LOAD TRANSFER

LOAD TRANSFER

HAVE YOU EVER THOUGHT WHY COMMERCIAL VEHICLES HAVE DISC BRAKES IN FRONT WHEEL?

NOW LET US FIND OUT THE ANSWER TO THESE QUESTION.

FOR FURTHER DISCUSSION LET US TAKE FEW ASSUMPTION LIKE

1.       VEHICLE IS HAVING LATERAL SYMMETRY

2.       WEIGHT DISTRIBUTION IS 60:40 (FRONT:REAR)

3.       VEHICLE IS MOVING IN A LEVEL ROAD

                                                             

 

 

 LOAD TRANSFER CALCULATIONS  

       ACCELERATION AND BRAKING

WHEN WE ACCELERATE THE LOAD TRANSFER TO THE REAR WHEEL OF THE VEHICLE TAKES PLACE AND IN CASE OF BRAKING LOAD IS TRANSFERRED TO THE FRONT WHEEL. NOW WE WILL CALCULATE THE VALUE OF LOAD TRANSFER IN CASE OF ACCELERATION WITH THE HELP OF HALF VEHICLE MODEL IN SIDE VIEW.

                             

 

 

 

 

 

                             CORNERING OR LATERAL LOAD TRANSFER

WHEN THE VEHICLE CORNERS THEN THE LOAD TRANSFER TAKES PLACE DUE TO LATERAL ACCELERATION OF THE VEHICLE. NOW LET US CALCULATE THE VALUE OF LATERAL LOAD TRANSFER IN CASE OF CORNERING WITH THE HELP OF HALF VEHICLE MODEL IN FRONT VIEW.

SO WE HAVE SEEN FROM THE ABOVE DISCUSSION THAT WHEN A VEHICLE ACCELERATE THEN LOAD TRANSFER TAKES PLACE. MORE IS THE LOAD TRANSFER MORE IS THE NORMAL FORCE ON THE WHEEL ON WHICH LOAD IS TRANSFERRED AND HENCE MORE IS THE FRICTIONAL FORCE. THAT IS WHY VEHICLES ARE REAR WHEEL DRIVEN BECAUSE IN ACCELERATING ALONG A LINE LOAD IS TRANSFERRED TO REAR WHEEL AND SIMILARLY IN BRAKING LOAD IS TRANSFERRED TO THE FRONT WHEEL AND HENCE THE VEHICLE HAVE DISC BRAKES IN FRONT WHEEL.

FACTORS INFLUENCING THESE LOAD TRANSFERS ARE:

1.       HEIGHT OF CENTER OF MASS OR GRAVITY

2.       TRACK WIDTH

3.       WHEEL TRAVEL

4.       ACCELERATION OF THE VEHICLE

5.       MASS OF THE VEHICLE

DESIGN AND SKETCH

 

 

DESIGN

DESIGN IS THE PLAN ONE MAKES TO CONSTRUCT OR DEVELOP AN OBJECT OR A SYSTEM.

Another definition for design is a roadmap or a strategic approach for someone to achieve a unique expectation. It defines the specifications, plans, parameters, costs, activities, processes and how and what to do within legal, political, social, environmental, safety and economic constraints in achieving that objective.



DESIGNS ARE BASED UPON MATHEMATICAL CALCULATIONS AND THE SCIENCE BEHIND IT. DESIGNING IS NOT AN EXACT SCIENCE BUT IT IS THE MATTER OF USEFUL APPROXIMATION ONE TAKES TO MAKE HIS PRODUCT AS HE WANTS.

OPTIMUM DESIGN IS NOT POSSIBLE BUT WE CAN TRY TO TAKE IT NEAR OPTIMIZATION BY DOING THE ITERATIONS OF THE MATHEMATICAL CALCULATIONS BY TAKING NEW APPROXIMATION AND THE COMPARING THE RESULTS WE HAVE OBTAINED EARLIER. BEST PART OF DESIGNING IS THAT DIFFERENT PEOPLE MAKE DIFFERENT DESIGN OF COMMON PRODUCT BY USING COMMON SET OF MATHEMATICAL EQUATION. LIKE IF WE ASK FEW PEOPLE TO DESIGN A JUG THEN FEW OF THE MAY USE BROAD BOTTOMED DESIGN AND OTHER MAY USE NARROW BOTTOMED DESIGN IN BOTH THE DESIGN WE ARE LOOKING FOR THE STABILITY OF THE JUG BUT FEW MAY THINK THAT IT SHOULD NOT TOPPLE  EVEN WHEN IT IS SUBJECTED TO HIGH LEVEL OF JERKS AND OTHERS MAY NOT CONSIDER IT TO BE OF MUCH IMPORTANCE.

