If you don't already know the meaning of "axially loaded" you will get lost quickly. Kept waiting for a hint, but it never came.

Wood grading matters. Its changed to allow junk lumber to be graded higher. From what i remember you werent allowed to to grade #2 or higher with knots 3/4” or larger on the edge.

Thank you, waiting for part 2

Very interesting! Elimination of stress risers in a novel way. I like it!

How long are the boards?

You need to take a strength of materials class. You are mixing up tension stress, bending stress, shear stress and localized bearing stress. Bending stress does not FLOW as you describe. Bending stress is ZERO at the center and high at the top and bottom of the beam. Shear stress is maximum at the center and zero at the outside edges, (VQ/(It). Tension is sort of uniform except your notch where you get an eccentricity and have both tension and bending. Put a hole in a beam and you get essentially two bending elements, at the top and bottom of the beam. For a short span, SHEAR stress, not bending stress, is controlling. Excellent video making, just wrong.

Informative, useful, interestingly presented!!! Thank you!!!

Awesome ❤❤❤

i would say no. but i will watch

What's the software used for the FEM?

Shapes really control the strength and stiffness of bending type elements.

Hi I need the book please

I Love you

still trying to work out the different types of forces. I'm trying to design a truck bed, and originally I was gunna use channels and L beams, cuz you gotta fit wrenches and fuel lines in there. But truck frames twist. So, I'm trying to figure out whether its better to go with the flow, or resist it. Stiffening the bed with beams that resist twist would support loads better. But letting the truck flex puts less stress on said beams and helps offroad performance. What I don't want, is for a beam that doesn't like twisting, to get twisted.

Bravo kudos 👏, this video properly summarises the entire RCC shear design in Eurocode and text books in just under 9 minutes 😊

Also you have to take into account that wood is basically a bundle of straws tightly packed and glued to each other. This means that when they are subjected to deformation there has to be room for the straws to bend into.

Really very well explained.

When you order a 2×4 and don't have the right measurements, return them! Look for the real deal cuz its stronger and better

For the sake of science, how do you know for the 3-hole beam, the center hole is as large as the 1-hole beam? Maybe you accidentally cut it slightly smaller, or smoother?

Thank you

Great video and information, thank you.

San Francisco here. Our Millennium tower downtown is quite a notorious example of differential settlement, for lack of a better definition. That part of SF is fill-over-Bay mud, with most builders needing piles deeper than 200’ before hitting something dense enough to carry towers similar in height/weight. The millennium group however only went down an average of 80’. A 10’ mat on top of that before the building started. I think it settled about 17” on two sides with a 12” lean? Don’t quote me on that. They ended up drilling more piers along the lower sides, over 200’ deep and attaching to the existing footing. The settlement had gotten so bad the windows started cracking, and elevator was closed for precaution, utilities were nearly disrupted. Significant cracks along the retaining walls in the underground parking/basement areas, with severe rebar corrosion and spalling concrete. It’s bad. All this because the developers wanted to save a little cheddar. Ended up costing them more for the ‘fix’. Ongoing saga. Differential settlement is a big issue here in the Bay Area, which I’m extremely thankful for considering I own a small but growing underpinning/foundation repair company

