The military-industrial scientific research system of the academic master.

Geological exploration is by no means an easy or pleasant task, even if precise coordinates have been obtained.

Fortunately, today's technical equipment, especially vehicles and helicopters, are relatively complete, and safety is relatively guaranteed.

But if we really dig deeper into a point, it is still normal to take a few months at the shortest and a few years at the longest.

Therefore, after deploying some key points of the exploration work, Chang Haonan and Meng Zhenyuan returned to Beijing University of Aeronautics and Astronautics together.

For them, all they can do now is wait.

Fortunately, Chang Haonan has no shortage of projects.

In the next half month, in addition to the daily routine of paying attention to the progress of the Richie flow surgical method, I was guiding Li Yabo to carry out his graduation project.

In fact, it was not until the Spring Festival when Chang Haonan started his graduation project that he knew what the so-called "1-meter-class all-composite shell" specifically meant.

Gaofei wants to develop a brand new engine nacelle for the C808 passenger aircraft which is about to go into mass production.

It's the thing that holds the engine to the fuselage.

The diameter is about 1.3 meters.

If successful, the aircraft could be reduced in weight by about 300kg.

All I can say is that there is indeed a promising future in terms of technology.

But it’s not operational yet.

At present, almost all high-grade composite materials used in China are imported, and the cost is very high.

The little weight saved by replacing titanium-aluminum alloy with carbon fiber, even if extended to the entire life cycle, is not worth the extra cost spent in the manufacturing process.

Of course, there’s no harm in doing some research ahead of time.

After all, there will be many places where similar designs will be needed in the future.

In the long run, it is a major trend to replace traditional alloys with carbon-based composite materials in the outer shells of launch vehicles and ballistic missiles, the fuselages of large aircraft, and even in fan blades and casings of turbofan engines, where the working environment is not particularly harsh and the probability of damage is relatively low.

Just treat it as a technical reserve.

Of course, for an undergraduate student working on his final year project, these are still relatively far away.

Therefore, Chang Haonan's requirement for Li Yabo is to design an overall plan that is theoretically feasible.

The main purpose is to train the latter's ability to solve problems using existing tools.

Otherwise, if the students of the creator of TORCH Multiphysics cannot use the software developed by their teacher, it would be too embarrassing to say it out.

But, that's just how life is sometimes.

When you don't have expectations for something, it often gives an unexpected result.

……

One day in late March, when Chang Haonan was replying to Professor Perelman's email asking about the progress, Li Yabo suddenly popped his head in from the office:

"Teacher, please take a look. My simulation results seem a bit strange..."

Nowadays, students with laptops are rare, so Chang Haonan could only follow Li Yabo to the student office to check out the situation.

It is called a student office, but there are fewer students than teachers in the Torch Laboratory now, so in fact Li Yabo has it all to himself.

So the young man simply moved his luggage from the dormitory and started his life as a hard-working 007.

After entering the door, Chang Haonan carefully walked around a folding bed and came to Li Yabo's workstation.

On the computer screen, a finite element model is displayed, which is thick in the middle and thin at both ends, and is slightly cigar-shaped.

It was he who designed the overall plan of the engine nacelle.

Chang Haonan came closer to the screen and quickly read the results of the finite element calculation.

In 1999, that is, last year, a hardware engineer named Huang Renxun officially coined the term "GPU".

In fact, the prototype of the processor that assists the CPU in graphics processing appeared as early as the 80s.

But the GeForce256 launched by NVIDIA brought a revolutionary feature.

Real-time programmable shading technology.

TORCH Multiphysics will soon be launching a free (excluding shipping and storage carrier material costs) and optional feature update.

When the user's computer is installed with an independent GPU, the results of the finite element calculation can be directly superimposed on the surface of the 3D model in the form of graphic rendering.

Instead of just outputting a dry table like in the past.

Although in terms of results, there is no difference between the two.

But for the human eye, the former method is obviously much more intuitive.

Therefore, Chang Haonan can now tell at a glance that the design on Li Yabo's computer basically meets the project requirements proposed by Gao Fei.

“This result seems to be okay…”

He stood up again:

"Do you think there's something strange?"

At this time, Chang Haonan caught a glimpse of the annotation in the lower right corner of the screen.

