Very nice coment from the teacher at approx 28:13 when he tells his students that he is very happy by noticing that his students are not being dampened their enthusiasm even in lunch time. That is because the lecture is interesting done by the teacher capturing and keeping the interest from his students. 👏👏👏
The rear wheel receive braking before the front, on vehicles that carry drum at the rear and disc at the front. This is done by a metering valve that is incorporated in the Combination valve. The emergency brake is independent of the foot operated brake, so some vehicle carry drum at the rear to facilitate the emergency brake only.
no.that inertial force is the resultant action force applied by the tyres.we considered the force applied by the ground on the tyre as tractional force which is the reaction of the ground in the forward direction.delambert force or the inertial force or pseudo force is also the resultant force but it is the action force.so we can not consider it during force balance eqn because it is a resultant force.i tried my best to explain but this is quite complicated.i hope it will help😊
for gradient θ, if we don't approximate cosθ=1 and if we instead take the actual value of cosθ, the sum of Wf and Wr would not produce total weight, W. Why is that?
also, if the braking force is being distributed to the front and back, then the maximum braking force we found for both front and rear, is it before or after distribution?
I want to know the load distribution regarding articulated vehicle, like 4X2 tractor trailer, capacity 35T or 40T. And how to calculate the position of the coupling on the tractor?
When Air resistance, traction force and rolling resistance act parallel to the direction of motion, how can they produce clockwise or anticlockwise moments which are perpendicular to the direction of their action
if we do cosider angle thita as small and neglect it,so we also have to neglect wsinthita and it will no more be the case of uphilling because during climbing,the magnitude of the angle is around 30 digree or more which cant be neglected.isnt it?
Hello. In the equation for maximum possible acceleration for either rear or a front wheel drive vehicle, the driving force 'F' is assumed to be constant in nature. However according to me the driving force F would remain constant only till the motor or driving body reaches it's peak power. After that, the driving torque and hence the generated driving force, would become a function of velocity and would continuously decrease. This is because the motor or driving body will then maintain the peak power to a constant value and keep on increasing the RPM till the vehicle reaches a terminal velocity. My question is, in the constant power mode mentioned above, the driving force F would be a function of angular velocity. In such a case, how do we calculate the maximum possible acceleration?
Can we calculate the tractive force with that equation: F = n*TotalGearRatio*Te/Rw with n = Pout/Pengine, Te = engine torque and Rw= Radius of the wheel Or another equation: F = n*P/(w*Rw) where P is the power output of the engine, n = Pout/Pin and Rw = Radius of the wheel and w= rad/s of the wheel
Hi, I have a small question. Professor has told the braking is carried out first on rear wheels and next of front wheels. What is the time difference between them to lock the wheels(front and rear)?
substitute F with mu*Wf and rearrange the terms. Finally you will end up with the equation "(1+(mu*h)/L)*Wf=(l2/L+(fr*h)/L)*W". You will get the value of 'Wf'. And finally as you are well aware that Fmax = mu * Wf. Substitute. You will get the answer as on 35:16. Thank you Ranjith
Why didn't he simplified equation 6 into 8? Why is there an "l" left on both numerator and denominator. Did I miss anything? Also he used a parenthesis and then a bracket, what confused me.
he did simplify 6 to 8 at 35:12 l is total length between the wheels. The way the equation is formed makes it easier to plug values. parenthesis, bracket was a mistake
no sir.actually dlambert force is basically the action that the wheel is putting on the ground and ground is giving its reaction in the form of tractional force.while taking the moments we just have to take the action forces not the reaction forces.the force which you are talking about is the reaction for that is ground is putting.so it has to be downwards.hope this will help.thanks☺
Hi, i have a simple question : can we couple the longitudinal and vertical(with modeling the pitch motion ) dynamics ? i didnt found that in any litterature books. Thank you so much.
Fcos(theta) can be approximated as F but Fsin(theta) cannot be approximated zero as the other forces in that direction are of the same magnitude. But making Fcos(theta) as F doesn't cause much error
Very nice coment from the teacher at approx 28:13 when he tells his students that he is very happy by noticing that his students are not being dampened their enthusiasm even in lunch time. That is because the lecture is interesting done by the teacher capturing and keeping the interest from his students. 👏👏👏
The rear wheel receive braking before the front, on vehicles that carry drum at the rear and disc at the front. This is done by a metering valve that is incorporated in the Combination valve. The emergency brake is independent of the foot operated brake, so some vehicle carry drum at the rear to facilitate the emergency brake only.
18:00 In the traction force equation you are missing the "rotational inertia factor", which has to be added as a negative force.
no.that inertial force is the resultant action force applied by the tyres.we considered the force applied by the ground on the tyre as tractional force which is the reaction of the ground in the forward direction.delambert force or the inertial force or pseudo force is also the resultant force but it is the action force.so we can not consider it during force balance eqn because it is a resultant force.i tried my best to explain but this is quite complicated.i hope it will help😊
Robs Tech Channel
Sir,how to calculate the load transfer during retardation after the application of brakes
for gradient θ, if we don't approximate cosθ=1 and if we instead take the actual value of cosθ, the sum of Wf and Wr would not produce total weight, W.
Why is that?
The sum of Wf and Wr would produce the Wcos theta component which is normal to the road surface (assuming no acceleration perpendicular to road).
great lecture on longitudinal dynamics
please upload more videos on automobile engineering on other topics too.
Hi,
Can you please share the link for the difference between Longitudinal Dynamics and Lateral Dynamics?
also, if the braking force is being distributed to the front and back, then the maximum braking force we found for both front and rear, is it before or after distribution?