​​@sandervanderkammen9230 Obviously it's always very important to note the relevant facts. ​​ Kharzeestan Krappenz DiktorBummer Jurkzxoffenz etc and co - they should all note good with much awe & extreme wonder. *UPDATE MORE BREAKING NEWS ETC* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% The Comet was designed with military use in mind, Nimrod work started at De Havilland in 1953. The committee did not find hundreds of fatal flaws or evidence of design defects, structural defects, defective materials or shoddy workmanship. Ripstop provision was included. Claimed incidents did not involve cracks starting from window corners. The engine & engine intake position had advantages, were not flaws or fatal flaws & were not the cause of any incidents involving any Comet or Nimrod aircraft. Nearly all changes before the Comet 4 were just in case or were previously scheduled improvements. Bow-wing & the 707 story (see b-47 wing folding incidents) is the result of global economics & the well protected & very large domestic US airliner market & active support from the UK with for instance proposed competing airliners from Vickers & DH being blocked by the UK government at the time, cheap & nasty was the requirement with large scale production capability in one place. The 707 was of course a much larger aircraft which as a stressed skin metal airframe aircraft would require a thicker skin anyway. They got lucky at the time essentially. Bow-wing is the result of the large & well protected US domestic airliner market The fate of De Havilland was due to Govt policy Aerospace sector rationalisation & global economics, it was nothing to do with the Comet. A comprehensive, thorough & protracted testing program was carried out on the prototype & it's assemblies. Of course the Comet did indeed have Ripstop stop provision. De Havilland (Of England) Comets were not grounded after 1970 due to structural problems. *_It's interesting that some of the aircraft on the list should really have been noticeably safer than the Comet due to being a similar type but of much later design & manufacture but they definately were not safer._* How things were back then - *_Accident losses - % of aircraft built._* DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Vickers VC10 UK 5% *_The DH Comet had better safety than or similar safety to many other commercial passenger aircraft of a similar era_* Douglas DC-1 99% Douglas DC-2 47% Douglas DC-3 30% Douglas DC-4 26% Boeing s300 72% Boeing 307 70% Boeing 247 48% Boeing 707 20% Lockheed L-049/149 Constellation 30% Lockheed Electra Turboprop 29% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Sud Aviation Caravelle 15% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% A comparison of more recent aircraft. Accident losses comparison examples. 1970s - 1980s % of total Aircraft built Similar aircraft type, date / decade, useage, size. Biz Jets BAe-125-800 1.7 % Beechcraft Beechjet 400 2.2 % Cessna 550 Citation II 7.1 % Learjet 35 / 36 12 % Beechcraft 1900 6% Dassault Falcon 10 11.5% Aérospatiale SN.601 22.5% Medium size jets / Turboprops. BAe-146 5.1% Fokker 100 6% McDonnell Douglas DC-9-30 9.5% Fairchild FH-227 30% McDonnell Douglas DC-8 14% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Beechcraft, Fokker, McDonnell Douglass, Learjet, Fairchild, Aerospatiale, Canadair, Convair companies defunct. All Comets, including some Comet 1s, had full civilian use certification at some point after 1954, civilian use certification only being withdrawn after commercial flying stopped. Examples were flying until 1997 - one example did a signals research global circumnavigation flight series in 1993 via Australia virtually without a rest travelling 28000 miles, only had an ice warning indicator issue during the flights. *The DH Comet - World Firsts.* 1st gas turbine jet powered airliner. 1st high altitude 8psi pressurised full fuselage length passenger cabin airliner, not a trivial feature as structure strength required for pressurisation considerably exceeded strength required for normal flying stress. Nobody else had done anything similar before the Comet. The b-47 used 2 relatively small, heavily built pressurised modules (the aircraft where 6 had their wings fold up in 2 months while flying & some had their wings fall off while parked). The 1937 Boeing piston engined airliner pressurised passenger cabin was pressurised to 2 psi only - in fact that could easily be done as the normal unpressurized fuselage cabin structure strength for flying stresses only was all that was needed to be adequate so no significant weight increase issues needed addressing. 1st all hydraulically powered flying surface controls & actuators airliner with under carriage wheel disk brakes + ABS. 1st jet airliner to cross the Atlantic. 1st jet aircraft to do a world circumnavigation flights series. *Of course De Havilland had prior experience building many all metal construction airframe aircraft including thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland & we know the world's first all metal construction airframe airliner was built in England in the 1920s by Handley Page.* *_De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet._* The course of De Havilland & the general UK aerospace industry sector was not affected even slightly by the DH Comet. The course of national aerospace sectors obviously being similar & inevitable in many countries. *_Other interesting World firsts_* _World's first turboprop aircraft._ *Vickers Viscount Turboprop Airliner 1947.* *A 1945 Gloster Meteor Aircraft with Turboprop Gas Turbine Engine.* They might like to answer these questions. *Which airline has just ordered* *60 RR England Trent XWB Engines* *& What aircraft are the engines for?* _Bonus question for 10 points._ Which country has the *World's Highest Combined Per Capita* *Nuclear + Defence + Aerospace Sector Activity?* 👍 & 🙂 & of course 😎 indeed. *C H E E R S* & without doubt - _Toodle_ -PIP- *Old* *_C H A Ps._* This line left not blank intentionally. The next line is blank intentionally. . .... . ... ... ............... . . ... .. ... . ..... . ....... ........ ......... .... .... ............ ..... . Ivcxivcxivxcv cxcxcvccbxcv xcxiivxccxvcxv ccvvcvvvcvxcv vivcxiccvccvxx

