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New thread where I talk with myself about certain topics to cope with my shitty life.

HYBRIDIZATION EFFECT OF GLASS AND CARBON FIBER ON MECHANICAL PROPERTIES OF EPOXY BASED COMPOSITES

https://pecongress.org.pk/images/upload/books/16-Hybirdization%20Effect%20of%20Glass%20and%20Corbon%20Fiber%20on%20Mechanical.pdf
>>
>>1611180
Mixing glass and carbon fiber can give a middle ground between the strength of glass and the stiffness of carbon.
>>
>>1611180
Expensive but interesting method to improve composites:

https://www.plasticportal.eu/en/radiation-crosslinking-%E2%80%93-way-to-improve-the-properties-of-polymers-part-3/c/2768/

More about improving composites with a small fraction of rubber:

https://www.researchgate.net/publication/311981216_Mechanical_Properties_of_EpoxyRubber_Blends
>>
>>1611180
https://scitechdaily.com/scientists-invent-new-glue-thats-activated-by-magnetic-field-saves-on-energy-time-and-space/
>>
>>1611180
I don't know how expensive graphene and graphene oxide is, but it is another possible reinforcement/filler:

https://pubs.acs.org/doi/10.1021/acsami.8b13018

https://www.sciencedirect.com/science/article/abs/pii/S0266353816303967
>>
>>1611180
Carbon fiber and foam cores:

https://youtu.be/0MuXV3ywH_U?t=625
>>
>>1611180
Another clean and high energy density fuel that is going to be memoryholed:

http://algaealgae.com/
>>
>>1611360
https://www.intechopen.com/books/anaerobic-digestion/techno-economic-analysis-of-biogas-production-from-microalgae-through-anaerobic-digestion

The anaerobic digester was designed to treat the un-dewatered whole algae culture from the pond. The energy-intensive steps like algae harvesting and dewatering are avoided in this process which is different from most research. The product biogas was analyzed for economic performance in two different applications: biogas purification or electricity production through combined heat and power.

There seems to be all sorts of possible improvements involving temperature, electromagnetism, gasses, solar irradiation, the chemical properties of the pound...
>>
>>1611409
*pond

Maybe some way to verticalize it:

https://www.youtube.com/watch?v=bsQCj_PaWN0
>>
>>1611360
>>1611409
>>1611412
https://pubs.acs.org/doi/10.1021/acs.iecr.9b00270

In this work, a mathematical model describing microalgae in varying light and temperature conditions is used to propose an optimized operation policy to increase productivity. The model is calibrated experimentally to describe the growth of Scenedesmus sp. cultivated in two outdoor pilot photobioreactors with different volumes and then used to maximize algal biomass productivity by proposing a new harvesting policy of the culture. Experimental tests showed that a significant productivity increase is achievable using the optimized procedure. ** Simulated tests also highlighted that the additional implementation of an optimal temperature control strategy may lead to double biomass production. **
>>
>>1611455
Another simple fuel derived from algae biomass, biochar:

Yu, K.L., Show, P.L., Ong, H.C. et al. Biochar production from microalgae cultivation through pyrolysis as a sustainable carbon sequestration and biorefinery approach. Clean Techn Environ Policy 20, 2047–2055 (2018).

Biochar is also a fertilizer used in the Amazon forest, which has a very poor soil:

http://biocharnow.com/history/
>>
>>1611188
http://jntuhceh.org/web/tutorials/faculty/866_ic22-2014.pdf

The experimental investigation on tensile and flexural behaviour of fly ash reinforced glass fiber epoxy composites with different weight percent of fly ash have been carried out. The conclusions drawn from the present work are.

1. The tensile strength of the composites varied from 14.7727MPa to 27.1790MPa and the maximum is obtained for composite with 6 grams fly ash.

