Chapter 489 Pulsating production line, structural upgrade issues of J-11
While Haojing Aviation Development Group and Rolls-Royce were discussing the specific introduction agreement, Chang Haonan was not idle either.
In addition to dealing with the many fragmentary problems faced after the turbofan 10 was transferred to formal research and development, he also spent a lot of free time going to the 601 Research Institute and the 112 Factory.
On the one hand, he wanted to lick the flanker lady whom he had little chance to see in his previous life.
On the other hand, it also helps them solve some application problems of TORCH Multiphysics software.
As each trial user, especially the trial users of the Super Large Cup Professional Enhanced Edition, gradually passed through the initial learning stage, some unsatisfactory aspects of the new software were gradually discovered.
This information will be fed back to the Torch Group headquarters in Beijing. However, as the person most familiar with the TORC Multiphysics software in the world, Chang Haonan will obviously be of great benefit to the subsequent software upgrades if he can go to the front line to check some actual problems in person.
In the final assembly workshop of Factory 112, dozens of workers are climbing up and down around the assembly frame to complete the final assembly of major components of the four J-11s.
“He Gong, these are...the second and third batch of four aircraft?”
According to the agreement signed with Sukhoi last year, after the completion of three batches of large component assembly of a total of six aircraft, Factory 112 can officially open the "complete machine assembly line" and enter the next step of localization.
He Ming took Chang Haonan to the side of the plane that was making the fastest progress, and reached out to touch the pitot tube at the tip of the nose.
"Yes, the original plan was to carry out the operations separately, but the final assembly of the first batch went very smoothly, so after communicating with experts from Sukhoi, we put the four aircraft in the second and third batches together for final assembly. "
Just when Chang Haonan was hesitating whether his judgment was correct, a familiar female voice behind him sounded:
As a scientific research dog, Chang Haonan quickly grasped the key points of this passage:
“The style of this assembly workshop is a bit different from what I saw in the J-8C assembly workshop next door..."
Yao Mengna straightened her clothes, got between Chang Haonan and He Ming, stood closer to the assembly frame, and began to introduce further:
"This method has two main features. In terms of space, it can operate in parallel in multiple areas, and in terms of time, it can coordinate assembly of multiple types of work. Theoretically, the production efficiency should be at least 50% higher than that of the past continuous moving production lines. 100%.”
Soon, a familiar feeling emerged.
“Senior sister?”
Even though he was not proficient in the field of production management, he could still see that there seemed to be several different types of work being performed at the same time on the front, rear, left and right sides of the aircraft.
“In other words, the actual situation...”
Chang Haonan took a few steps back as he spoke so that he could see the overall distribution of the aircraft's final assembly area.
Yao Mengna, who had been so proud just now, suddenly lost her energy. She put her hands on her hips and looked angry:
“How should I put it… Assembling an aircraft from scratch is still different from previous upgrades and overhauls, and the complexity of the work involved is far higher than I expected.”
Perhaps because of his long-term stay, the other party even cut his previously long hair to ear length.
“It's a bit like Factory 172 in Haojing?”
“How do I feel...this final assembly form is a bit like...”
Including the layout of tools and equipment and the allocation of personnel, there are some unreasonable issues, resulting in the assembly progress not looking very coherent.
It's just that the coordination between them is still a bit rough.
Looking very capable indeed, but Chang Haonan almost didn't recognize him for a while.
He turned around suddenly and found Yao Mengna wearing work clothes standing behind him.
"This final assembly model was developed by me and the team of final assembly engineers at Factory 172 when we were working on the JH7 in Haojing. It was during the time when we were working on the JH7, so you may feel that there are some familiar."
“Theoretically…”
“So after several rounds of adjustments, there will still be a problem of some teams waiting for assembly tasks when they are fully loaded, while other teams are idle waiting for assembly tasks. The overall efficiency has not changed compared with the old method of continuous mobile production..."
In fact, the set of things Yao Mengna created is very close to the later concept of “pulsating production line”.
And coincidentally, the pulsating production line in the previous life was first put into use in Haojing, and then extended to the entire aviation industry system.
It's just that the level of computer hardware and algorithms in the late 1990s was still relatively limited, so it was very difficult to optimize this advanced production method.
“You can't say that either.”
He Ming, who had been silent just now, finally spoke:
“Actually, when we first used the new method to assemble the first two aircraft, the efficiency was not as high as the original continuous moving production model.”
