At 12 o'clock sharp, YF-87 reset to zero for the second time, and the improvement route discussion meeting officially began.

Although Li Zheng has gone very deep into the field of data, just like last time, he does not know what the results he gets mean. It is like an artificial intelligence machine that does not know the language representation of its feedback.

What meaning.

In the eyes of engineers from the 17th Institute, the crack images and data obtained from these disassembly inspections pointed to a single result very clearly -

Subsynchronous precession.

In the field of aerospace, the effect of this word is equivalent to the whisper of Cthulhu...

A terrifying and unreasonable existence.

Among them, "precession" can also be called "vibration".

Speaking of vibration, this is an old friend of aerospace. It is equivalent to what BUG is to programmers and probability is to mobile game players.

During the launch process, the rocket will encounter various vibrations, and the structure and materials have their limits and cannot withstand large vibrations.

In the design stage, of course, these complex situations will be taken into consideration and various vibration reduction methods will be used. Huang Er also adopted the latest damping and variable energy pressure accumulators for vibration suppression.

Under normal circumstances, there is no problem with this design. 8.8 will succeed with a little luck.

But in the most harsh vibration environment, the engine unexpectedly emitted the low groan of Cthulhu...

This low hum was lost in the sea during the first launch and was not captured by anyone.

In the recent shaft system rupture accident, it was covered by countless huge noises, which were also unable to be captured.

But Liu Rui used his terrifying perseverance to capture clues in other test data.

On this basis, Li Zheng used mathematical and algorithmic tools to extract features and expanded the screening scope to all historical data in history overnight.

As he said, such "whispering" alone is meaningless, as dispensable as the wind blowing leaves, but when stacked together countless times...

He finally heard Cthulhu's voice.

It's just sounds in mathematical form.

Next, Zhu Mingyue went a step further and translated this murmur into engineering language——

In a harsh vibration environment, when the turbine rotor operates at supercritical speed, some wonderful changes occur in the local dynamics and material properties, causing its natural vibration frequency to change, and then to couple and resonate with the operating frequency.

This also means that there is a "rebellion" in this part, trying to rotate and vibrate in its own way.

In this process, the turbine rotor is bound to bear huge structural stress.

Those tiny, invisible cracks just happened.

When the resonance reaches a certain level and the structural stress exceeds the material yield limit, the cracks will expand rapidly and then break during violent rotation.

What’s even more frightening is that subsynchronous precession is also a self-excited vibration, which will produce greater vibrations due to vibration.

It's like 100 Liu Xiangs holding hands and forming a circle, running clockwise, and running one circle in one minute as required.

Because they are all Liu Xiang, this speed is nothing to them, so they ran very happily.

But suddenly!

A song called "Chicken You Are So Beautiful" came out.

One of them, Liu Xiang, suddenly became an idol.

Let’s start singing and dancing!

At this time, it becomes 99 Liu Xiangs and a singing and dancing idol running around in circles.

But this is not a collapse.

After all, Liu Xiang next to him will force the idol to run with him. Although it is a bit tiring, 99 Liu Xiang can still withstand one idol.

However, the scary thing is that the person being dragged away is an idol.

He would not just spread out his arms and hang his body in the air, being pulled by Liu Xiang in front and behind him to run.

He wants to sing and dance.

In fact, at the same time he transformed into an idol, he sang the next song Chicken You Are So Beautiful.

In an instant, the two Liu Xiangs on his left and right were infected and started singing and dancing.

The number of singers and dancers suddenly increased to three, which made the runners next to them miserable.

But this is just the beginning.

More cocks, you are so beautiful, have been coming in one wave after another...

When the content of singers and dancers is 1%, this circle running can still be maintained, and it will only cause imperceptible muscle tears in a few runners.

When the content reaches 3%, runners can already feel the pain of pulling their arms.

When the content reaches 5%, the pulling force will reach the endurance limit of the runner, and he will either give up or break his arm.