2. The maximum tensile modulus of elasticity is obtained for the composite with 8 grams fly ash.

3. The flexural strength of the composite varies from 81.648 MPa to 110.497 MPa. The maximum flexural strength is obtained for the composite with 4 grams fly ash.
>>
>>1611180
Another way to use biomass, it doesn't necessarily need to become hydrogen as the final product:

https://www.energy.gov/eere/fuelcells/hydrogen-production-biomass-derived-liquid-reforming
>>
>>1611668
https://www.intechopen.com/books/progress-in-biomass-and-bioenergy-production/preparation-and-characterization-of-bio-oil-from-biomass

It seems adequate for heating, turbines and heat engines.
>>
>>1611180
Another method to apply resin:

https://www.airtech.com/resin-infusion
>>
>>1611180
Increasing the adhesion between the epoxy and the fibers is also way to improve the composite:

http://www.kdm.p.lodz.pl/articles/2018/4/[23540192%20-%20Mechanics%20and%20Mechanical%20Engineering]%20Improvement%20of%20the%20Interfacial%20Adhesion%20Between%20Fiber%20and%20Matrix.pdf

https://www.researchgate.net/publication/233348510_Improvement_of_Interfacial_Adhesion_of_Glass_FiberEpoxy_Composite_by_Using_Plasma_Polymerized_Glass_Fibers
>>
>>1611967
Or changing the resin:

https://www.researchgate.net/publication/327645825_Environmentally-friendly_alternatives_for_epoxy_resin_composites_based_on_waste_valorisation

Thermoset formulations using bio-based resins from waste vegetable oil (WVO) were investigated. Valorisation of this feedstock brings environmental, social and economic benefits to the production chain. Blends of DGEBA and epoxidized WVO (0 to 50 wt%) were produced and optimised formulations were used to manufacture composites laminates. This approach produced of engineering materials combining two waste streams. Results herein presented open space to produce more sustainable epoxy resins for composite industry with attractive properties.

--

Despite compromises previously observed in mechanical properties of thermosets, composites produced with 30EPVO/rCF presented higher tensile strength (157 ± 24 MPa, 49.5% increase) and superior Young`s modulus (18 ± 8 GPa, 63% increase) in comparison with the reference formulation.
Nevertheless, these results also demonstrated that the viscosity reduction achieved by the addition of bio-based epoxy in the formulation could enhance fibre impregnation, therefore improving the overall processability and leading to panels with satisfactory mechanical properties. Favourable fibre/matrix interaction was detected in both sets of formulations. Additionally, panels produced with the bio-based blend can be explored for weight-reduction applications since 30EPVO/rCF composite presented a density of 1.16 g cm-3, 4 % smaller than the benchmark produced with DGEBA (1.21 g cm-3). All these features were achieved whilst improving the bio-based character of the composite from 9.6 wt% in the benchmark material to 26.6 wt% when the bio-based epoxy was added to the formulation.
>>
>>1611293
Comparing fiber glass and foam with aluminum:

https://www.youtube.com/watch?v=7eUt0YnNF3o
>>
>>1611188
>>1611203
https://davidneat.wordpress.com/materials/casting/fillers-for-resin/common-fillers-for-resin-casting/
>>
>>1611471
Low-Cost Carbon Fillers to Improve Mechanical Properties and Conductivity of Epoxy Composites

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6418987/
>>
>>1611293
>>1611985
This can carve the monocoque of a car easily, the problem is finding the right subdivisions, structure, materials, ... to make it safe enough:

https://www.youtube.com/watch?v=R6REEMFYVao

Using certain electric drivetrains would require way less development than using a regular ICE one. And they don't necessarily need to use only batteries.
>>
>>1611180
Juiced:

https://www.youtube.com/watch?v=_y45i0Yi8oo

(yes, most of this crap comes from a handler, I only repost it here because it's interesting)
>>
>>1612196
Foam Types for Fiberglass Work

https://www.youtube.com/watch?v=d1ouWFt_yRA
>>
>>1612196
And it was also used in racing motorcycles:

https://www.slideshare.net/abhisheksantosh12/monocoque-chassis-for-motorcycles

(please ignore the freemason bullshit)

Maintenance is also another concern which may have a solution depending on how the monocoque is partitioned and "glued". Woodworking has a lot of techniques used to join parts together with minimal use of glue and nails that could serve as inspiration.

