material under study is in a continuous state.”

"Under this assumption, the physical properties of materials can be expressed by continuous functions. These functions that express physical properties are usually called physical equations. By combining the physical equations of the material, the equilibrium equation of the problem, the boundary conditions and the initial conditions, we can Obtain the governing equations of the problem and obtain numerical solutions under specific conditions.”

“However, this type of numerical method has great problems when dealing with bulk materials composed of a large number of solid particles, because each particle in the granular material moves independently, which means that each unit node is likely to undergo large deformations. and displacement.”

“But we can completely change the perspective and focus on the detailed description of the contact behavior between particle objects, between particles and boundary models, and the overall balance relationship, that is, discrete element thinking.”

“Relate the contact behavior between objects with the momentum balance equation of the system, establish a differential equation of motion for each particle unit, and the motion equations of all particles describe the overall motion law of the discrete system.”

"The main research process, I currently judge, can be divided into four steps. The first is to use mathematical language to describe the surface shape, movement and wear of the boundary model, and the second is to make judgments on the contact between the particles and the complex boundary model..."

Chang Haonan talked about some basic theories for about twenty minutes, and then found that most of the people below looked at him with clear eyes.

 Fortunately, there are still a few younger engineers, and Yao Mengna is thinking seriously, and it seems that she understands at least part of it.

that's enough.

Similar to the situation at Institute 601, there are not a few people who need to cooperate with him in numerical simulation work. More people still have to be responsible for specific equipment development work, that is, to actually design and manufacture an adaptive software. The abrasive grinder comes out.

“As for the issue of discrete element simulation, interested comrades can talk to me in detail after the meeting. I probably need 3-4 people to help me with the programming and numerical analysis process.”

“As for the remaining machine tool design part, I think we may need to find some external assistance.”

After all, the main business of Factory 410 is to manufacture aerospace engines rather than machine tools. It would be okay for them to make some technical improvements, but it would be a bit too difficult to build a new grinding equipment from scratch.

 “This is not difficult.”

Zhong Shihong, who saw the dawn of a solution to the problem, instantly became energetic:

“Shengjing No. 1 Machine Tool Factory has always been a cooperative brother with us. They should be more experienced in this area. In particular, the development of abrasives and control systems have been completed by regular workers, and the rest is purely mechanical.”

 “As for the specific method of cooperation...”

Zhong Shihong lowered his head and thought for a while:

"I think the cooperation between the two factories is not enough. If this equipment can be developed according to Chang Gong's ideas, it will be a huge encouragement and promotion for the overall development of our country's manufacturing industry. It just so happens that it is the end of the year. so…"

“My opinion is to urgently apply for a project from above, called the 'Precision Works Plan'. The goal is to systematically improve the production and manufacturing levels of various manufacturing plants in our aviation industry system!”

 Obviously, Zhong Shihong also has some ambitions hidden deep in his heart.

For him, even if the main person to complete this project can only be Chang Haonan, as the leading initiator and the director of the technical department of the 410 Factory, as long as it can be successful, the benefits will definitely be indispensable.

From a larger perspective, if this new finishing method can be quickly promoted, it can also solve the urgent needs of many brother units.

Although the original intention of proposing this idea was just to polish the inner wall of the air film hole, its application range is obviously very wide.

 Even if we only consider the field of aviation manufacturing, there are a large number of variable-diameter pipe parts, such as fuel and oil pipelines, fuel injectors, air guide holes, etc. The production efficiency and yield rate of each type are long-standing problems.

 “Very good, then... let's do it.”

Chang Haonan has already experienced the benefits of doing this kind of project before.

Funds and manpower are sufficient, and various resources applied for are basically given priority to ensure a green light all the way.

 More importantly, the personnel subsidies are very generous.

Even Factory 182 can give out a bonus of 20,000 yuan at a time, let alone Factory 410.

 He ​​considers himself not a person with strong material desires, but who wouldn't want to earn more money while completing projects.

For such an urgent matter, it is of course impossible to wait until the project is approved before starting construction. So the next day, before Zhong Shihong started writing the application report, several key personnel from Shengjing No. 1 Machine Tool Factory had already arrived at Factory 410.

 The team was led by a fat, middle-aged engineer named Han Youde who looked to be in his forties and looked elegant.

After hearing Chang Haonan's complete idea about the new grinding equipment, he was stunned for about a second.

 Then he spoke a somewhat obscure foreign language phrase almost subconsciously.

Chang Haonan didn't understand, but it wasn't English anyway.

 Fortunately, the other party reacted quickly, picked up a sharpened pencil from the table, and started drawing directly on a piece of drawing paper.