"Now it has been much better after several optimizations, which shows that this method still has great potential. As long as we can continue to adjust it based on actual production experience, we will definitely be able to achieve the theoretical effect." "After all, we have only built six aircraft. , production matters cannot be rushed.”
He Ming's comfort made Yao Mengna's mood obviously improve a lot.
“Actually, I also tried to use the differential evolution algorithm developed by you and Sister Xu Yang to optimize it from a mathematical perspective, but... the effect was not good.”
Chang Haonan remembered that the last time he saw Yao Mengna, the latter still called Xu Yang Researcher Xu.
The relationship between the two seems to have improved a lot during this time...
He shook his head slightly to throw away the random thoughts in his mind, and then explained:
"Although the differential evolution algorithm is advanced, it is not omnipotent. For this kind of discrete, integer, high-dimensional, large-scale, multi-constraint optimization problem, it relies heavily on the summary of problem characteristics and experience, and it is easy to fall into the trouble of local optimality. , in short, it is not suitable for application scenarios such as aircraft production lines.”
Hearing Chang Haonan's sane analysis, Yao Mengna instantly became interested:
“Teacher...Mr. Chang, do you have a better way?”
In private, Yao Mengna still used to call Junior Brother Chang Haonan, which was considered her exclusive title.
But in public, she is still relatively measured.
“Is there a better way? It may be some path planning algorithms, but it will take some extra time to study.”
“You can try using an ordinary genetic algorithm first. The effect should be better than the differential evolution algorithm.”
Chang Haonan first gave some suggestions, and then added:
“My research in the field of control science and optimization algorithms is purely out of interest. Now the turbofan 10, the die forging press and the TORC Multiphysics software all need to be handled by me personally. I am afraid that I will not have much energy to focus on them in a short period of time.”
He Ming, who had been an audience next to him, was immediately stunned by this piece of Versailles.
Good guy, you did some random research out of interest and you crushed all your peers in the country and even around the world?
Should you let others live?
But Yao Mengna has long been used to it.
She took advantage of the situation and changed the subject:
“Speaking of TORCMultiphysics, we recently encountered some difficult problems when optimizing the structure of the J-11.”
“Structural optimization?”
Chang Haonan raised his head and looked at the huge semi-finished J-11 in front of him:
“How far have you achieved it?”
Yao Mengna took him under the main wing on one side of the plane and pointed to the innermost part of the wing:
"According to the technology sharing agreement signed by both parties, Sukhoi has brought the first phase of structural optimization results to us. The difference reflected in the product is the addition of a pair of heavy loads with a maximum load capacity of 2,000kg on the innermost side of the wing. racks, increasing the total number of racks from 10 to 12.”
“We plan to introduce this upgraded new airframe starting from the fourth batch, which is the aircraft assembled with low components.”
Due to structural strength limitations, the earliest Su-27 did not have a hardpoint designed at this location, which was originally very suitable for mounting large-size air-to-surface ammunition.
In the previous generation, this problem was solved on the Su-27SM, but because the contract depth of Project 11 was far less than it is today, China did not use these two high-quality heavy-load mounting points until the introduction of the Su-30MKK in the new century.
“Now that the problem on the wing has been solved, the problem must lie in the central lifting body itself?”
Chang Haonan probably knew the optimization process of flankers, so he asked directly.
“That's right.”
Yao Mengna nodded directly:
"This is a problem that we and Sukhoi experts are struggling with. The available overload of the aircraft in a specific speed range will be reduced from +9G to +5G-+6G. Although it can be controlled by upgrading the digital fly-by-wire flight control. The impact range is minimized, but it is still a hidden danger.”
“During the structural mechanics calculation of the J-11's wing-body fusion body, we tried many methods such as dynamic overlapping grids, dynamic unstructured grids, and non-structural overlapping grids.”
“But either the generation accuracy is not up to standard, or the generation efficiency is too low, it will take several months, or the calculation time step cannot be too large, otherwise it will diverge..."
“Is there such a thing?”
The grid generation algorithm of TORCHMultiphysics was specially developed by Chang Haonan.
However, the focus of the research at that time was to solve the mesh generation problem of the dirty model, and there was indeed no specific optimization for the structural mechanics/fluid mechanics composite analysis problem of this type of wing-body fusion.
When you encounter problems now, you should naturally be very attentive:
“Let's go and see the specific situation.”
(End of this chapter)
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