Some advertising about CAD for composite monocoques (I don't know if they fully support elaborate composites with cores):

https://vinsmotors.com/en/news/smartcae/
>>
>>1611180
Many manufacturing processes can be partially automated with small assistants that reduce the need for excessive focus and finer movements, and this isn't expensive, for example:

https://www.sewingmachinesplus.com/brother-cs6000i.php

Welding, metal forming, cutting or painting certain shapes and many others are candidates for such technologies.
>>
>>1612714
More complex automations also seem accessible nowadays:

Computer Aided Design of a Low-Cost Painting Robot

https://hal.archives-ouvertes.fr/hal-01700365/document
>>
>>1612717
Large DIY CNC routers are affordable and enough for small and medium scale production using light materials:

https://hackaday.com/2020/11/28/scratch-building-a-supersized-cnc-router/

https://makezine.com/2017/03/29/building-cnc-router-kit/

https://www.instructables.com/DIY-CNC-Router-Build-large-Format-5x10ft-Rack-and-/
>>
>>1612883
There are also many affordable or DIY 3D printers which can be used for smaller details, the printed objects can be reinforced with fiber fabrics (glass, carbon, basalt, metal fiber, natural fibers, ...), use strong filaments, a lot of tweaking for the model and printing settings is necessary...

https://3dprinting.com/how-to/how-to-get-stronger-fdm-3d-prints/

https://3dprinterly.com/are-3d-printed-parts-strong/

https://www.3dsourced.com/3d-printer-materials/wood-3d-printing-printer-filament/

(wood requires post-treatment for fireproofing and durability)
>>
>>1612935
https://www.thevirtualfoundry.com/help
>>
>>1612714
One affordable way to have more consistency in both fiber cloths or other fabrics being used is to break the surface into templates inside the CAD software, making markings in the foam using the CNC router, or have a map of which template goes where in case of pure fabrics, and following a process of matching the right markings with respective their templates:

https://quiltsocial.com/8-essential-tips-for-rotary-cutting-curved-templates/

The templates can be printed, machined, ... this is obvious advice but usually fiber is used almost randomly. And planning the use of templates can also reduce wasted material.
>>
>>1611180
Video about the fluidic propulsion system:

https://www.youtube.com/watch?v=bPZI6XoHi10
>>
>>1613073
Other promising VTOLs:

https://www.pterodynamics.com/transwing

https://www.youtube.com/watch?v=yNF7d2SbHoM
>>
>>1612405
Many foams exist, including metal foams and hybrid foams such as:

https://www.saertex.com/en/products/saerfoam
>>
>>1613096
https://www.techexplorist.com/new-metal-foam-bulletproof-heavy-steel-armor/23850/
>>
>>1611180
https://www.techexplorist.com/generating-electricity-shadows/32437/

...

During experiments, scientists found that this SEG is twice as efficient as existing silicon solar cells.

...

It is composed of a set of SEG cells that are arranged in a flexible and transparent plastic film. Each section is a thin film of gold deposited on a silicon wafer. Carefully designed, the SEG can be created at a lower cost compared to commercial solar cells.

...

In future research, scientists will experiment with other materials, besides gold, to reduce the cost of the SEG.

----

Another improvement to solar panels borrowed from concentrating solar power:

https://www.youtube.com/watch?v=DsEgpegzOAw

Tracking and aligning with the sun's position is another idea that could be borrowed from CSP.
>>
>>1613102
Some CSPs don't seem to use proper absorption materials:

https://www.sciencedirect.com/science/article/pii/B9781845697693500157

Some CSPs decouple heat harvesting from the conversion of heat to electricity:

https://www.youtube.com/watch?v=UQ6GKAOK-LE
>>
>>1613073
>>1613095
INVESTIGATION OF ‘JUMP TAKE-OFF’ POSSIBILITY FOR THE NEW CONCEPT OF MODERN AUTOGYRO

http://www.icas.org/ICAS_ARCHIVE/ICAS2018/data/papers/ICAS2018_0630_paper.pdf
>>
>>1613110
Other gyrocopters besides the (jewed) CarterCopter/PAV and Avian 2/180 were capable of jump take-offs:

https://www.youtube.com/watch?v=y_COkkFuchA

https://www.youtube.com/watch?v=hI5cAgWmShU

https://www.youtube.com/watch?v=nWjBTROfLMQ

https://www.youtube.com/watch?v=nsDQ9avFtng
>>
>>1613103
Most energy harveting solutions don't scale well, and concentrating solar is one example:

https://www.youtube.com/watch?v=iJCfsqvEx1w

But it could be used locally after many tweaks, I think the heat from this collector is enough for some smaller generators.
>>
>>1613073
>>1613095
>>1613110
>>1613139
STOL is still a viable alternative to VTOL, there are some existing airplanes capable of it and many unexplored possibilities:

https://www.youtube.com/watch?v=bi3WljC-Rsc

Video about advanced canard control:

https://www.youtube.com/watch?v=AOj5FxNj7lE
>>
>>1613096
>>1613099
https://www.researchgate.net/publication/312476985_Ultra-lightweight_cellulose_foam_material_preparation_and_properties
>>
>>1613505
More cellulose foams:

https://www.brikbase.org/sites/default/files/best3_kang.pdf

https://www.mdpi.com/2073-4360/10/12/1319/htm
>>
>>1613507
Pine oil foams:

https://pubs.acs.org/doi/10.1021/acssuschemeng.7b01253#
>>
>>1613505
Non-flammable polyimide materials for aircraft and spacecraft applications

https://www.sciencedirect.com/science/article/abs/pii/009457658090051X

Recent Trends of Foaming in Polymer Processing: A Review

https://www.mdpi.com/2073-4360/11/6/953
>>
>>1613505
Natural Cork Agglomerate Employed as an Environmentally Friendly Solution for Quiet Sandwich Composites

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3348538/
>>
>>1611180
Another review about composite materials:

https://www.intechopen.com/books/textiles-for-advanced-applications/textile-reinforced-structural-composites-for-advanced-applications
>>
>>1611180
https://asmedigitalcollection.asme.org/SMASIS/proceedings-abstract/SMASIS2010/44168/115/341574

The primary purposes of a core in a sandwich composite are to keep the face sheets separated by a fixed distance and to transmit shear stresses. Syntactic foam cores consisting of hollow glass microspheres and resin can form strong, lightweight cores. By underfilling the interstitial space in a packed microsphere bed with a binder, a three-phase syntactic foam is created that has a percolated void network. In a sealed sandwich composite, a void network allows for the entire core of the sandwich composite to be evacuated and mechanically compressed by the exterior pressure. By combining this compression with a heating cycle, it is possible to repair core cracking and core/face sheet interface debonding when a reversible binder is used. Upon cooling, the healed sandwich restores its properties. We examine the relation between the mechanical properties of these sandwich composites and the healing methodologies.
>>
>>1611180
Natural fibers are a proper replacement for glass or carbon depending on the application, but it seems they are also great reinforcements:

Bamboo and glass fibers reinforced composite

https://www.slideshare.net/HrishikeshGhewade/bamboo-and-glass-fibers-reinforced-composite

Experimental Analysis of Bamboo and E-Glass Fiber Reinforced Epoxy Hybrid Composite

https://www.davidpublisher.org/Public/uploads/Contribute/582578c944aa2.pdf

(there are many articles about the use of other natural fibers mixed with fiberglass, such as jute and banana fiber, all of them with promising results)
>>
>>1611180
The external surface look and feel can be improved by painting techniques based on metal powders:

https://www.innometal.com/

Maybe this can be applied to an outer layer of the composite using appropriate resins:

https://www.smooth-on.com/tutorials/metal-cold-casting-smooth-cast-325-resin/
>>
>>1612883
Maybe those CNCs can also be used to shape metal, it depends on how they are built:

https://hackaday.com/2018/03/14/incremental-sheet-forming-with-a-cnc-machine/
>>
>>1613769
Metal coatings have other uses in manufacturings:

https://www.innometal.de/innomould/verfahren/

Another brand of metal paint:

https://www.verometal.com/metals-finishes/
>>
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>>1611180
Pre-made composite panels can't be bent, but they can be folded and crushed. In those cases, complex shapes can be made via rigid origami:

https://medium.com/quarkmagazine/unfolding-origami-engineering-5bbee7fa0e13
>>
>>1613803
Example:

https://www.youtube.com/watch?v=JoJ2rWTUA3w

https://www.youtube.com/watch?v=qCj-bQDLmfc
>>
>>1611180
Previous threads:

https://archive.nyafuu.org/n/thread/1566172

https://archive.nyafuu.org/n/thread/1536572
>>
>>1613096
Carbon Foams; Precursors, Properties and Applications