This is self-excited oscillation, which is both a cause and a result.

Where did the original "chicken you are too beautiful" come from and how to avoid it, it is still an engineering problem.

Just like a middle-aged man staying at home, there will always be an idol's name stuck on his face.

Since then, the logic of the accident has become completely clear.

In the conference room, Zhu Mingyue also began to reflect and summarize.

"During the first reset, we did not find local small cracks, but only noticed damage to the exhaust system."

"From a current perspective, the exhaust system problem is not isolated at all. It is a chain reaction caused by the resonance of the turbine system. However, the exhaust system at that time was relatively fragile and broke before the turbine broke."

"There is no doubt that this is the direct reason for the failure of the 8.8 launch, but it is by no means the fundamental reason."

"After the first reset after 8.8, we had a serious fluke mentality in our analysis and processing. We made the mistake of treating the headache and the foot. We only unilaterally strengthened the exhaust system, which is equivalent to giving a

A patient with pneumonia was prescribed cough medicine."

"In the end, during the 10.5 test run, the shaft system completely broke, resulting in a tragedy."

"I personally, as well as the YF-87 team from the 17th Institute, are all to blame."

"But even though I am in the position of a criminal, I still want to thank the comrades of the First Academy for their hard work in the mission of returning to zero."

"Among them, two comrades, Li Zheng and Lin Yujing, have made particularly outstanding contributions. Through in-depth data analysis, they accurately identified the pulse twice and sent the pulse condition to my eyes. However, I was eager for success and failed to do so.

On this basis, we dug deeper and just wanted to get rid of the crime as soon as possible, which led Huang Er to find himself in the predicament he is in today. I know that apologizing has no meaning, but..."

After Zhu Mingyue finished speaking, he stood up and bowed deeply to the audience.

"Dear leaders and comrades, I'm sorry."

Everyone in the conference room stood up almost at the same time, not intending to accept this apology.

"Okay." Zhao Zhenhua stepped forward in person, helped Zhu Mingyue back, and waved to the audience, "Sit down, please. Sit down."

After everyone sat down, Zhao Zhenhua sighed and said:

"I am also responsible. I pushed too hard."

"In fact, during the first zero reset, after the fault model was determined, Zhang Zhicheng believed that the accident was not simple. This exhaust system has been tested and will not fail for no reason."

"His opinion is to use another half month or so to study the cause in depth."

"it's me."

"It was me who rejected this opinion at the time and requested that the exhaust system be improved as soon as possible and the car be tested as soon as possible."

"So, don't have any psychological burden on you."

"I said from the beginning that I will set the route and follow me. If anything happens, I will be responsible."

"It's the same now. This responsibility belongs to me. This must be implemented in the report. The one who was eager for success before was not Zhu Mingyue, Zhang Zhicheng, or me, Zhao Zhenhua."

"So everyone, don't hesitate, don't feel guilty." Zhao Zhenhua waved his arms, "Keep fucking working for me. If you change it again, or if anything happens, I'll be the one to blame!"

Zhao Zhenhua's words once again aroused the emotions of the participants. No matter their age, their eyes were a little wet and red.

The top leader of a hospital can achieve this level, so why should he hesitate?

Fight!

Taking advantage of this momentum, Zhu Mingyue proposed three routes.

First, build steel plates to reinforce the entire shaft system.

Second, redesign to bypass this problem.

Third, list all possible causes of resonance and make local improvements on the carpet.

Obviously, Zhu Mingyue has mentioned the first two routes before.

Even if it is determined that the cause is subsynchronous precession, there is no clear solution internationally. It is still a cutting-edge field in engineering design, otherwise it would not be described as the whisper of Cthulhu.

It can be said that in the face of this problem, there is no 100% guaranteed solution, not even 90% solution.

Therefore, even if he didn't know the cause, Zhu Mingyue had already proposed one or two ways.

As for the third way, it is full of "gambling" on the surface.
To be continued...