​​​@sandervanderkammen9230 We feel we can shed some light on some common myths & misunderstandings repeated in many comments. ​ That's correct of course, at the time the Comet wasn't particularly dangerous. Agreed, that is indeed the case of course, The DH Comet was definitely not the worst engineering failure in commercial airliner history. Losses comparisons How things were in those days. DeHavilland Comet 4 UK 14% DeHavilland Comet all mks 17% Boeing 307 70% Boeing 247 48% Boeing 707 . 20% Boeing 707 20% Lockheed Electra Turboprop 29% Canadair CL-44 Turboprop 46% Convair CV-580 Turboprop 22% Convair CV-880 (ff 1959) 27% Convair CV-990 (ff 1961) 35% Of course De Havilland had prior experience building many all metal construction airframe aircraft & thousands of jet powered fighter aircraft that were primarily of metal construction with pressurised cockpits & jet engines built by De-Havilland. Yes, that's true, De Havilland carried out full stress analysis & engaged in a comprehensive & protracted testing program which is why key De Havilland people were happy to be aboard flying DH Comet aircraft. The Comet was the first airliner where stress due to pressurisation significantly exceeded flying load stress for a full length passenger cabin fyselage. We agree, that's correct, the DH Comet was the first passenger airliner with full length fuselage pressurisation at 8psi pressure differential. Handley Page built the world's first all metal construction airliner during the 1920s. In many cases earlier pressurised aircraft were larger, needed thicker fuselage skins due to flying stresses alone & had much lower pressurisation differential pressure. Of course ripstop provision was provided. The skin alloy used became unavailable at the time due to R & D at the manufacturers which resulted in the original alloy being discontinued. Later alloys had very similar properties. The skin thickness used for the Comet was used for similar size later aircraft. Frame spacing was not found to be too large & frame width was not found to be too small. Without doubt De Havilland did indeed always work to better than industry standards at the time, used up to date knowledge for the design & construction & no evidence of negligence or criminal negligence was ever produced in relation to the DH Comet. Obviously the DH Comet had no effect on the course of the aerospace industry in the UK. The UK now has the world's largest combined nuclear, aerospace & defence sectors per capita activity. That's correct, the investigation committee did not find hundreds of fatal flaws or evidence of design defects, structural defects, defective materials or shoddy workmanship. Indeed it is the case that ripstop provision was included. Claimed incidents did not involve cracks starting from passenger window corners. Pretty much all changes were just in case changes or were planned development modifications & improvements that were scheduled regardless of incidents. Obviously De Havilland designers knew all there was to know about metal fatigue at the time they designed the DH Comet. It is in fact true to say that the way airliners were built changed everywhere including in the US after the Comet incidents. We hope this helps, obviously. Cheers indeed of course 👍. . . .... ... ..... . .... .. .. ..... .... .... .... .....

4:08 "have to enter and exit at the same time" - no, they do not have to. That's a well-known mistake, it also appears in a wrong explanation for the lift force. They do not have to take same time. For example, the separator line that goes through the stagnation point takes infinite time to pass the stagnation points. And the closer you are to the separator the longer the delay. The correct statement is that the incoming flow is equal to the outgoing flow (measured in m³/s and for an incompressible stationary flow).

Best infm i sunscribed

6:37 the flow analogy definitely holds some weight!! Good one!!!!!!

“Why is the wood at my Home Depot worse than in my 100 year old house??” Because you don’t understand the world you inhabit, and thus have misguided expectations from poorly drawn conclusions

The older wood was better quality, but we did not need to optimize the sizing as much when we still had sprawling forests

why dosn't youtubes garbage algorithm spam this on my feed

I've read that the change in quality of lumber is due to a changeover in the logging industry from sustainable logging to clear cutting. I've read that this changeover happened in the 80s, and that it was because of the S&L scandal. The story goes that the S&L scandal was built on a bubble of fake construction projects, which caused a spike in demand for framing lumber, which caused the logging companies to switch to clear cutting. I read this about 20-25 years ago, the other day I tried to google on this to see if I could find something to confirm it, but of course all I found were conflicting stories.

Building codes for wright bearing needs to be revised as the people havw gotten overweight in the last 4 decades. If yiu watch a movie from 1970s or 1980s, you will ratelt see a fat petspn among syreet crowds but now over 30% are ovetweight.

Hello The Engineering Hub: 0:48 I'm not an engineer, but I'd put my money on the slower growing, much tighter grained (yet smaller) North American 2 x 4 being stronger.

Thank you for your video interesting. I would only use a 2x4 in wall application ,there's not enough depth for a floor joist .When building a wall 16 on center, blocking at halfway point. That wall will carry incredible amount of load

Wood quality is a huge factor. Wood with thick grains where grown fast and will have a lower strength. The majority of Wood in notth America is less then 20 years old. They cut the same area every 20 years or so. That Wood has very little strength compared to a natural tree that wasn't planted and had more time to get strong.

Google "suspension bridge that carries rail traffic" and there are 4 results when I looked

The upper and lower horizontal elements of the truss structures are not axially loaded, are they ? Also, the San Francisco Bay Bridge, a suspension bridge on the San Francisco side, carried light rail traffic (streetcars) in the 1930s and 40s

Wasn't this an issue with the Titanic?

Codes are set as a minimum standard. Mainly for safety reasons.

If, hypothetically, the Giant Pendulum were to fall, it could break through all floors until it hits the ground due to its weight and the force of the fall. Let that sink in.

That test was not valid because it had a knot in it The testing length should be free of knots

Old growth or 2024 Home Depot 2x4? Lol

I do a less scientific test on my channel, only comparing it to a true 2x4 that I made! I break the store bought by hand. You should try this test using one of mine

Torpedoes?

Yes, I am very interested in this type of stories.

That's never how a 2x4 is used, you have to use a 2x6 or 8 depending on several things but a 2x4 should only have downward pressure in a wall where they are 16 inches apart (in the US). This test is pointless and a waist of time. If your contractor is using 2x4 for your floor FIRE THEM.

You dragged this out to where you made it boring!

okay, thanks for the info! I'm running right now to drill as many holes as I can on my apartment building support beams!

Was this video intended to boring in order to sort out engineer prospects?? LOL