Semi-Monocoque frame

[Recon 5]

It may be a little late in the thread, but I just thought of something:

The basic frame in a 'monocoque/ semi- monocoque' MS might be compared to a human skeleton. Take off everything and it won't move.

The 'movable frame' on the other hand is like the man in a suit of powered armor. Without the externals it is still completely functional- think of the 'skeletonized' Mk II walking in Evolve 2.

[Aegis]

Not really. A monocoque is actually akin to an exoskeleton like an insect, with the armour serving as the frame, while the movable frame is more akin to the human body, where all the systems are hinged onto the skeleton like all the internal organs and systems of the human body, with armour being the equivalent to skin. And as mentioned, the monocoque frame concept is slowly swept under the rug because the idea of a massive giant bipedal mech being supported by its outer shell like a lobster is way too much of stretch.

[Ryujin]

As an aside, in real life, monocoque construction is generally used for structures where weight is a primary concern. Falling in this category are a lot of civilian vehicles, especially the ones designed specifically for fuel economy in place of performance.

Military fighter aircraft, especially those that operate on carriers, generally have semi-monocoque construction, to give them the strength to handle the various shocks & stresses encountered while performing their duties.

[Jak Stoller]

To throw in some real-world stuff to just F this whole debate up...
Modern tanks are primarily mono in design, the central hull being both the armor and the primary structural unit. These tanks often way in excess of 50 tons, and I've seen before and afters of when they roll... Not a whole lot of problem holding loads.

Also, way back in the good old days of aviation, mono designs were the cats-meow. They were stronger (but heavier) than their rigid frame counterparts. Even today, semi-mono designs are fairly common in the aviation world, particularly in seaplanes.

Now to say that a mono/semi mono mecha is laughable, I'll just say this; build one for yourself, and if it crumples, good for you you were right. Now when that doesn't happen, i'll aplaud you cause you just made the first Zaku.

As for them switching back from movable frame to semi-mono, the only thing i can say is that from a design point of veiw a movable frame is a waste of weight; you've got all these nice supporting equipment that doesn't do anything but sit there and take up space.

--Jak

[Recon 5]

That space consumption isn't really wasted, though, because the movable frame is so comprehensively equipped that it could be used as a (albeit EXTREMELY fragile and definitely not very effective) mobile suit on its own. Referring back to my mention of Evolve 2: The Mk. II can even lift a beam rifle and walk with just its movable frame. I can't call that useless waste of space by any means.

[Aegis]

To throw in some real-world stuff to just F this whole debate up...
Modern tanks are primarily mono in design, the central hull being both the armor and the primary structural unit. These tanks often way in excess of 50 tons, and I've seen before and afters of when they roll... Not a whole lot of problem holding loads.

Tanks and planes also happen to be much wider and lower to the ground, and locomotion is derived from treads or wheels or a jet engine. Standing something up vertically and getting them to move with a pair of legs, on the other hand, is not gonna happen if the skin also happens to be the load bearer, especially if we expect these things to move close to or about as well as a human being the way we see mobile suits move about. Otherwise, mammals and reptiles would have exoskeletons instead of internal skeletons. Of course, being an imaginary mahine, I am more willing to accept the idea of a semi-monocoque frame for a mobile suit.

And the movable frame is essentially the mobile suit itself, albeit starving and 'naked'. Stripping off the armour will not impede the machine's function whatsoever, just that things like dust and dirt can do wonders to the circuits of the machine, just like us walking around without skin invites all the germs to do wonders to the body.

[minovskycore_0180er]

Can someone tell me if a movable frame is only movable because the waist twists, pivots or both

[Draco Starcloud]

Can someone tell me if a movable frame is only movable because the waist twists, pivots or both

No, it isn't called a Movable Frame because the waist moves.

[HalfDemonInuyasha]

The movable frame probably is based on the concept itself. Less armor which allows much greater speed and mobility. And without the bulky armor covering the body like a shell, but having a skeletal frame with everything placed on it, it also allows greater degrees of movement with the limbs, much closer to those that a human is capable of.

[ryu289]

Apologies my friends for restarting this thread, but there was a point here that I found very relevant to my research on mecha plausability.

Plus, just thinking about it shows how ridiculous the idea is. A mobile suit made in monocoque fashion would simply crumble under the laws of physics, UC or no.

Uh, sorry, when did human skin start being made out of Luna Titanium? Or even High Tensile Steel?

Considering the structural implausibility of 18m tall giant robots of any design, it's not really fair to go "lolz, no skeleton=fail". When you're packing as thick of armour as OYW mobile suits were (especially when they were listed at say, 105 tonnes rather than 65 for the Gundam back in the early '80s), god knows making it structural is going to help you out a bunch. Even if it's not the primary load bearer, that damned near impenetrable Luna Titanium shell on the RX-78 would allow you to cut down the internal skeleton a ton. And guess what, that'd be a semi-monocoque.

A Zaku, well, that one could be harder to touch, but a monocoque doesn't necessarily mean the primary structure is the outer covering, even though that's the way it's been described in MS terms for the most part. If you look at say, a convertible with unibody (monocoque) construction, it'll probably only be the rear fenders of the frame that are visible as bodywork, plus the firewall and the rear bulkhead in the interiour. Depending on the kind of racecar, the only part of the tub out there might be the roof. It's not entirely out of suggestion for a Zaku's torso to be an exposed structural unit, while the rest is I dunno, some sort of hollow skeleton, where say, some of the actuators and such are inside as well as outside, while the armour is bolted on.


And just to jump back to downsized MS, even by cutting down the size of them by 3-5m+, the structural loads are actually reduced a lot. Possibly to the extent that thin armour was once again capable of providing some additional support. The F91's torso itself seems to be something of a semi-monocoque, with 2 large side bulkheads running from front all the way to the back of the thruster array. Same with the Strike and friends, for what it's worth.