https://www.jst.go.jp/sicp/ws2010_tu/abstract/2-Ferhat.pdf
>>
>>1612196
>>1612883
It can also be used to build molds if many similar parts need to be made:

https://www.youtube.com/watch?v=imQ6DEa9jVc

>>1611293
>>1611985
Another composite:

https://www.youtube.com/watch?v=6Vkhdx_v_iY
>>
>>1612935
>>1613989
The same applies to 3D printers:

https://blog.trimech.com/using-3d-printing-to-quickly-create-your-mold-designs

https://3dinsider.com/3d-printed-molds

https://www.mayku.me/blogs/news/how-to-design-for-vacuum-forming-and-mold-making-with-agustin-arroyo

Many materials can be cast using 3D printed molds with the right coatings, materials and settings, including metal:

https://www.matterhackers.com/articles/using-3d-printing-for-metal-casting-part-1

And this can print metal directly from a normal filament 3D printer:
>>1612939

>>1612935
More about stronger 3D printed parts:

https://www.fabbaloo.com/blog/2017/7/24/six-ways-to-strengthen-3d-printed-parts

This is provided as a service, but still is an option:

https://www.fabbaloo.com/blog/2017/7/7/the-rise-of-electroplated-3d-printed-parts
>>
>>1614005
More about 3D printing and casting:

https://www.youtube.com/watch?v=NBxp-9n_xjg

https://blog.zmorph3d.com/3d-printed-pva-molds-metal-fluid/

https://www.makergear.com/blogs/stories/casting-metal-parts

https://www.instructables.com/Aluminum-Castings-Created-Directly-From-3d-Printed/

https://hackaday.com/2018/02/25/casting-metal-parts-and-silicone-molds-from-3d-prints/

https://makezine.com/projects/guide-to-3d-printing-2014/metal-casting-with-your-3d-printer/

Glass is another material with similar techniques:

https://www.shapeways.com/blog/archives/38008-bronze-age-meets-digital-age-art-tim-belliveau.html
>>
>>1614012
YouTube recommended this edgy video (and many others), but you know who owns it.
>>
>>1611180
Most of those materials are also inspired by civil engineering, besides their use in marine and aerospace.

https://www.youtube.com/watch?v=2OUgqlzDIrw
>>
>>1611180
It seems nylon reinforcements were used in the some Corvette models made of fiber glass:

Study on mechanical properties of epoxy and nylon/epoxy composite

https://www.sciencedirect.com/science/article/pii/S2214785317331802

Nylon-Reinforced Polyethylene Film

https://www.professionalplastics.com/Nylon-Reinforced-Polyethylene-film

This material was also mentioned:

https://en.wikipedia.org/wiki/Sheet_moulding_compound
>>
>>1611180
Electric 'HIPERCAR' roll cage

https://compositebraiding.com/projects/roll-hoop-electric-car/

We were challenged to manufacture a new, lightweight roll cage for the electric HIPERCAR, to replace the existing roll cage made from steel. The new structure had to be as strong as the steel one, perform just as well in load tests, and have a similar failure mode.

We created a new thermoplastic-based composite roll cage, which was:

- Over 52% lighter than the existing steel structure
- Just as stiff and strong
- Superior in NVH (noise, vibration and harshness) performance
- Proven to have a similar failure mode to steel.

For this project, we replicated the geometry of the steel structure with composites (a ‘black metal approach’), so we could prove that performance improvements were caused by the material change.

If we redesigned the structure specifically for composite manufacturing, we could make further improvements in strength, stiffness and weight.

More about the car:

https://www.autoblog.com/2020/02/04/ariel-hipercar-hybrid/

Maybe this could be embedded into a composite car monocoque somehow.
>>
>>1614202
Another nylon sheet:

https://www.jm.com/en/advanced-composites/ap-nylon-composite-sheets/

http://compositeslab.com/composite-materials/reinforcements/

New Fibers: Polyester and nylon thermoplastic fibers have recently been introduced both as primary reinforcements and in a hybrid arrangement with fiberglass. Attractive features include low density, reasonable cost, and good impact and fatigue resistance. Although polyester fibers have fairly high strengths, their stiffness is considerably below that of glass. More specialized reinforcements for high strength and high temperature use include metals and metal oxides such as those used in aircraft or aerospace applications.