 

SKETCH

AS PER DICTIONARY A SKETCH IA A SIMPLY OR HASTILY EXECUTED DRAWING OR PAINTING, ESPECIALLY A PRELIMINARY ONE, GIVING THE ESSENTIAL FEATURES WITHOUT THE DETAILS.
SKETCHING IS NOT THE SCIENCE BUT ITS AN ART OF AN ARTIST TO RECORD OR DEVELOP AN IDEA FOR FUTURE USE.A SKETCH IS ENTIRELY BASED UPON ONES IMAGINATION AND HOW HE PERCEIVES THE WORLD AND OBJECTS(PERSON, PLACE, OBJECT ETC). SKETCHING IS CONSIDERED AS THE LANGUAGE OF AN ARTIST WHERE THE SKETCH ITSELF SPEAKS EVERYTHING.  IN HISTORY ALSO IT IS CONSIDERED AS ONE OF THE MOST BASIC LANGUAGE USE B HUMAN BEING BY DRAWING ON ROCKS AND WOOD.

DESIGNING APPROACH

HERE WE ARE TALKING ABOUT THE VEHICLE DESIGNING. FIRST AND FOREMOST WE HAVE TO UNDERSTAND THAT OUR VEHICLE WILL BE MOVING ON ROADS AND THE SECOND THING IS THAT WHAT ACTUALLY WE WANT TO MAKE A PERFORMANCE VEHICLE OR COMFORT VEHICLE.

PERFORMANCE OF A VEHICLE IS DECIDED BY LOTS OF FACTORS LIKE POWER, BRAKING, ACCELERATION, TOP SPEED, STABILITY ETC.
POWER LIMITED PERFORMANCE INCLUDES ENGINE,BRAKING, STEERING ETC.
FRICTION LIMITED PERFORMANCE INCLUDES TIRE AND TRACK
STABILITY LIMITED PERFORMANCE INCLUDE SUSPENSION, CHASSIS ETC.


A RACE CAR PERFORMANCE IS MAINLY DEPENDENT ON ITS ACCELERATION AND STABILITY CAPABILITY. TOP SPEED DOESN'T MATTER MUCH IN A CIRCUIT RACE AS A CIRCUIT CONSISTS OF LOTS OF TURNS WHERE WE HAVE TO BREAK, TURN AND THEN ACCELERATE AND ALL THIS THREE PROCESS MUST BE DONE IN LIMITED TIME INTERVAL SO AS TO GET AN ADVANTAGE OF MILLISECONDS IN A CIRCUIT RACE.

HOW TO PROCEED IN DESIGNING

HERE IS AN EXAMPLE HOW WE WILL PROCEED TOWARDS FINALIZING OUR SUSPENSION POINTS OF THE VEHICLE.

CENTER OF GRAVITY AND ROLL CENTER HEIGHT IS ASSUMED.
FROM THAT WE CALCULATE THE MAXIMUM LOAD TRANSFER.
THEN WE FIX A RIDE FREQUENCY.
FROM THAT RIDE RATE IS CALCULATED,
ANY MOTION RATIO IS SELECTED,
SPRING RATE IS CALCULATED FROM THAT AND THEN USING THE IDLE LOAD AND LOAD TRANSFER AT CORNERING WE CALCULATE THE COMPRESSION IN THE SPRING AND THAT IS MATCHED WITH THE GROUND CLEARANCE.
IF WE GET A REASONABLE DATA THEN WE STICK TO THAT OTHERWISE SOME APPROXIMATIONS ARE DONE AND AGAIN WE DO THE SAM ITERATION IN THIS WE CAN ALSO MOVE IN REVERSE DIRECTION BY ASSUMING A GROUND CLEARANCE OF OUR CHOICE.

SO WE CAN VERY WELL SEE THAT DESIGNING IS A TEDIOUS JOB WE ARE COMPELLED TO DO THESE ITERATIONS TILL WE ARE NOT GETTING SOME REASONABLE VALUES. MORE WE ITERATE BETTER WE WILL BE ABLE TO FIGURE OUT OUR VALUES.