I find the last paragraph to be very interesting as it seems the writer was on the money. As per the wiki:
https://gundam.fandom.com/wiki/F91_Gundam_F91

Multiple Construction Armor (MCA) is a multifunctional structural material in which the functions of electronic equipment, such as circulatory and cooling systems, are incorporated into the MS’ armor layers, making more efficient use of the highly compact MS’ limited internal space. The technology for embedding electrical functions into a structural material is first established in U.C.0090s with the development of the Psycho-Frame.[4][9] MCA is an application of this technology after further development; it uses special structural materials alongside heterogeneous crystallization coupling technology that uses I-Fields.[1][9]

Interestingly this sounds like an updated version of the semi-monocoque concept. The armour is providing additional support for the mech by being an attached outer shell with internal support structure...in this case the internal supports contain functions of the electronics, reducing the necessary size by a bit.

Off course I feel this would only be scratching the surface of the potential for this technology.

Here is a good way of looking at it: https://www.explainthatstuff.com/self-h ... rials.html

First a little context

Embedded healing agents are simple and effective, but they do have a drawback: interrupting the structure of the material with capsules can actually weaken it, potentially increasing the risk of failure—which is the very problem we're trying to solve! Now the human body doesn't fix damage this way with makeshift repair materials waiting inside every bit of skin and bone in case we happen to cut ourselves or fall over. Instead, our body has an amazingly comprehensive vascular system (a network of blood vessels of different sizes) that transport blood and oxygen for energy and repair. If damage occurs, our blood system simply pumps extra resources to the places where they're needed, but only when they're needed.

Materials scientists have been trying to design self-healing materials that work the same way. Some have networks of extremely thin vascular tubes (around 100 microns thick—a little thicker than an average human hair) built into them that can pump healing agents (adhesives, or whatever else is needed) to the point of failure only when they need to do so. The tubes lead into pressurized reservoirs (think of syringes that are already pushed in slightly). When a failure occurs, the pressure is released at one end of the tube causing the healing agent to pump in to the place where it's needed. Although this method can seal cracks up to ten times the size that the microcapsule method can manage, it works more slowly because the repair material has further to travel; that could pose a problem if a crack is spreading faster than it's being repaired. But in something like a skyscraper or a bridge, where a failure might appear and creep (spread slowly) over months or years, a system of built-in repair tubes could certainly work well.

Now how it would relate to mobile suits:

Most of us know shape memory materials through relatively trivial everyday applications such as eyeglasses, made from alloys like nitinol (nickel-titanium), that flex exactly back to shape when you bend and then release them. Usually, shape memory works in a more complex (and interesting) way than this (read all about it in our detailed article on shape memory); typically you need to heat (or otherwise supply energy to) a material to make it snap back to its original, preferred form. Self-healing shape-memory materials therefore need some sort of mechanism for delivering heat to the place where damage has occurred.

In practice, that might be an embedded network of fiber-optic cables similar to the vascular networks used in other self-healing materials except that, instead of pumping up a polymer or adhesive, these tubes are used to feed laser light and heat energy to the point of failure. That causes them to flip back into ("remember") their preferred shape, effectively reversing the damage. How do the tubes know where to deliver their light? If the material cracks, it also cracks the fiber-optic tubes embedded inside it so the laser light they carry leaks out directly at the point of failure. Although you might think fiber-optic tubes would weaken a material, they can actually strengthen it by turning it into a fiber-reinforced composite (effectively, they serve as the fibers you'd get in something like fiberglass, or like the steel "rebar" rods in reinforced concrete). Systems like this are sometimes known as autonomous adaptive structures and have been pioneered by materials engineer Henry Sodano.

Confused? Well please keep in mind how thing these "veins" are described aas we look at how one very important piece of Mobile suit tech is described: https://gundam.fandom.com/wiki/Gundam_Wiki:Technology

The joints of Zeon mobile suits are driven by a fluid pulse system, which used a pulse converter to turn the energy produced by the atomic reactor into pulses of pressure within a fluid. Thousands of fluid pipes, finer than human hairs, transmitted these pulses at supersonic speed to the rotary cylinders which drove the joints. This system yielded a higher operating speed than hydraulics, and lower weight and greater structural simplicity than electric motors. The exposed power cables seen on some Zeon mobile suits, such as the Zaku II series, are part of the fluid pulse system, connecting the reactor to each joint.

See what is bolded? Remember what I asked to keep in mind before? Granted while I think by the time of F91 mobile suits would be using something more advanced that nuclear-powered pulsed-power hydraulics, I do think a similiar system using energy pulses delivered from the reactor via fiber optics could be very viable.

In addition: https://www.laserfocusworld.com/fiber-o ... obot-hands

"If you want robots to work autonomously and to react safely to unexpected forces in everyday environments, you need robotic hands that have more sensors than is typical today," said Yong-Lae Park, assistant professor of robotics. "Human skin contains thousands of tactile sensory units only in the fingertip and a spider has hundreds of mechanoreceptors on each leg, but even a state-of-the-art humanoid such as NASA's Robonaut has only 42 sensors in its hand and wrist."

Adding conventional pressure or force sensors is problematic because wiring can be complicated, prone to breaking, and susceptible to interference from electric motors and other electromagnetic devices. But a single optical fiber can contain several sensors; all of the sensors in each of the fingers of the CMU hand are connected with four fibers, although, theoretically, a single fiber could do the job, Park said.

Is what I am saying understandable?

[Chris]

For god's sakes, I don't care what you think is relevant, DO NOT RESURRECT A 13-YEAR-OLD THREAD.