This kind of discussion about the choice of technical route is naturally not easy for the vast majority of researchers who have only begun to learn about the project today.

Only a few people who Chang Haonan had planned to meet together 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 discontinued, these people were scattered to several different research institutes in the north and south of the river for various reasons.

Although research on heavy-duty hydraulic presses continues to be more or less continuous, there is little academic communication between them.

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

So, before Yan Yongnian could even figure out how to speak again, another voice sounded:

"My mentor and I have systematically studied the plate-and-frame composite structure frame 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 was only in his early 30s, and of course he could not have been involved in the development of the project ten years ago.

However, his mentor was one of the key experts responsible for the overall design of frame mechanics at that time.

The old gentleman is now too old and in poor health, so he really can't travel from Hunan Province to the capital for a meeting, and he is unwilling to watch Huaxia's own heavy-duty die forging press fall to the ground as an outsider.

So he simply sent his most proud disciple to come.

It's a matter of heart.

Han Huiming held a canned bottle full of tea in his hand, and waited until everyone's attention had passed before continuing:

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

"The plate-and-frame composite structure is facing more than 30,000 tons of giant hydraulic equipment, due to the existence of amplification effect, it is impossible for us to use the scale model to judge the force of the actual equipment, but if the actual test of 1:1 is carried out, it is difficult to measure the local stress of large-size components."

Taking advantage of Han Huiming's efforts to lower his head and drink water, Zhang Yong, who had been listening quietly next to him, interjected:

"If so, how have other countries overcome this problem?"

Although he has already changed to an administrative position, he was also a mechanical design major in the past, and he still has some basic concepts in his mind.

In a place like the Commission of Science, Technology and Industry for National Defense, if you really have a person who doesn't understand technology at all to be the leader in charge, a lot of work can't even be carried out.

Han Huiming hurriedly put down the canned bottle again and replied solemnly:

"The traditional method is to design from the theoretical level first, and then conduct practical destructive tests on the key weak parts of the whole machine, demonstrate the feasibility of theoretical calculations, and then assemble the parts into large parts step by step, and carry out the same test on the key large components in the process, which is why the French chose to buy a finished equipment directly from the Soviet Union, rather than developing it independently."

"Our country's foundation in this area is very weak, it takes a lot of time and material and financial resources, Zhongnan Industry is not a wealthy school, and our research group has little say in the allocation of funds, so ...... The progress of research has been slow. ”

"However, now that Mr. Chang has enough funds and manpower, as well as the support of the comrades of the Ordnance Industry System, I think that there are all conditions to promote the technology research and development in this direction, after all, the frame modal analysis and dynamic design are not only useful in this place, but also have great significance for other equipment manufacturing industries in the future."

Chang Haonan has the impression that the non-destructive stress testing methods mainly include magnetic measurement and diffraction, but the accuracy is average, and in some cases it is even impossible to quantify.

Destructive stress testing, while accurate and simple, is a miracle.

The operation is extremely complex, and only one site can be detected at a time, and if there are multiple parts on a piece that need to be inspected, one sample must be destroyed in one measurement.

In short, it's okay to do it once or twice, but if you want to build the entire forging press purely by this method, then the hundreds of millions of funds in his hand may be ......

Not enough.

"What if you use a numerical calculation method?"

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

"We have also tried, even some time ago, with the software developed by Chang Headquarters, but it is always difficult to converge the results after entering the calculation step, and many parts need to be simplified in the modeling process, and the reference value is very limited......"

The eyes of the crowd naturally looked at Chang Haonan.

"The problem is real."

He nodded bluntly.

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

"The number of structural parts of the plate-and-frame combined die forging press is too large, the contact problem is too complex, and the traditional tetrahedral model composed of structured meshes often has singular stress concentration points at the nodes on the edge of the contact surface."

"If there is a slight slip between the two objects in contact, it is easy to penetrate, and if the whole part is relatively large deformation, the node will be self-locking, in short, it is normal for problems to occur."

Hearing Chang Haonan's judgment almost without thinking, most people couldn't help but show a regretful expression on their faces.

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

But Han Huiming is the opposite.

Having conducted research in this area, he knew that Chang Haonan was able to point out the essence of the problem they faced so calmly and quickly, indicating that the latter had considered this aspect of the problem before.

Definitely came prepared.

"If that's the case, the preliminary research for this project will probably take quite a long time...... Even without financial consideration, destructive stress testing can't be done quickly......"

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

"A few years is really too slow, and the schedule I set can't wait that long."

Chang Haonan waved his hand, sat up straight at the same time, and said to the more than 100 people participating in the project in front of him.

Not only did the weapons industry system burn his eyebrows and couldn't wait too long, in fact, he couldn't wait.

According to the timetable of the 601 and Sukhoi, the manufacturing process of the rear fuselage bulkhead 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 man-hours and improving production efficiency, it is also a technical preparation for the next generation of fighter jets and the manufacture of large passenger aircraft in the future.

It doesn't matter if there are two 75,000-ton hydraulic presses on the Damao side, but if the progress of the heavy-duty presses on the Huaxia side is blocked, 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, had even more eyes lit up-

He knew that Chang Haonan lacked skills, and it was impossible to fully manipulate all the research and development work.

In this way, each subsystem must have different people who are actually responsible.

The plate-frame combination structure is the research direction that he and his supervisor have been insisting on over the years.

If he can really continue to go on this configuration, on the one hand, it can be regarded as the regret of the teacher's early years, and on the other hand, for him, who is in an unpopular major and a fledgling newcomer, it is almost enough to change his life against the sky

Not to mention anything else, just "responsible for the structural design of the main frame of the first super-heavy die forging hydraulic press in Huaxia" is absolutely full of gold.

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

"Technically speaking, the latest version of the soon-to-be-released TORCH Multiphysics software has just added non-structural overlapping meshes, which allows the use of hexahedral models in the model, and the model boundaries are flexible and changeable, which is very suitable for the calculation of multi-body relative motion and large deformation problems."

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

"In this way, although it is still impossible to completely detach 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!"

Actually, it's a coincidence.

Originally, I was in such a hurry to release a new version in order to solve the problems faced by the 601 Institute.

But it's just enough to eat two fish.

It's just that to outsiders, it's like "Mr. Chang has calculated everything".

In the second life, Zhuge is nothing more than that.

"That'...... Our technical solution is preliminarily determined to use the combination of plate and frame? ”

Yan Yongnian was in charge of the general design back then, and he had no preference for what route to use.

As long as you can make a die forging press.

"That's right, I'll assign the work task now."

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

"At present, because the Jiangcheng Heavy Machine Tool Factory, which is responsible for the actual manufacturing of forging presses, has not yet been officially put in place, and now the personnel are initially divided into five research groups, which are responsible for the overall structural design; load-bearing and deformation analysis; Force flow transfer simulation and monitoring; Pre-research of auxiliary systems such as hydraulics, sensing, and industrial control, as well as the research and development of supporting equipment required in the installation process of the die forging press body, such as tooling trusses. ”

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

“……”

For Chang Haonan, such a process has become familiar.

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

(End of chapter)