วีดีโอ

Thank you 🙏🏽

You're welcome

Habe ich vorerst (noch) nicht geplant. Ich werde es mir aber notieren.

Freut mich zu hören!

This is just a notation I use to make the difference between a result and a condition clear. "=" ultimately means "is the result of something" and "=!" means "is a condition that we presuppose".

Each point on the gear is ultimately a superposition of the movement of the centre of gravity (which is the same for all points considered) and the rotational movement. The gear, and therefore the rotation, moves with the centre of gravity and not with the circumferential speed. The linear speed distribution (shown in blue) is thus shifted to the right by the amount of the centre of gravity speed. In fact, if the gear itself did not rotate around its center of gravity, which means that a marked tooth on the gear would always be at the 12 o'clock position as the center of gravity moves on a circular path, then every point on the gear would actually move at the same speed, regardless of the radius. The speed at each point on the gear would be the speed of the center of gravity.

@@tec-science Isn't Vc (at the center of gravity of the planet gear) equal to Nc (angular velocity of carrier) times the distance between the center of carrier arm and the center of planet gear? In the same way, will the velocity not vary throughout the planet gear (I am talking only about the velocity due to rotation of carrier arm. The velocity indicated in green colour in the video)?

I think I understand your problem. But the linear velocity distribution of the planet gear has its center of gravity as its reference. The linear velocity distribution is related to this center of gravity. If this center of gravity now moves with the velocity vc (velocity of the carrier), then the entire linear velocity distribution is superimposed by this velocity vc. The entire linear velocity distribution is shifted by this amount. Therefore, the velocity vc is added to the entire velocity distribution regardless of the radius considered on the planet gear.

@@tec-science I understand your explanation. You have superimposed the velocity due to rotation of planet gear due to its rotation about its center of gravity (blue velocity vectors)and the velocity due to the velocity of the center of gravity itself. However, will not the velocity Vc be constant (green velocity vectors) throughout only if the gear was moving in a straight line? In this case, the planet gear is undergoing revolution about the carrier center, not translation in a straight line. So, the green velocity distribution should also linearly vary (instead of being constant, as shown in the green distribution). Please correct me if I am wrong.

th-cam.com/video/MQ9EwtqR9gU/w-d-xo.html I think your mistake is that when you superimpose the movements where the planet gear is initially assumed not to rotate, you think that the planet gear is firmly locked to the carrier. However, with this assumption, the planet gear rotates once around itself with each revolution of the carrier (this false assumption leads to the coin rotation paradox). When it is said that the planet gear does not rotate while the carrier rotates, this means that, for example, a marked tooth on the gear that is at the 12 o'clock position is there for the entire rotation (see the animation in the link). There is no linear speed distribution, but the planet gear has a constant speed along its entire diameter (shown in green).

β refers to the rotation of the planet gear when the sun gear is stationary. Now, however, the movement of the sun gear is superimposed on this and turns the planet gear backwards, so that the planet gear now effectively covers the angle 𝝳.

Gern geschehen!

On my website you will find several articles on the subject of fluid mechanics. I can't say when I'll get around to making a video about this. But it will certainly take some time.

I have already created a video on the subject of undercutting: th-cam.com/video/bol1U0BHcew/w-d-xo.html I hope this helps.

Das freut mich!

You're welcome!

like I said: th-cam.com/video/bol1U0BHcew/w-d-xo.html

Thank you!

Danke für das Lob!

I'm glad you asked, otherwise I wouldn't have looked into this wonderful operating principle.

Thank you very much!

Vielen Dank!

🙏🏽

Thank you for the appreciation, indeed a lot of work. 🙏🏽

Danke. Ja, da hat sich in den letzten Monaten einiges getan was die KI Stimmen angeht

@@tec-science Der Inhalt war natürlich auch wieder klasse. Kannte die Formeln nur im Englischen als Capstan-Equation, hier im Video als Anwendungsfall für spiellose Robotikgetriebe: th-cam.com/video/MwIBTbumd1Q/w-d-xo.htmlsi=w7pkTpvG_K86YctR&t=853

Danke 🙏🏽

See the video "Undercut of Gears"

I use Blender

... You mean like in centrifugal governor?

@@tec-science Yes...centrifugal an inertial governors...like Protell, Hartnell, etc

@@tec-science Yes...centrifugal and inertial governors....Hartnell, Proell, etc.

Thank you 🙏🏽

Thank you so much for your kind words! 😊 I really appreciate your support and encouragement. It's viewers like you who make all the effort worthwhile.

Thank you for the congratulations and for watching the video! I'm glad you enjoyed it. 😊 Unfortunately, I can't help you with Stata.

your're welcome 😊

Thank you. The formula should be correct because you need 2 times the tooth head plus the diameter of the reference circle.