https://onlinelibrary.wiley.com/doi/abs/10.1002/pc.750080407

The potential of a nylon 6 fiber was evaluated for composite applications involving rigid polyurethane systems. A study showed that the use of COMPET N, a nylon 6 based fiber surface treated to enhance wetout and adhesion, in an ISP polyurethane system results in composites with higher impact values and lower weight than those reinforced with glass fiber. A 2 percent loading of COMPET N matt increased impact values by more than 300 percent over an unreinforced control while a 3 percent loading of glass matt resulted in increases of less than 100 percent. A drop impact test showed COMPET N fabric reinforced composites to absorb twice as much energy as an unreinforced and glass reinforced composite without major damage. These advantages have also been observed in COMPET N/Glass hybrids, in which layer orientation can be used to produce composites with specific properties.

...

Additional property benefits such as improved impact fatigue and decreased stress cracking have also been observed in nylon 6 reinforced composites resulting in the consideration of these materials for a wide range of applications.
>>
>>1611182
More about different types of fiber glass and the role of carbon or aramid fibers:

https://www.boats.com/reviews/fiberglass-boatbuilding-creating-a-laminate/
>>
>>1611293
Nomex honeycombs are expensive (and maybe an overkill), but maybe the alternatives aren't:

https://www.globalspec.com/learnmore/materials_chemicals_adhesives/composites_textiles_reinforcements/honeycombs_honeycomb_materials

Article about cost and weight of many types of panels:

https://www.epoxyworks.com/index.php/comparing-cost-and-weight-of-flat-panels/

Video about composite cores, where to find suppliers, a simple method for building parts and strength evaluation:

https://www.youtube.com/watch?v=6QCpnvhKkl8

Fibers get weaker in steep angles, so corners need to be smoothed before they are applied. This would make the part even stronger.
>>
>>1614259
Fiber glass honeycombs:

http://ultracorinc.com/products/fiberglass
>>
>>1613739
More information:

https://www.researchgate.net/publication/326703739_Review_on_Natural_Fiber_Composites
>>
>>1613560
Another idea for foams:

Application of recycled carbon-fibre reinforced polymers as reinforcement for epoxy foams

https://www.sciencedirect.com/science/article/pii/S0301479720306988
>>
>>1613073
And this propulsion system may have no moving parts in the future:

A piezoelectric acoustic pump: Design, mechanism and characterization

https://ieeexplore.ieee.org/document/6293070

Acoustic pump

https://patents.google.com/patent/US4684328A/en

A review of acoustic compressors and pumps from fluidics perspective

https://www.sciencedirect.com/science/article/abs/pii/S0924424718303807
>>
>>1611180
Some troubles I found while researching about affordable composites for small land transportation:
> only extreme conditions are tested, for example when a small patch of the material breaks, this isn't enough to know how the material will behave during a typical use scenario
> there's no way to know if it's brittle, durable, if it can be exposed outdoors, how it handles frequent deformations and vibrations, ... easily, except for some uniform or pre-made materials with a data sheet
> very few fair comparisons regarding cost, weight and strength exist
> the sites of manufacturers and distributors rarely have enough useful information about why to pick the material, others are very hard to find, many materials that could be used come from other areas (such as art, civil engineering, ...) and it's hard to know about them or their details
> it seems there's no easy way to use CAD/CAM with composites and pick from all sorts of different materials, optimize structures using them for strength, easy of assembly, durability, ... either manually or automatically
>>
>>1614447
> materials and composites have different characteristics for each direction (out of plane, in plane, a certain directional in-plane axis, ...), "crash" behavior (some just fold like an accordion, such as certain glass and natural fiber composites, others burst into pieces and this include some carbon fiber composites), and there's no easy way to know this information
>>
>>1614241
Important facts about cores:

https://themarinesurveyors.com/cored-vs-solid/
>>
>>1613982
>>1614368
Mechanical behavior of carbon fiber composite lattice core sandwich panels fabricated by laser cutting

