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

"So where are you now?"

Chang Haonan can't remember whether the Guardian series rocket launcher is a product of the weapons industry or the aerospace industry, but in short, it has little to do with the aviation system.

Therefore, he has limited knowledge about the subsequent development of this model. He only knows that it seems to have developed a quite large model family.

Rui Xiaoting did not answer immediately, but took the mouse and opened a file on the desktop.

It is a format that Chang Haonan is very familiar with.

Engineering files of the classic finite element analysis software ABAQUS.

It is also one of the targets that Chang Haonan targeted when designing his own software.

After waiting for about two minutes, a three-dimensional structural model diagram that had been meshed was finally loaded.

"Now this is the model built when we did the finite element analysis for the Guardian 1 rocket launcher, including the launch tube group, rockets, revolving disk, car body and the entire gun."

Rui Xiaoting introduced to Chang Haonan while turning the pages:

"On this model, limited by the simulation level and computer computing power at the time, only the most basic launch dynamics and flight dynamics problems were solved."

"The final Defender 1 has achieved the goal of extending the range to 180km, and has also won the favor of some customers who are in urgent need of medium and long-range deterrence capabilities. However, overall, this model is still far from the initial expectations."

"180km should be very far, right? I remember there seems to be an international convention on the range limit of exported weapons?"

Chang Haonan is very sure that at least in the original timeline, the Guardian series was not equipped for our army's own use.

"Yes, the range of exported weapons cannot exceed 300km."

Rui Xiaoting nodded, then turned around and started rummaging in his briefcase:

"But you are right. For the vast majority of customers, the range of the Guardian 1 is actually sufficient, so this time we are focusing on improving other parts, mainly accuracy and efficiency during salvo firing. .”

“Previously, in order to avoid the impact of vibrations and tail flames generated when large rockets were launched on subsequent firings, we simply referred to the design methods of some ballistic missiles and limited the time interval between consecutive launches across the board. However, judging from the results, it was still a bit underestimated. The effect of initial disturbance on long-range ammunition is eliminated. For example, because the rocket launcher has a directional tube, there will be a locking force in the initial stage that acts on the directional button position of the projectile, which is not found in the missile system..."

"Okay, let me take a look..."

Chang Haonan took the mouse from the side and opened the simulated log file from the same folder.

It is naturally impossible to calculate such a complex multi-body dynamics problem on such a laptop. Presumably the other party also used the help of supercomputer at that time, and for a professional like him, even if he has no research on artillery engineering , but we can still see some valuable things from it.

At this time, Rui Xiaoting had just taken out a mobile hard drive, which was considered a black technology in this era, from his bag, and was going to show Chang Haonan another simulation result——

Since the current storage capacity of a single hard disk is still very small, project files and simulation results cannot even be stored together.

But when he turned around, he found that Chang Haonan had opened the running log directly and was staring at the screen intently.

"Director Chang, I have direct results. You can't tell by looking at the log..."

However, before he finished speaking, Chang Haonan pointed at a piece of content on the screen and spoke:

"In this precision design, the directional tube of the rocket launcher, and of course the rocket, should be treated as a rigid-flexible coupled multi-body system. If it is simply approximated as a pure rigid body, the simulation effect will definitely be greatly reduced."

As the range and power of weapons continue to increase, the movement produced when ammunition is fired is also getting larger and larger. As in the past, each component of the weapon system is regarded as a rigid body, and then the product is made closer to a rigid body by increasing weight or improving strength. The method has become increasingly unfeasible, so elastic supports and flexible body dynamics have been gradually developed since the 1960s and 1970s.

That is to say, it no longer pursues the absolute stability of the weapon system during the launch process (which is actually impossible to achieve), but uses high-precision vibration simulation and prediction to make the weapon stay in the vibration waveform every time it is launched. Possibly the same location, thus achieving relative consistency in the weapon system.

In other words, although the weapons and equipment designed using this idea may look wobbly when launched, the actual accuracy will be better and the weight will be much lighter.

Typical examples are the BM21 rocket launcher and PKM general machine gun.

Of course, Chang Haonan was able to understand this aspect because this idea later expanded to the field of aerospace design.

When designing the Defender 1, although the evolution of the launch frame from rigid support to elastic support was considered, the barrel coupling system was still approximated as a rigid body.

It makes sense, but not completely.

Of course, there is nothing we can do about it. The design work of Defender 1 began in the early 90s, and as Rui Xiaoting said just now, artillery equipment does not have too many resources, so it is already very awesome to be able to do this.

"Ah... ah?"

Rui Xiaoting's hand holding the hard drive was frozen in mid-air.

The conclusion itself is not surprising.

Even the graduate student who came next to me can tell you a lot about this issue.

In fact, this was exactly what he wanted to explain after taking out the mobile hard drive.

But Chang Haonan pointed out the problem directly after looking through the logs for a few minutes without even seeing any numerical calculation process!

Who is this?

What about the "not as good as us experts in the field" just mentioned?

What's worse?

Rui Xiaoting's reaction made Chang Haonan feel a little less confident:

"Uh... am I right?"

"Yes, very true."

The former silently stuffed the mobile hard drive back into his bag.

Obviously the efficiency has improved a lot compared to the expectations before coming here, but I still have a very complicated mood. What's going on?

"Now that you've figured it out, let's get straight to the point."

"In order to solve the problem you just mentioned, I have specially developed a new numerical calculation method, temporarily called the multi-body system discrete time transfer matrix method, or MS-DT-TMM for short."

"The specific idea is to linearize the dynamic equations of each component in the time domain, so that both spatial transfer and time iteration can be taken into account during analysis, and it is very suitable to be extended to rigid-flexible coupled plane motion problems. Compared to The classical transfer matrix method, which can only handle simple harmonic motion, MS... Well, my new method can analyze linear or nonlinear time-varying or time-invariant systems."

"However, the limitations of using only this method are still very large, especially the elastic dynamics analysis of complex boundaries and complex shapes still relies on other numerical analysis methods, so I am here to ask you if there is any Possibly, multiple different computational mechanics methods can be jointly applied on the same platform?”

"Of course it's possible."

Upon hearing this question, Chang Haonan laughed directly:

"Not only is it possible, I even have the tools."

"Take the information and follow me."