IMPORTANT: Before you can analyse ContactForce and ContactStress, you need to reconfigure the model so that it transfers the forces correctly between the cam and the follower. See: How to configure the Model for Payload Analysis. 
Camfollowers are manufactured from a limited number of steels [and some durable plastics], with rigid quality control and testing. Industrial Cams are manufactured by machine builders with different design and manufacturing quality standards and heattreatment procedures. Thus, even though a cam is an easier machine element to analyse, it is left to the machine designer to choose the correct material, heat treatment and lubrication method to give the cam an operationallife as required by their customers.
As a cam rolls under a camfollower roller (or a camfollower rolls over a cam), there is a contact force, and the cam and the camfollower become flattened, as does a car tire against a road surface. There is a socalled Hertzian Contact Stress, at, and beneath, the contact surface [Reference Hertz (1881) has done the hard work to derive the equations we need to calculate the stress when there is contact between two bodies that are conformal or nonconformal.
[H. R. Hertz, "Über die Berührung fester elastischer Körper (On Contact Between Elastic Bodies)" Journal für die reine und angewandte Mathematik 92, 1881 pp. 156171].].
The Hertzian Contact Stress calculations give the contactstress that is induced in flawless steels [no inclusions], and errorfree contact such that the contactload is constant across the cam and camfollower [See also Contact Assumptions, below]. The analysis also assumes that nothing is moving! MechDesigner is perfectly capable of calculating the Hertzian Contact Stress.
The Hertzian Contact Stress is sometimes called the 'Nominal ContactStress', especially with gearing calculations.
The RadiusofCurvature of the Cam changes as the cam rotates, while the Radius of the CamFollower is constant. When a Cam and cylindrical CamFollower Roller lightly 'touch' each other, their contact is a 'line'. When we increase the contact force, the cam and follower deflect [squash together, like a car tire against a road surface] and the contact line becomes a small rectangular across the width of the cam and camfollower.


The Hertzian Contact Stress beneath the Cam and CamFollower surface are a function of material properties and their radiiofcurvature. The parameters that are fixed for each body are:
The parameters that are continually changing as the cam rotates.
To calculate the Hertzian Contact Stress, at each point around the cam, it is useful to establish two 'equivalent' numbers for the material and geometry properties. Equivalent RadiusofCurvature $\frac{1}{{R}_{e}}=\frac{1}{{R}_{1}}+\frac{1}{{R}_{2}}$ Equivalent Elastic Modulus $\frac{1}{{E}_{e}}=\left[\frac{{1{\vartheta}_{1}}^{2}}{{E}_{1}}\right]+\left[\frac{{1{\vartheta}_{2}}^{2}}{{E}_{2}}\right]$ HalfWidth: $b=\sqrt{\frac{8\xb7F\xb7{R}_{e}}{\pi \xb7L\xb7{E}_{e}}}$ Mean Hertzian Stress: ${p}_{mean}=\frac{F}{area}=\frac{F}{2\xb7b\xb7L}$ Maximum Hertzian Stress pmax at the middle of the contact line ${p}_{\mathrm{max}}=\frac{4\xb7{p}_{mean}}{\pi}=\frac{2\xb7F}{\pi \xb7b\xb7L}$ Substituting for 'b', and rearranging, gives the Maximum Hertzian Stress, pmax, due to the ContactForce, F, as: ${p}_{\mathrm{max}}=\sqrt{\frac{F\xb7{E}_{e}}{2\xb7\pi \xb7L\xb7{R}_{e}}}$ Summary:
Note: Pmax is a compressive stress. It is often given as P0 in academic papers. 
Contact Stresses for Line Contact 
Poisson's Ratio Shear Stress The image to the left shows principal compressive stresses directly below the centreline of the contact. Note: The horizontal axis does NOT imply a dimension. It is only stress. HorizontalAxis : [Scale: 1.0 = Pmax ]
Verticalaxis : [Scale: 1.0b = half contact halfwidth, b]
Maximum Value of Shear Stress Shear Stress, τ45, is proportional to the Maximum Contact Stress, or Hertz Contact Stress. For line contact [cylinder on cylinder], the relationship is: ${\tau}_{\mathrm{max}}=0.3\xb7{p}_{\mathrm{max}}$ Depth of Maximum Shear Stress [Line Contact] $0.78\xb7b$ below the centreline of the rectangular contact 'patch'. The image to the left shows that the stresses, σz, σx and σy are ALL compressive, which reduce below the surface. Because the volume of contactstress is local to the contact, the surrounding material (the hinterland) does not want to move away to accommodate the expansion because the hinterland is not stressed. Because of symmetry of loading, it can be shown that the x, y and z, stresses are 'Principal Stresses'. 
Mohr's Circles for the Hertzian Contact Stress at a depth of 0.78b, which is the depth of the Maximum Shear Stress. 
At 0.78b below the surface, the Shear Stress is a maximum value [Line Contact]. The Principal Stresses, σx, σy and σz, at the depth of the Maximum Shear Stress, at a depth of 0.78b , relative to the maximum Contact Stress at the surface, are: σx(@o.78b) = 0.32Pmax σy(@o.78b) = 0.15Pmax σz(@0.78b) = 0.75Pmax These three values determine the Mohr's Circle diameters and their offset from zero stress.  see the image to the left. Maximum Shear Stress, τmax From the scale of the Mohr's circle, we can see that the Maximum Shear Stress[vertical axis] is half of the maximum difference to the Principal Stresses. [σz  σy ]/2= [075(0.15)] / 2 = 0.6 / 2 = 0.3 ${\tau}_{\mathrm{max}}=0.3\xb7{p}_{\mathrm{max}}$ 
In many cases, surface roughness, friction, lubrication, thermal effects, and residual stresses will result in conditions that invalidate the results from Hertzian analysis. Consequently, the stresses computed according to Hertz’s analysis are often regarded as guidelines that are correlated with experimental failure tests to find allowable stress limits. 
Shear Stress and Traction with Rolling Friction  image above Many elements in contact both slide and roll. For example, gearteeth, and flatfaced camfollowers sliding against a cam. There is always a coefficient of friction and thus a friction force. This results in tangential, normal and shear stresses that are superimposed on the stress caused by the normal Hertzian Contact Stress. These stresses are illustrated schematically in the image to the above. 

Orthogonal Shear Stress moving through the contact zone  image to left. The Hertzian Contact Stress exists beneath the two cylinders. The 'Maximum Shear Stress' is below the centreline. There is also a 'Maximum Orthogonal Shear Stress' to the left and right of the centreline. As the cylinders roll, the contact point moves from the left to right, The Orthogonal Shear Stress at each point in the rollers changes its 'sign' from 'positive' to 'negative', as shown in the plot of Orthogonal Shear Stress. The absolute value of Orthogonal Shear Stress is not as large as the Maximum Shear Stress. However, Orthogonal Shear Stress has a range [max – min] that is larger than the Maximum Shear Stress. The Orthogonal Shear Stress is believed to be significant with respect to 'subsurface Fatigue Cracks'. The Orthogonal Shear Stress is greatest at approximately:
