Chapter 294 Writing textbooks is really a beautiful thing

"Because today's civil engineering often has nothing to do with earth and wood, but the study of structural mechanics, which happens to be in great need of results like yours."

Liu Hongbo shrugged and replied.

"All right……"

After a brief digression, Chang Haonan quickly returned to the textbook:

"In short, no matter what, we still need to lay a good foundation, so that even if we can't apply it flexibly in the future, at least we won't make a big mistake when we go to work and apply what we have learned."

"Furthermore, if we, the graduate students from Beijing Hang University, can't even understand nonlinear finite element analysis, then others are not going to laugh at us to death?"

This last sentence was obviously very lethal. After hearing this, Liu Hongbo immediately stopped expressing his objections:

“But we have to find a way to keep students learning.”

"This is a matter of teaching material arrangement. If you ask them to do nonlinear analysis of universal states, of course they will get confused. We can lower the threshold a little and take it step by step."

Chang Haonan pushed the keyboard stand back under the table, then took a scratch pad and a pen from the side, and drew a table with a few strokes:

"In the first step, we first analyze the problem where only the material is nonlinear and other assumptions remain linear. In the second step, we extend the problem to nonlinear materials and large displacement but small strain. Finally, we consider universality. A completely nonlinear problem..."

"As for the specific arrangement of the content of this chapter, it should also include more examples. Try to let them understand some relatively simple things from these examples, such as deriving the incremental motion equation of continuous medium mechanics..."

As he spoke, he wrote down an equation with a not complicated structure on the paper:

∫p(0)^(t+Δt)u(i)δu(i)dV(0)^(t+Δt)R=∫f(t+Δt)^Sδu(i)^SdS(0)+∫ f(t+Δt)^Bδu(i)^dV(0)

"If we can guide them to this step, then whether it is only material nonlinearity, or the complete Lagrangian form and the updated Lagrangian form, they can be easily obtained through transformation, or they can be deepened in two chapters. Understanding when analyzing basic structures such as frames and thin-walled rods.”

"Uh……"

Looking at Chang Haonan who was writing furiously, Liu Hongbo felt confused for a moment:

"I know this equation, but the derivation process...why don't you write it down in more detail?"

Many years later, almost all engineering students will remember the names Chang Haonan and Liu Hongbo unforgettably.

When I was in school, my feelings towards these two textbook editors were basically gnashing of teeth.

However, after entering the workplace, they often invariably take out this textbook that often appears in their nightmares.

Some people even burn incense on that book before running the simulation program also designed by Chang Haonan, hoping that the founder will bless everything well.

However, few people know that during the writing process of this sacred book in the field of engineering simulation, the second editor also experienced a mental journey that was very similar to what they experienced during class...

Of course, writing a book cannot be explained clearly in one afternoon. Chang Haonan talked about it from afternoon to evening, and then he finally got it right.

In his previous life, when Chang Haonan was in school, he was very troubled by the randomness in the difficulty gradient design of the after-school exercises. Some of them could be calculated with almost no effort, while others were difficult to get right even if he didn't even think about it.

What's even more despicable is that the answers to many exercises are also very confusing.

So there is a poem that says:

That is to say, it is easy to see the ordinary, and it is obvious to follow the above example.

The answers to the exercises are omitted so that it is not difficult for the readers to prove themselves.

Vice versa is the same, and the inference is naturally established.

Omitting the process QED, it can be seen from the above that the proof is completed.

Therefore, although there were many complex exercises, he still considered them carefully and at least wrote down his solution ideas in the answers in detail.

He has been really kind.

In fact, the process of writing textbooks is not just an output process for Chang Haonan.

Since the sources of his theoretical knowledge are complex, including but not limited to what he learned from various papers in his previous life, what he learned at work, what he learned after his rebirth, and what he learned from the system, even from a personal perspective, he needs to do this. An opportunity to sort out your own knowledge system.

The intuitive result of this kind of combing is that after several hours of discussion with Liu Hongbo, the system's [theoretical experience] actually increased slightly by 300 again, reaching 8800 points.

This made Chang Haonan want to go to the other party to communicate with him the next day.

But this is just thinking about it.

Even though Chang Haonan only lectured for one afternoon, it would take more than ten days at the fastest to convert what he said into a textbook and then input it into the computer.

We can only take our time.

……

The following week was the most peaceful period since Chang Haonan was reborn.

In addition to the daily routine communication with Zhejiang University about the feasibility of replicating a stratospheric airship in the zero wind layer to provide information relay services, the only thing worth mentioning is that Chang Haonan finally put his long-cherished project into practice. I applied for a mobile phone number.

At this time, you can't open a card at any time like you did later. Instead, you have to register your personal information and pay a deposit, and wait about a week before you can get your phone card and mobile phone.

Ericsson GH337, 1700 yuan.

Chang Haonan chose the cheapest style.

It looks like a walkie-talkie, and the screen is pitifully small.

When this model first entered China in 1994, the price was close to yuan. However, the development of mobile phones in this era was almost as fast as the Internet. Models with a series of new functions such as color screens, flip keyboards, polyphonic ringtones, etc. were gradually released. , the price of the old model is almost the same as diving.

But it's enough.

In the end, mobile phones these days are really just "mobile phones", unlike smartphones more than 20 years later, which have almost become a personal information terminal. Therefore, as long as the network standard does not become outdated, there is no need to upgrade to a new model. necessary.

Although Ericsson GH337 is old, it is the first GSM mobile phone to enter China, so Chang Haonan can choose an 139-digit number starting with 11 instead of the 7-digit number of the analog network.

It also means that he can keep using this number if he wants.

This is undoubtedly good news for Chang Haonan who is too lazy to bother.

When he walked out of the telecommunications business hall for the second time with the phone card installed, his inner emotions were quite complicated.

On the one hand, this made him feel as if he was closer to the era before his rebirth.

On the other hand, it also means having to bear the side effects caused by mobile phones——

Jobs are coming to your door faster.

It can be said that it was not what Chang Haonan expected. Apart from the tentative dialing, the first real call to ask him about something came from Du Yishan.

It was when Chang Haonan was having lunch at home one day.

The other party said that the equipment debugging work of the high-performance computing center was nearing completion. According to the school's arrangements, when it officially opened in three days, he, the acting director, would need to run a program in person.

The logic is similar to when a construction project breaks ground and the supervisor shovels the first shovelful of soil.

Anyway, it’s just a good start.

It doesn't necessarily need to be complicated, but in short, there must be no bugs.

Anyway, you have to prepare it in advance.