https://www.sciencedirect.com/science/article/abs/pii/S1359645412003655
>>
>>1614447
>>1614457
>>1614460
Also the materials require coatings, details to be careful about, assembly instructions, useful tricks... which are hard to find in an organized way. In IT, programming and other technological areas, this sort of complex problem with too many variables is usually backed by user supplied information in wikis, question databases and others, and this might be a solution here.
>>
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>>1614259
Also it seems the weakest spots in fiber pieces are the edges where they were cut, this is another reason using a core material is beneficial: you can make the fiber sheets fold themselves around the core in a continuous closed shape instead of having edges without any suficient contact surface to get high adherence.
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>>1613731
More futuristic stuff:

https://www.cambridge.org/core/journals/mrs-online-proceedings-library-archive/article/abs/bioinspired-approach-of-the-composite-materials-towards-the-active-health-monitoring-concept/5D302E15B4356579713F659D54C4EA5F
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>>1611180
Mechanics of composite sandwich structures with bioinspired core

https://www.sciencedirect.com/science/article/abs/pii/S0266353814000578

The sandwich composites with bioinspired core exhibits an increase of approximately 100% in flexural stiffness compared to that of sandwich with conventional foam core. The strength and volumetric energy absorbed are found to increase by approximately 10× and 14× from the sandwich with conventional core. These results validated using Palmetto wood as a source of bioinspiration for increasing the energy absorbing capability of sandwich composites.

Rods made of fiber glass are also commercialized:

https://cacomposites.com/rods/

More about bioinspired materials:

A review of impact resistant biological and bioinspired materials and structures

https://www.sciencedirect.com/science/article/pii/S2238785420319219
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>>1614288
>>1612405
Another candidate for composite cores:

https://en.wikipedia.org/wiki/Foam_glass
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>>1611293
>>1611985
>>1612405
>>1613096
>>1613099
>>1613505
>>1613507
>>1613513
>>1613560
>>1613731
>>1613982
>>1614368
>>1614490
>>1614497
https://www.cambridge.org/core/journals/mrs-bulletin/article/white-paper-reticulated-foams-expand-the-boundaries-of-cellular-solids/558E596EFBC5E94135DA660522ACB097

Picture a structure formed by fibers or ligaments that frames open cells. Such a structure would be lightweight, permeable, and shock-resistant while retaining the properties of the parent material. Polymer foams, used for insulation, cushions, and packaging materials, were perhaps the first man-made material to take advantage of the unique characteristics of cellular solids. Today, another type of foam, reticulated foam, made of either a ceramic (typically alumina, silicon carbide, or vitreous carbon) or a metal (typically aluminum, copper,
nickel, stainless steel, or zinc), provides an extraordinarily versatile material that can be engineered for particular properties and tailored for specific applications. Reticulated foams have a number of features that benefit research and design engineers across many industries. The interconnected lattice of continuous ligaments within the cellular structure provides greater strength than shorter fibers and also ensures uniform material characteristics throughout the structure.
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>>1613562
>>1613562
>>1613739
>>1614341
There are many other natural fibers that aren't being considered:

Characterization of new natural cellulosic fiber from Cissus quadrangularis root

https://www.sciencedirect.com/science/article/abs/pii/S0144861714004081

Characterization of a novel natural cellulosic fiber from Juncus effusus L

https://research-information.bris.ac.uk/ws/portalfiles/portal/132985373/CARBPOL_D_17_00639_Revised.pdf

Characterization of New Cellulosic Fibers Obtained from Zingiber Officinale

https://www.tandfonline.com/doi/abs/10.1080/15440478.2020.1764452

Ichu: New Natural Fibers for Composites and its Extraction Methodology

https://www.mrforum.com/product/9781945291838-75/

Characterization of New Natural Cellulosic Fiber from Heteropogon Contortus Plant

https://www.tandfonline.com/doi/abs/10.1080/15440478.2017.1321516
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>>1614259
>>1614288
>>1614461
Synthesis and characterization of natural fiber reinforced polymer composites as core for honeycomb core structure: A review

https://journals.sagepub.com/doi/abs/10.1177/1099636218758589

New advances in fiber-reinforced composite honeycomb materials

https://www.researchgate.net/publication/343128939_New_advances_in_fiber-reinforced_composite_honeycomb_materials

Maybe cellulosic composites are enough for honeycombs:
>>1613505
>>1613507

Carbon fiber honeycombs exist but they aren't popular:

http://ultracorinc.com/products/carbon

>>1614461
>>1613096
Cores can have lots of different structures besides foams and honeycombs:

https://www.researchgate.net/publication/317585097_Analysis_of_the_compression_behaviour_of_different_composite_lattice_designs
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>>1614654
https://journals.sagepub.com/doi/10.1177/073168449801700505

This research investigates the strength of composite lattice cylindrical and conical shells under axial compressive loads. The lattice structures are composed of circumferential and helical members, whose cross-sections are rectangular.

