Chapter 506 Just right, a little research

Naturally, it is not easy for most researchers who have just begun to understand the situation of this project to interrupt this discussion about the selection of technical routes.

Only a few people Chang Haonan originally planned to meet with were able to participate in the discussion.

Although several old comrades worked together under the leadership of Academician Shen Hong more than ten years ago, after the die forging press project was suspended, these people were scattered to several different research institutes far apart across the country for various reasons. mechanism.

Although they are still more or less continuing to study heavy-duty hydraulic presses, there is almost no academic exchange between them.

So in fact, they now know no more about each other's research content than Chang Haonan, who met for the first time but had read the materials specifically.

So, before Yan Yongnian could even think of how to speak again, another voice sounded:

"My mentor and I have systematically studied the plate-frame composite structure rack for a period of time in the past few years."

The speaker was a young professor from Central South University of Technology, Han Huiming.

He is only in his early 30s, so of course it is impossible for him to have participated in the research and development of projects ten years ago.

However, his mentor was one of the important experts responsible for the overall mechanical design of the rack at that time.

The old man is now too old and in poor health. He really can't make the long journey from Hunan Province to the capital for meetings, and he is unwilling to be an outsider and watch China's own heavy-duty die forging press come to fruition.

So he simply sent his most proud disciple here.

It can be regarded as the end of a worry.

Han Huiming held a can filled with tea in his hand. After everyone's attention was focused, he continued:

"The biggest difficulty in research in this area is the lack of practical experimental methods."

"Board and frame composite structures are faced with giant hydraulic equipment of more than 3 tons. Due to the amplification effect, it is impossible for us to use a scaled model to judge the stress of the actual equipment. But if we conduct a 1:1 In actual testing, it is difficult to measure the local stress of large-sized components.”

While Han Huiming lowered his head to drink water, Zhang Yong, who had been listening quietly next to him, interrupted:

"If that's the case, how do other countries overcome this problem?"

Although he had already transferred to an administrative position, he had also studied mechanical design in the past, so he still had some basic concepts in his mind.

In a place like the Commission of Science, Technology and Industry for National Defense, if someone who has no technical knowledge at all becomes the leader, many tasks will not even be carried out.

Han Huiming quickly put down the cans and bottles again and solemnly replied:

"The traditional method is to design from a theoretical level first, and then conduct actual destructive tests on key weak parts of the whole machine to demonstrate the feasibility of the theoretical calculations, and then assemble the loose parts into large components step by step. During the process, the Key large components undergo the same testing, which is why the French chose to purchase a finished device directly from the Soviet Union instead of developing it independently."

"Our country's foundation in this area is already very weak, and it requires a lot of time, material and financial resources. Zhongnan Industrial is not a school with deep pockets, and our research team has no say in the allocation of funds, so... research progress It’s been slow.”

"However, now that Mr. Chang has sufficient funds and manpower, as well as the support of comrades in the ordnance industry system, I feel that we are fully qualified to promote technology research and development in this direction. After all, rack modal analysis and dynamic design are Blocks are not only useful here, but also have great significance for other equipment manufacturing industries in the future."

Chang Haonan's impression of non-destructive stress testing methods mainly includes magnetic measurement and diffraction methods, but the accuracy is average and in some cases cannot even be quantified.

Destructive stress testing, although accurate and simple, is a miracle of sheer force.

The operation is extremely complicated, and only one site can be detected at a time. If there are multiple locations on a workpiece that need to be detected, one sample will have to be destroyed for one test.

In short, it's okay to do it once or twice, but if he wants to make the entire forging press purely by this method, then he will probably have hundreds of millions of funds...

Not quite enough.

"What if we use numerical calculations?"

Before Chang Haonan could speak, someone mentioned what he was best at.

"We have also tried, and even some time ago, we tried using the software developed by Chang Corporation, but it is always difficult to converge on the results after entering the calculation step. Many parts need to be simplified during the modeling process, and the reference value is very limited. …”

Everyone's eyes naturally turned to Chang Haonan.

"The problem does exist."

He nodded pointedly.

Although there is no computer in front of him, Chang Haonan can now review typical problems that may arise during the simulation process even in the human brain:

"The plate and frame combined die forging press has too many structural parts and the contact problem is too complicated. The traditional tetrahedral model composed of structured mesh often has strange stress concentration points at the nodes on the edge of the contact surface."

