Adams Assignments – Problem 4 – Steering geometry 2

Deliverables: Tune hardpoints to achieve pitch gradient targets.         Acceleration pitch gradient: ~2.25 deg/g         Braking pitch gradient: ~1.60 deg/g Plots from Adams showing the effect of tuning. Pitch is the front-and-rear motion of a car about an axis…

Brake steer Brake steer: -0.096deg/m Suspension toes out under braking. Traction steer Traction steer: 0.078deg/m Suspension toes in under traction force. Longitudinal wheel center recession under traction Longitudinal wheel center recession under traction force: 0.493mm/KN Longitudinal wheel center recession under braking…

Double wishbone assembly was selected and hardpoints were modified to achieve the target results. Caster angle Caster angle (Original): 5.37deg Caster angle (Modified): 4.00deg Effects: Steering effort is reduced, straight-line stability and jacking effect are slightly reduced. Caster moment arm Caster moment arm (Original):…

1. Total weight= 1900Kg Total mass front= 0.55*1900=1045Kg unsprung mass front=90Kg Sprung mass front=1045-90 =955Kg Total mass rear= 0.45*1900=855Kg Unsprung mass rear=60Kg Sprung mass rear=855-60=795Kg Sprung mass critical damping Front c=2*sqrt(Kr*ms) Kr=Ks*Kt/(Ks+Kt) =20*250/(20+250) =18.51N/mm c=2*sqrt(18.51*955)…

1. i) Fs=1.15 Hz Wheelbase=2700 mm= 2.7m Speed= 60 mph= 26.82 m/sec Time delay= 2.7/26.82= 0.1 sec Tf=1/1.15= 0.87 sec Tf=Tr+Tl Tr=0.87-0.1= 0.77 Fr=1/0.77=1.30 Hz Rear sprung mass frequency= 1.30 Hz ii)-ix) Front spring rate Kt=Ks*(MR)^2 Ks=Kt/(MR)^2 =245/(0.97)^2 =260.39 N/mm Rear spring rate Kt=Ks*(MR)^2 Ks=Kt/(MR)^2…

1. Graph styles, titles, labels. The Camber gradient curve of a double-wishbone assembly is plotted with a wheel travel of 100mm in jounce and 100mm in the rebound. Y-axis range is set to -3 to 3 and the design condition is set to 0.Title, subtitle, labels are changed to make the graph easy to understand. 2. Plot configuration…

1. Wheel rate is the vertical force acting on the tire per unit vertical displacement at the location along the spindle corresponding to the wheel centerline, measured relative to the chassis. Wheel Rate= Spring Rate * (Motion Ratio)^2 Spring rate is a measurement of the amount of force needed to compress a spring…

1. i) Caster: 5.38°    ii) Mechanical trail: 9.41mm    iii) Kingpin inclination angle: 10.01°    iv) Scrub radius: 32.35mm    v)  Kingpin lateral offset: 85.29mm     2. Given Pneumatic trail: 25mm Mechanical trail: 9.41mm Lateral force: 2000N Restoring moment:…

1. Instantaneous center (-850.99,239.11) 2. Roll center (800,-224.79)