--

Carbon Fiber Composite Pyramidal Lattice Structures

https://www2.virginia.edu/ms/research/wadley/Thesis/KFinneganMS.pdf

(contains a good overview about hollow non-foam cores)
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>>1611180
Found something about increasing oxygen content for combustion engines:

https://www.sae.org/publications/technical-papers/content/932804/

Some methods for carrying hydrogen, such as hydrogen peroxide or metal powders, also release oxygen. And there are ways to chemically store oxygen:

https://en.wikipedia.org/wiki/Oxygen_storage
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>>1614683
It doesn't seem impossible to adapt some of those cores (or similar ones) using slightly modified shapes for tiling or easy manufacturing, then making them by yourself in case there are no suppliers.
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>>1614460
>>1614241
https://rein4ced.com/features

If it had a core material plus some reinforcement, combined with an optimized design, I doubt too much carbon fiber would be necessary.

Design And Manufacture Of Composite Bicycle Frame And Evaluation Of Compressive Properties Of ± 45o E Glass/Epoxy Composite With Different Introduced Defects

http://ijsetr.org/wp-content/uploads/2015/08/IJSETR-VOL-4-ISSUE-8-2793-2798.pdf
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>>1614896
>>
>>1614896
A proper composite frame (without carbon fiber, hopefully, or at least only a few sheets of it) would look somewhat like this: continuous shapes, few and rounded corners (but it could have a different shape overall), ...
Of course the volume, shape and many other parameters would look different.

Another example:

https://en.kunststoffe.de/a/article/article-265363
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>>1614913
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>>1614914
Or something like this but smoother.
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>>1611293
>>1611985
Thick foam with a single wrap of fiber glass:

https://www.youtube.com/watch?v=2ucOBHe_L7o
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>>1612459
It makes you wonder how this and those 3D printing methods can be combined:

https://all3dp.com/2/3d-printed-motorcycle-most-promising-projects/

For example, you can print a complex core structure, do some post-treatments then wrap it with fibers, or use those same complex shape heuristics (that makes everything look like a bone) in the foam/honeycomb/lattice/... cores, ...
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>>1614927
Similar idea for cars:

https://www.3dsourced.com/rankings/best-3d-printed-car/
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>>1611180
Metals can tolerate very frequent low amplitude vibrations, for example engine vibrations, without being damaged, but some composites can't.
A lot of the sandwich composites posted here are soundproofing, so using antivibration and a composite monocoque body (which is a single piece without dangling parts) would damper noise from both inside and outside the car:

https://isoflex.com.au/products/engine-mounts/

https://vibrasystems.com/engine-motor-vibration-isolator.html
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>>1615135
Example for a small electric motor:

https://www.youtube.com/watch?v=j8JqRkW0V88
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>>1611180
Pre-made carbon fiber parts seem to be affordable and convenient depending on the use:

https://www.graphitestore.com/Carbon-Fiber/Rods-and-tubes-Unidirectional

https://dragonplate.com/

And they can be used in any part of the composite: core, skin, reinforcement, ...
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>>1615286
Pre-made composite parts are used in construction, this supplier has carbon, kevlar, glass and hybrid pieces:

https://www.rockwestcomposites.com/
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>>1613769
>>1613783
Interesting material:

https://carbonfibergear.com/blogs/carbonfiber/what-is-texalium

https://www.seabase.eu/shop/hexcel-fibreglass-texalium-1266-6-oz-80-cm-silver/

https://www.seabase.eu/shop/hexcel-texalium-1266-6-oz-80-cm-carbon/

https://www.seabase.eu/shop/hexcel-texalium-1266-6-oz-80-cm-yellow/
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>>1614490
Another bioinspired material:

https://www.tandfonline.com/doi/pdf/10.1080/19475411.2018.1541145





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