Therein lies the nature of the material he has chosen.

Young's modulus 700Gpa...

The corners of his mouth twitched violently.

No need to look at other parameters.

Definitely the T700 Carbon Fiber.

It can only be said that one does not know how expensive firewood and rice are until he manages the household.

T700 has only been put into commercial use in the last two years, and because its production capacity cannot be increased, its unit price is quite high.

If you use this kind of thing in large quantities on a 50-ton regional aircraft, you might get beaten to death by the users...

Fortunately, it is still in the design stage. From the perspective of practicing, there is no big problem.

"This is it."

Li Yabo spoke as he enlarged the 3D model again and again.

Finally, Chang Haonan discovered that the carbon fiber structure on the screen was not just a shell.

Instead, it is composed of many thin layers.

“You have already studied the effect of composite material layup structure on performance?”

Chang Haonan was a little surprised.

"Yes, I think if we just provide an overall design plan, then Party A should be able to do it themselves, and there is no need to ask our research team to solve the problem."

Li Yabo’s first sentence made Chang Haonan very satisfied.

Although I kind of dislike the intention of Gaofei Group.

"After trying several different ply layup solutions, I found that the orthogonal ply is significantly better at withstanding shear loads and lateral loads, but this result is different from what I saw when I was on a business trip to Gaofei Group..."

"Also, even if they are the same orthogonal stacking, there will be differences in my two calculation results..."

"..."

In a trance, Chang Haonan seemed to see himself a few years ago in the other person.

Maximize your subjective initiative.

Of course, I am a real undergraduate after all, so there is definitely a big gap in my abilities compared to my past self.

However, this is not the most important thing.

"That's not surprising."

He listened to the other person quietly, and then replied:

"This type of carbon fiber reinforced composite material has very complex anisotropy, unstable interlaminar strength, and very different thermodynamic and mechanical properties between the fiber and the matrix. We, or rather not only us, but also the world, still do not understand the nature of this material enough."

"So, although the current TORCH Multiphysics can model the structure of multilayer composite materials using your method, it cannot perform accurate numerical simulations in this case."

"That's why I told you before that as long as we can design an overall plan that is theoretically feasible, that will be enough."

After hearing Chang Haonan's explanation, Li Yabo showed a slightly embarrassed look on his face:

"This...it turns out to be like this..."

He scratched his head and said:

"Then all this is useless..."

Originally, Li Yabo was thinking of doing the whole thing secretly and shocking the teacher for a whole year.

In the end, the job was not completed and I had to go to the teacher to help find the reason.

"That can't be said."

Chang Haonan could roughly guess what the other party was thinking, and smiled and shook his head:

"After all, you have done the entire modeling and calculation process yourself. It will be a rare experience for your future research work."

“Some experiences can only be gained through failure.”

Li Yabo nodded somewhat disappointedly.

But Chang Haonan's next words made his eyes light up:

"However, if you are really interested in the microstructure of composite materials, I can directly buy you a batch of related equipment and materials to study it experimentally."

"Really...really?"

Li Yabo could hardly believe his ears:

"I asked about this when I was on a business trip to Gaojing before. The equipment and materials are very expensive..."

Obviously, he had already secretly understood the situation.

Before Li Yabo finished speaking, Chang Haonan waved his hand:

"The equipment used for laboratory research is different from their industrial production. The cost is not that outrageous. I, your teacher, can still afford it."

"But you have to think carefully. Strictly speaking, this is already a field of materials science, not structural mechanics. Experimental research is also much more difficult and troublesome than numerical calculations..."

"I've thought it through."

Li Yabo answered firmly.

"Well."

Seeing that his student was so persistent, Chang Haonan naturally couldn't discourage him:

"Your current design will be enough for your undergraduate degree."

He pointed to the model on the computer screen:

"So, from now on, I will officially treat you as a graduate student."

Hearing this, Li Yabo couldn't help but sit up straight.

Although he didn't say anything, this action said it all.

Chang Haonan nodded slightly when he saw this, and then said solemnly:

"I'll give you one month to write me a proposal for the research on the microstructure of composite materials, and include the experimental equipment and materials you need."

"If there is no problem with the report, I will prepare it for you as soon as possible. Do you understand?"