Compared to Chang Haonan of the abstract school, Han Youde's painting skills are obviously much better. Although it is a schematic diagram that does not even use a ruler or compass, it is still horizontally, vertically, and very regular.

"often…"

 “Chang Haonan.”

 Someone gave a just-in-time reminder.

“I came into contact with the equipment described by Comrade Chang Haonan more than ten years ago when I was studying in East Germany. Directly translated from German, it is called fluid abrasive processing, or abrasive flow processing.”

While Han Youde was speaking, he did not stop moving his hands. In a few minutes, the general outline of a machine appeared on the paper.

“The principle of this grinding method is not difficult, and the equipment is also very simple. Except that the fixture needs to be customized according to the parts to be processed, I can complete the design of other parts in about four to five days.”

Master Chang Haonan himself heard more than one gasp—

ˆ also includes his own.

"So fast?"

 Similar questions are usually asked by others to confirm to him, but now the situation has changed and it is his turn to ask.

 The main reason is that this efficiency is indeed a bit too exaggerated.

"Because this abrasive flow processing method is actually not a new technology. As far as the machine tool itself is concerned, it is almost the simplest type. There are no high-speed rotating parts or high-pressure parts. It does not even require any design. Even if I am in If you copy the equipment that East Germany saw, it will not fall behind in another twenty years.”

Han Youde threw the pencil on the table:

“The real difficulty of this process lies in the design of the abrasive ratio and control system. Such a good idea has never been widely used abroad. There are very few people in China who even know about it. This is why.”

"Due to the inherent defects of soft abrasives, they have to be specially designed for almost every different workpiece. The machine I saw in East Germany was used to process a high-pressure common rail pipe. We can look at the equipment casually, but the abrasives The recipe is top secret, and it is said that it took them almost two years to find the optimal solution for that part.”

 “It doesn't matter, this part of the job is what Chang Gong is best at.”

　　Someone next to me interrupted.

“Looking at it this way, I think this craft is quite interesting.”

Hearing the words of the people around him, Han Youde raised his head and glanced at Chang Haonan next to him.

But he didn't say anything, he just nodded calmly:

“Anyway, it's not easy to come up with this idea without seeing abrasive flow equipment before.”

 “Let's get started.”

Although the project entities are 410 Factory and Shengjing No. 1 Machine Tool Factory, these two companies obviously do not have enough conditions for Chang Haonan to do numerical simulation.

 Fortunately, the current focus of work on the 601 side has been shifted to Project 11. The computing center is mainly responsible for digitizing the Su-27 design data together with Russian experts. There is no large-scale calculation work to be done for the time being.

So after going round and round, I finally went back to No. 601 to borrow a few workstations and three people including Lin Shikuan.

Although the discrete element method is quite different from the continuous finite element method in terms of theoretical basis and calculation ideas, numerical simulation is an ever-changing thing after all. Several people who already have the foundation did not let Chang Haonan spend too much chalk. and tongue, you can roughly understand the work that each of them has to accomplish.

Especially for Lin Shikuan, it has been like a sudden enlightenment in recent months, and he has made rapid progress.

 When we first met, he didn't even understand how to digitize paper materials, but now he can draw inferences and put forward some of his own understanding.

After receiving her mission, Yao Mengna did not leave immediately, but approached Chang Haonan:

“Junior brother, I think this contact judgment problem only requires a neighbor search and then an intersection test. It doesn't seem to take as long as you arranged?”

“If we talk about the matter, it is indeed true. The air film hole on the turbojet 14 is a circular hole, the flow path is very simple, the grid construction and the selection of boundary conditions are easy, and the calculation amount is not large.”

Chang Haonan has opened the workstation at this time and is verifying the algorithm according to the ideas he has written long ago:

 “But I have some further ideas.”

"The Korean worker at the machine tool factory was right when he said that soft abrasives need to be designed individually for each workpiece. This is not difficult for us to achieve. However, most corporate engineers have average theoretical knowledge and we cannot expect them to learn it from scratch. Discrete Element Fundamentals and Computer Programming.”

"So, I plan to develop a three-dimensional particle discrete element simulation software that is relatively easy to use based on the ideas I used when doing CFD. This process has great application potential. Only by lowering the learning threshold can more manufacturers use it. Benefit.”

Hearing this answer, Yao Mengna's red lips moved slightly, but she couldn't make any sound. She just stared at Chang Haonan's profile for a while.

 I don't know when she started, but she liked to peek at each other from this angle.

Obviously he is his junior disciple, but not only does he have a stronger scientific research ability, but he even thinks about things from a different perspective.

"well…"

 After a short while, Yao Mengna sighed softly, turned around and left with a complicated expression.

 (End of this chapter)

Chapter end