Vielleicht wirst Du fündig im Video zum Verformungsprozess: th-cam.com/video/oB5GpN_ESzU/w-d-xo.html

🙏🏽

DANKE!

Thank you !

Actually, I have never had anything to do with RV gearboxes. I'm going to look into it and see if I can make a video about it. However, it may be some time before I get around to it.

At first I also thought that a belt drive is simply a belt that is placed around a pulley - that's it. Until you have to dimension such a thing yourself: rope friction equation, centrifugal forces, bending stresses, elastic slip, optimum belt speed, pre-tension, belt tensioner systems, etc. I will make a whole series of videos on this.

Danke fürs Feedback!

Thank you for the words of appreciation. I'm glad if I could help!

In general, ductile materials under tension form voids which then coalesce and lead to fracture. However, in highly ductile materials like gold, this behavior is modified due to the unique mechanisms of vacancy and nanocrack dynamics (see the paper www.jstage.jst.go.jp/article/matertrans/47/2/47_2_298/_pdf/-char/en) 1. Vacancy Dynamics: In highly ductile materials, vacancies play a significant role in deformation. Gold, for example, generates and transports vacancies extensively during deformation. 2. Nanocrack Fragmentation: Nanocracks in gold contribute to void nucleation and growth, but due to the high mobility and continuous migration of these nanocrack fragments to the specimen surface, the voids do not coalesce centrally but rather along the length of the specimen. 3. High Internal Stress: The high internal tensile stress in materials like gold during low-speed deformation prevents the stabilization of voids at the center, promoting necking to a point instead. These factors combined suggest that the unique vacancy and nanocrack behaviors in highly ductile materials like gold lead to a deformation mechanism where the material necks down to a point without forming central voids, differing from the traditional ductile fracture process which typically involves central void coalescence. In essence, the high mobility of vacancies and nanocrack fragments in gold, coupled with the material's ability to sustain high internal stresses, results in the necking phenomenon observed in highly ductile materials.

highly appreciated

Why does the shear take place at a 45-degree angle? According to Schmid's law (check out the video) shear stress is maximized on planes oriented at 45 degrees to the axis of the applied tensile stress. This is because, under uniaxial tension, the maximum shear stress occurs on planes that are inclined at 45 degrees to the direction of the applied load. In a ductile material, plastic deformation is driven by shear stress, leading to significant deformation along these planes. In ductile materials, deformation typically occurs through the process of slip, where dislocations move along slip planes. These slip planes are oriented in such a way as to accommodate the shear stress. The alignment of these planes at approximately 45 degrees to the tensile axis facilitates this slip process, leading to the characteristic 'cup and cone' fracture. Will the shear angle not be different for different grains? Indeed, individual grains in a polycrystalline material may have different orientations, leading to variability in the local shear planes. However, the macroscopic fracture surface results from the collective behavior of numerous grains. While the shear angle can vary at the microscopic level within individual grains, the overall shear plane tends to align with the 45-degree angle where the average shear stress is maximized. Is the failure intergranular or transgranular in ductile materials? Transgranular Fracture: In ductile materials, the fracture is predominantly transgranular, meaning it propagates through the grains rather than along the grain boundaries. This occurs because plastic deformation, which precedes fracture, tends to be more uniform within grains, allowing cracks to traverse through them. Does the failure take place finally due to breakage of atomic bonds or completely due to slip? Combination of Mechanisms: The failure in ductile materials involves a combination of mechanisms. Initially, plastic deformation occurs predominantly through slip, where dislocations move and atomic bonds are temporarily displaced but not permanently broken. As deformation progresses and the material reaches its ultimate tensile strength, voids and micro-cracks form and grow. Final fracture occurs when these voids coalesce and the atomic bonds are irreversibly broken. Thus, the final failure involves both slip and the breakage of atomic bonds. Failure in Brittle Polycrystalline Materials In brittle polycrystalline materials, the fracture can be either transgranular or intergranular. The mode of fracture depends on the material's properties and the presence of impurities or weaknesses at the grain boundaries. In many cases, brittle materials tend to fracture along grain boundaries (intergranular fracture) due to the higher brittleness of these regions. However, in the absence of significant grain boundary weaknesses, the fracture may be transgranular. In brittle materials, failure typically occurs due to the direct breaking of atomic bonds without significant plastic deformation. The stress concentrates at flaws or cracks, leading to rapid propagation of the crack and cleavage along crystallographic planes. This cleavage involves breaking atomic bonds along specific planes, leading to sudden and catastrophic failure. Long story short: In ductile polycrystalline materials, shear takes place at a 45-degree angle due to maximum shear stress, and fracture is predominantly transgranular with a combination of slip and atomic bond breakage. In brittle polycrystalline materials, failure can be intergranular or transgranular, primarily due to the breaking of atomic bonds along specific planes without significant plastic deformation.

@@tec-science Thanks a lot...this was very helpful