Chapter 489 Pulsating Production Line, J-11 Structural Upgrade Issues
During the time when Haojing Aviation Group and Rolls-Royce were negotiating 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 Institute and the 112 Factory.
On the one hand, I want to lick the flanker lady who I had no chance to see in my 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 user of the Super Big 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, but Chang Haonan, as the person most familiar with the TORCH Multiphysics software in the world, if he can personally go to the front line to check some actual problems, it will obviously be helpful for subsequent software upgrades. Work goes a long way.
In the 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 batches of four aircraft?"
According to the agreement signed with Sukhoi last year, in the three batches, a total of After the completion of the six large-component assembly machines, Factory 112 can officially open the "complete machine assembly line" and enter the next step of localization.
"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. ”
He Ming took Chang Haonan to the plane with the fastest progress, and reached out to touch the pitot tube at the tip of the nose.
"The style of this assembly workshop is a bit different from what I saw in the J-8C assembly workshop next door..."
Chang Haonan took a few steps back as he spoke. You can see the overall distribution of the aircraft's final assembly area.
Although he is not proficient in the field of production management, it can be seen that there seem to be several different types of work being performed at the same time on the front, rear, left and right of the aircraft.
It's just that the coordination between them is still a bit unfamiliar.
Including the layout of tools and equipment and the allocation of personnel, there are some unreasonable things, which makes the assembly progress not very coherent.
Soon, a familiar feeling emerged.
"Why do I feel...this general assembly form is a bit like..."
Just when Chang Haonan was hesitant and didn't know whether his judgment was correct, a familiar female voice behind him sounded:
"It's a bit like Factory 172 in Haojing?"
He turned around suddenly and found Yao Mengna wearing work clothes standing behind him.
"Senior sister?"
Perhaps because of the long-term stay, the other party even cut her previous long hair to ear length.
He did look a lot more capable, but Chang Haonan almost didn’t recognize him for a while.
"This final assembly model was developed by me and the final assembly engineer team at Factory 172 when we were working on the JH-7 in Haojing. It was during the time when we were working on the JH-7, so you may feel that there are some Familiar."
Yao Mengna straightened her clothes, got between Chang Haonan and He Ming, stood closer to the assembly frame and began to introduce further:
"This This method has two main characteristics. In terms of space, it can work 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% to 100% higher than that of the past continuous moving production lines. "
"Theoretically..."
As both scientific research dogs, Chang Haonan quickly grasped the key points of this passage:
"That is to say, the actual situation..."
Yao Mengna, who had been full of pride just now, suddenly lost her energy, put her hands on her hips, and looked angry:
"How to say... 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.”
“So after several rounds of adjustments, some teams will still be at full capacity. The problem of assembly tasks waiting while other groups are idle waiting for assembly tasks, the overall efficiency has not changed much compared with the old method of continuous mobile production..."
In fact, Yao Mengna did this The set of things 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 computer hardware and algorithm levels in the late 1990s were still relatively limited, so it was very difficult to optimize this advanced production method.
“You can’t say that.”
He Ming, who had been silent just now, finally spoke:
“Actually, the first two aircraft were assembled using a new method. At that time, the efficiency was not as high as the original continuous mobile production model.”
"It's much better now after several optimizations, which shows that this method still has great potential. As long as it can be adjusted based on actual production experience, it will definitely 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.
"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, above The first time I met Yao Mengna, the latter still called Xu Yang Researcher Xu.
The relationship between the two seemed to have improved a lot during this time...
He shook his head gently, threw away the random thoughts in his mind, and then explained:
"Differential Evolution Algorithm Although advanced, it is not omnipotent. For this kind of discrete, integer, high-dimensional, large-scale, multi-constraint optimization problem, it relies heavily on summary of problem characteristics and experience, and it is easy to fall into the trouble of local optimality. In short, it is not suitable An application scenario like an aircraft production line."
Hearing Chang Haonan's succinct analysis, Yao Mengna instantly became interested:
"Master...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, probably some path planning algorithms, but it requires some extra time to study."
"You can try it first with an ordinary genetic algorithm. 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."< br>
He Ming, who had been an audience next to him, was immediately stunned by this piece of Versailles.
Good guy, you just did some random research out of interest and you crushed all your peers in the country and even the world?
Should you let others live?
But Yao Mengna has long been used to this.
She followed the trend and changed the topic:
“Speaking of TORCH Multiphysics, we also encountered some difficult problems recently when optimizing the structure of the J-11.”
“Structural optimization?”
Chang Haonan raised his head and looked at the behemoth semi-finished J-11 in front of him:
"What step have you achieved?"
Yao Mengna took him under the main wing on one side of the aircraft and pointed to the innermost part of the wing:
"According to the technology sharing agreement signed by both parties, Sukhoi has already transferred the structural optimization results of the first phase to Brought to us, the difference reflected in the product is the addition of a pair of heavy-duty pylons with a maximum load capacity of 2,000kg on the innermost side of the wing, increasing the total number of pylons from 10 to 12.”
"We plan to introduce this upgraded new airframe from the fourth batch, which is the aircraft assembled with low parts."
Due to structural strength limitations of the earliest Su-27, this was originally very suitable for carrying large loads. There is no hanging point designed for the ammunition opposite the size gap.
In the previous life, this problem was solved with the Su-27SM, but since the contract depth of Project 11 was far less than it is now, China did not use these two until the introduction of the Su-30MKK in the new century. High-quality heavy-duty hardpoint.
"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 the flankers, so he asked directly.
"Yes."
Yao Mengna nodded directly:
"This is a problem that we and Sukhoi experts are struggling with. The speed of the aircraft at a specific speed range The available overload will be reduced from +9G to the level of +5G-+6G. Although the affected range can be minimized by upgrading the digital fly-by-wire flight control, 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 unstructured overlapping grids."
"But Either the generation accuracy is not up to standard, or the generation efficiency is too low and 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 designed 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.
Now that we encounter a problem, we naturally have to be very concerned:
“Let’s go and see the specific situation.”
(End of this chapter)