I want to know the load distribution regarding articulated vehicle, like 4X2 tractor trailer, capacity 35T or 40T.
And how to calculate the position of the coupling on the tractor?
When Air resistance, traction force and rolling resistance act parallel to the direction of motion, how can they produce clockwise or anticlockwise moments which are perpendicular to the direction of their action
if we do cosider angle thita as small and neglect it,so we also have to neglect wsinthita and it will no more be the case of uphilling because during climbing,the magnitude of the angle is around 30 digree or more which cant be neglected.isnt it?
I'm also having the same doubt....if u found the solution means please reply me
seems like he is just simplifying the rolling resistance equation only
wonderful lecture.. can we have some vedios on three wheeler dynamics
.
Hello. In the equation for maximum possible acceleration for either rear or a front wheel drive vehicle, the driving force 'F' is assumed to be constant in nature. However according to me the driving force F would remain constant only till the motor or driving body reaches it's peak power. After that, the driving torque and hence the generated driving force, would become a function of velocity and would continuously decrease. This is because the motor or driving body will then maintain the peak power to a constant value and keep on increasing the RPM till the vehicle reaches a terminal velocity.
My question is, in the constant power mode mentioned above, the driving force F would be a function of angular velocity. In such a case, how do we calculate the maximum possible acceleration?
I have one concern, why is the clockwise moment taken positive, when according to the convention it should be taken negative?
Can we calculate the tractive force with that equation: F = n*TotalGearRatio*Te/Rw with n = Pout/Pengine, Te = engine torque and Rw= Radius of the wheel
Or another equation: F = n*P/(w*Rw) where P is the power output of the engine, n = Pout/Pin and Rw = Radius of the wheel and w= rad/s of the wheel
Hi,
I have a small question.
Professor has told the braking is carried out first on rear wheels and next of front wheels. What is the time difference between them to lock the wheels(front and rear)?
where does he mention such a time difference?
would a complete rear braking system undergo weight transfer?
Why we considering L2 for Wf
what is Ff and Fr in the eq
if we consider cos thetha equals 1 shouldnt sin thetha equal 0 then?
35:16 can anybody tell me how he arrives at the rearrangement after subbing 6 into 8? For instance, where did the F from eq. 6 go?
substitute F with mu*Wf and rearrange the terms. Finally you will end up with the equation "(1+(mu*h)/L)*Wf=(l2/L+(fr*h)/L)*W". You will get the value of 'Wf'. And finally as you are well aware that Fmax = mu * Wf. Substitute. You will get the answer as on 35:16.
Thank you
Ranjith
Thank you so much!!
Thank you so much bro!
A.Naga Ranjith Kumar thanks a lot
do dry tyres have rolling resistance
If the tyre material is not visco elastic then no rolling resistance will be there
If the tyre material is not visco elastic then no rolling resistance will be there
Why didn't he simplified equation 6 into 8? Why is there an "l" left on both numerator and denominator.
Did I miss anything?
Also he used a parenthesis and then a bracket, what confused me.
he did simplify 6 to 8 at 35:12
l is total length between the wheels. The way the equation is formed makes it easier to plug values.
parenthesis, bracket was a mistake
Can I know which textbook is being used for the course?
I want to know as well ...
Thomas d Gillespie fundamentals of vehicle dynamics
if the car is going uphill , ma or (w/g)a should be upwards , so while counting Wf , it will be in anti-clock wise direction... am i right?
ma is a inertia or D'Alembert force, which will be opposite to the direction of motion (in general)
no sir.actually dlambert force is basically the action that the wheel is putting on the ground and ground is giving its reaction in the form of tractional force.while taking the moments we just have to take the action forces not the reaction forces.the force which you are talking about is the reaction for that is ground is putting.so it has to be downwards.hope this will help.thanks☺
Whats the value of "mu" we should consider while calculations..??
all the forces in the free body diagram are o.k why again extra W/g*a mentioned in the diagram
He rewrites m like W/g (W=mg -> W/g=m) that is all!!
where is that Pseudo Force gone ?
the people handling the camera are selvam, robert, kartikeyan, ramkumar, ramganesh, sathiaraj
Respectfully F-Y All
@@siddhantsarraf 😂
@@abhiyantrik7189 seriously bro I'm trying my level best to concentrate but this cameraman is 😭
@@siddhantsarraf I get u.
Meri samvednaye aapke sath hai 😔.
how to find retardation when brake is applied
and how to find braking force
waiting 4 ur answer
Hi, i have a simple question : can we couple the longitudinal and vertical(with modeling the pitch motion ) dynamics ? i didnt found that in any litterature books. Thank you so much.
Lotfi Zeghmi yes you can do that by using a third damper
Or an anti pitch bar
please fire the videographer! Why is he constantly moving the camera ? Just put in one angle and focus on the board!
why did you care, lol. You want good cinema, go for Netflix.
@@gejost idiot its very problematic to study like this
Sir you assume cos(thita)≈1 that means the (thita) is very close to zero. So why we didn't write sin(thita) as zero.
Fcos(theta) can be approximated as F but Fsin(theta) cannot be approximated zero as the other forces in that direction are of the same magnitude. But making Fcos(theta) as F doesn't cause much error
Fcos(theta≈90)differential coefficient is 0，but Fsin(theta≈90)differential coefficient is 1,so Fsin(theta) cannot be approximated zero.
(theta≈0 sorry
wt is wf
Wf = Normal reaction on front tyre
14:44 left side of screen, thank me later :p
I'm a mechanical engineer
42:30
I don't feel like he is that good of a teacher. He is great at the subject but not at teaching.
Worst Cameraman
how take the direction anticlockwise or clockwise