"If there is a weak slip between two objects in contact, penetration will easily occur, and if the overall component undergoes relatively large deformation, node self-locking will occur. In short, it is normal for problems to occur."

Hearing Chang Haonan's almost unthinking judgment, most people couldn't help but have expressions of regret on their faces.

After all, this seems to mean that we can only return to the traditional method just mentioned by Han Huiming.

But Han Huiming is the opposite.

Having conducted research in this area, he knew that Chang Haonan could point out the essence of the problems they faced so calmly and quickly, indicating that the latter had considered this issue before.

Definitely come prepared.

"If this is the case, the preliminary research of this project may last for a long time... Even if funding is not considered, destructive stress testing cannot be done quickly..."

An expert from the Northern Vehicle Research Institute who is relatively knowledgeable in this area sighed and said.

"A few years are indeed too slow, and the timetable I set cannot wait for such a long time."

Chang Haonan waved his hand, sat up straight, and said to the more than a hundred people participating in the project in front of him.

Not only was the weapons industry system impatient and couldn't wait too long, in fact he couldn't wait either.

According to the timetable of 601 and Sukhoi, the manufacturing process of the rear fuselage frame of the J-11A/Su-27SM will be upgraded from the current segmented manufacturing and then welding to integrated die forging.

In addition to reducing working hours and improving production efficiency, it is also a technical preparation for the manufacturing of next-generation fighter jets and future large passenger aircraft.

It doesn't matter that Damao already has two 7.5-ton hydraulic presses, but if the progress of China's heavy-duty presses is hindered, it will inevitably have an impact on the localization progress of many subsequent models.

Han Huiming, who had been looking forward to it for a long time, his eyes lit up——

He knew that Chang Haonan was too busy to micromanage all R&D work.

In this way, different people must be actually responsible for each subsystem.

The plate-frame combined structure is a research direction that he and his mentor have been adhering to over the years.

If he can really continue with this configuration, on the one hand, it will be regarded as the teacher's early regrets. On the other hand, for him, a newcomer in an unpopular major, it will almost be enough to change his destiny.

Not to mention anything else, just "responsible for the structural design of the main frame of China's first super-heavy die forging hydraulic press" is absolutely valuable.

"Stress testing of oversized workpieces is an engineering problem. Since the engineering problem cannot be solved, we can change our thinking."

"In terms of numerical simulation technology, the latest version of TORCH Multiphysics software, which will be released soon, just adds unstructured overlapping grids. This definition method allows the use of hexahedral models in the model, and the model boundaries are flexible and changeable, which is very Suitable for calculations dealing with multi-body relative motion and large deformation problems.”

"On the other hand, from a more basic mathematical theory, I happen to have done some research on the direct constraint method to deal with geometric nonlinear problems."

"In this way, although it is still impossible to completely break away from the experiment, most of the work can be done on paper, and the accuracy and quantity requirements for stress detection will be greatly reduced!"

In fact, this is indeed a coincidence.

The original reason for releasing the new version in such a hurry was to solve the problems faced by Institute 601.

But just enough to eat two fish.

But to outsiders, this seems like "Mr. Chang has everything figured out."

The next generation of Zhuge is nothing more than this.

"Then...our technical solution is initially determined to be a board and frame combination?"

Yan Yongnian was in charge of the overall design back then and had no preference as to which route to take.

As long as the die forging press can be built.

"That's right, let me assign the work tasks."

With Chang Haonan's final statement, the atmosphere in the entire small auditorium also became serious.

"Currently, since the Jiangcheng Heavy Machine Tool Factory responsible for the actual manufacturing of the forging press has not yet been officially in place, the personnel are currently divided into five research groups, which are responsible for the overall structural design; load-bearing and deformation analysis; force flow transfer simulation and monitoring; hydraulic, Preliminary research on auxiliary systems such as sensing and industrial control, as well as the research and development of supporting equipment required during the installation of the die forging press body, such as tooling trusses, etc.”

"The specific person in charge of each group is..."

"..."

For Chang Haonan, this process is already familiar.

Next, it’s time to enter the happy liver-explosion time again!