Lanzhou Automobile released two body technologies, is the real level worthy of "the world's first"?

Although people usually don't care much about the white body, it is often the first thing to be questioned in the event of a collision.

As a new force of its own brand, Lan Tu Automobile has a strong momentum this year. Dongfeng Company has positioned Lan Tu as a high-end national automobile brand with sustainable development. How can you take out some dry goods with such a high tonality?

Recently, Lan Tu released two world-first car body technologies at the 2020 China Car Body Conference, which are technical upgrades for safety. Because the car body technology is mainly based on the traditional material and structure technology, its updating speed is much slower than the intelligent network technology. Under the premise that Dongfeng Motor has not accumulated strong technology before, it is really risky to hang the word "the world's number one".

It is necessary for us to pay attention to the technical strength of Lan Tu car body.

This technology is a technical demonstration for a specific model. On the iFree production version of BIW, Lan Tu Automotive applied two new technologies:

1. Body structure, the first TRB+ patch composite structure thermoforming A-pillar, and TRB aluminum-silicon coating thermoforming material for B-pillar;

Second, in terms of body strength, the 2000MPa aluminum-silicon coated automobile door collision beam is used for the first time in the global models.

IFree production version is aimed at medium and large intelligent electric SUVs.

The first scheme is about the direction of body structure, so it is right to focus on A-pillar and B-pillar, because A-pillar and B-pillar play an important role in resisting frontal collision, side collision and rollover accidents.

Because of different collisions, the importance of A-pillar and B-pillar is also different, and the rollover accident can best reflect their comprehensive ability. Therefore, in terms of roof static pressure (rollover accident evaluation) under the joint action of A-pillar and B-pillar, Lan Tu released specific test data, saying that this first structural scheme can make the peak pressure of the car body reach 100kN or above.

What is this concept? As far as China is concerned, the peak static pressure on the roof of medium and large SUVs is 60kN~80kN, which is relatively common, and then excellent.

Although rollover accidents only account for about 3% of the total traffic accidents, the passenger mortality caused by rollover accidents is the highest among all traffic accidents, accounting for more than 10%.

For example, Tiguan L, Volvo XC60 and Mercedes-Benz GLC are similar in size to the iFree production version? L, the peak load is divided into 67.876KN, 9 1.677KN and122.438+06kn .. The production version of IFree exceeds 100KN, and the performance is really good.

The data comes from China Insurance Research Institute.

With regard to the strength of the car body, Lan Tu Automobile emphasized that it is the first time in the world that the door anti-collision beam made of 2000MPa Al-Si coating material has high strength and corrosion resistance.

It's interesting to take out the door bumper separately. The evaluation of door anti-collision beam is usually not paid much attention to, but as a key reinforcement to resist side collision, it can play a role in reducing collision intrusion. And why do you want to ask the question of anti-corrosion? The door is easy to get water. In fact, the interior of the car door is also designed with a drain tank to facilitate the incoming water to flow out as soon as possible.

From the published information, it is necessary for us to interpret it from two aspects.

First, whether their actual effects have been exaggerated;

Second, how do these technologies compare with the performance in the industry?

Accurately speaking, the roof static pressure test does not completely look at the peak pressure, but calculates the ratio of the maximum bearing capacity of the roof to the vehicle kerb mass force. This is not difficult to understand, because the pressure on the roof when the car rolls comes from the self-weight, and the fat man's head landing is definitely more harmful than the thin man's head landing.

According to IIHS rules, when the ratio of load to vehicle weight reaches 3.25 or above, it is considered as "acceptable", and it is considered as "good" when it exceeds 4. Tiguan L, Volvo XC60, Mercedes-Benz GLC? The load-to-mass ratios of L are 4.44, 5.06 and 6.75, respectively, which all perform well.

However, since Lan Tu has not been mass-produced, the dead weight data has not been released. Consider? IFree production version of Lan Tu is positioned in the medium and large intelligent electric SUV. Without all-aluminum body setting, the body weight is larger, which is expected to be equivalent to Volvo XC60.

As for the technical means itself, the application of TRB+ patch composite structure is not bad. TRB refers to variable cross-section rolling technology, which has the advantage of effectively improving bending resistance. It is an excellent technical means for A-pillar with large curvature and easy to be damaged by collision. TRB variable cross-section rolling technology also contributes to lightweight improvement. Its method is to thin the plate in a specific area before stamping. After stamping, unnecessary material waste can be avoided, and the weight of the non-bearing part can be reduced.

However, TRB technology is not used by Lan Tu, such as SAIC-GM's Wuhan factory in Wuhan. So it depends on how advanced the element patch is. In fact, "Patch" refers to patch in English, which means reinforcing plate when it corresponds to cars.

As far as technical ideas are concerned, there is nothing particularly novel. Compared with the carbon fiber reinforced composite reinforcement plate used in BMW 7 Series, it is still relatively weak. However, considering that the safety measures within the cost have been used, it is still worthy of recognition.

Generally, 1000~ 1500Mpa high-strength steel is used for car door collision beams, and Lan Tu uses 2000MPa aluminum-silicon coating material for car door collision beams, which is not bad.

But for SUVs, especially the production version of Lan Tu iFree, which locates pure electric SUVs, the more critical component is actually the door rail. Because of the high posture of the car body, the door rail will participate in the collision more in the side collision. Moreover, considering that the battery pack will be designed on the chassis now, the strength and structural design of the door rail beam become more critical. This is why brands such as Tesla and Weilai have novel designs on the railings.

Models? 3. The reinforced beam with hollow structure is designed for the inner plate of the door rail, which can strengthen the ability of resisting collision.

Weilai ES8 adopts integrated cavity bottom beam design.

Comparing these two models, the threshold beam of Lan Tu iFree production version is made of thermoformed steel with a thickness of over 1500MPa, but the structure is not specified. It should follow the traditional body design, which is not particularly novel.

In addition to the above, Lan Tu iFree production version of high-strength steel in white body accounts for 75%, of which the thermoforming ratio above 1500MPa is as high as 3 1%, which is mainly used for body A? Column, b? Column, threshold, middle passage, seat beam, front and rear longitudinal beams, front and rear door anti-collision beams.

Judging from this set of data, its overall performance is quite good. In contrast, the proportion of hot-formed steel is ahead of many luxury brands such as Audi e-tron(27%) and BMW X7( 16%).

In addition, the overall coordination and toughness of the body-in-white should also be taken into account. Torsional stiffness is an important index, and the static torsional stiffness of Lan Tu iFree white body is as high as 39.3 kN m/deg. This level is not much different from Weilai ES8 (44.14n m/deg/deg), but much better than the mainstream 20kn m/deg ~ 30kn m/deg.

High torsional stiffness, better ride comfort and better NVH performance.

However, it should be noted that the torsional stiffness here should be included in the battery pack, because the battery pack will strengthen the torsional stiffness of the white body, so the data may be exaggerated.

For comparison, I estimated that the torsional stiffness of the white body of Weilai ES8 is 32.6? N m/deg or so, but even so, even if the torsional stiffness of the white body of the production version of Lan Tu iFree is reduced to 29.3 kn m/deg, the performance is still very good.

From the time line, Lan Tu Auto officially released its brand strategy and the first concept car iLand in July 2020, and released the world's first mass-produced concept car iFree in September. The medium and large intelligent electric SUV based on iFree has completed the high temperature plateau test. Before the mass production of 202 1, the strict tests of global "three highs", "special events" and "all-round enhancement" will be completed.

In just one or two years, Lan Tu's task is urgent. From today's analysis, we can't say how amazing the production version of Lan Tu iFree is, but the good technology that can be used is indeed used within the controllable cost range. In order to support the rise of national brands, I think within a reasonable range, everyone will not pay special attention to publicity. 202 1 year is coming. Good luck to Lan Tu.

Figure? |? From the network

This article comes from car home, the author of the car manufacturer, and does not represent car home's position.