SUSPENSION TUNING MODULE (STM)
DYNATUNE SUSPENSION TUNING MODULE is an ulterior development of the Standard Ride Feature Tool in DYNATUNE R&H and comes as a powerful standalone tool. In STM do exist interactions between Front & Rear Body and NonLinear damping is more accurately represented by instantaneous ForceVelocity Gradients of the measured damper curve for the complete damper velocity range. Furthermore, by switching from a linear Laplace Transformation to a fully nonlinear numerical integration/differentiation of the ride equations, the tool allows a lot more indepth analysis of the spring/damper/suspension system and provides  with respect to the Standard Ride Tool in DYNATUNE R&H  more detailed results both in the Time, as in the Frequency Domain.
The tool comes with a "Control Section Panel" with convenient Scaling Factors for Spring Rates and Damper Jounce & Rebound Force Velocity Curves, allowing very quick optimization cycles. driven by the DYNATUNE philosophy to achieve maximal results with the absolute minimal amount of input data.
The tool is based on a standard MS EXCEL ® workbook and does use next to the standard workbook functions, also some additional custom written VBA code for the "live" Fast Fourier Transformation in the Frequency Transfer Function Algorithm.
NOTE: DYNATUNE SUSPENSION TUNING MODULE (STM) IS NOT INCLUDED IN ANY OTHER DYNATUNE TOOL. IT COMES AS A STANDALONE TOOL ONLY.
The tool comes with a "Control Section Panel" with convenient Scaling Factors for Spring Rates and Damper Jounce & Rebound Force Velocity Curves, allowing very quick optimization cycles. driven by the DYNATUNE philosophy to achieve maximal results with the absolute minimal amount of input data.
The tool is based on a standard MS EXCEL ® workbook and does use next to the standard workbook functions, also some additional custom written VBA code for the "live" Fast Fourier Transformation in the Frequency Transfer Function Algorithm.
NOTE: DYNATUNE SUSPENSION TUNING MODULE (STM) IS NOT INCLUDED IN ANY OTHER DYNATUNE TOOL. IT COMES AS A STANDALONE TOOL ONLY.
ANALYTICAL MODEL
The DYNATUNE STM Fully Dynamic Ride Model  which is being used for numerical calculating of the response of the vehicle to a road input signal  exists out of 4 DOF / 3 PART (bicycle) model with a Sprung Body, Unsprung Masses and (linear) Springs & (NonLinear) Dampers. The Sprung Mass is connected to Front & Rear Spring & Damper systems. Wheels are connected to ground each via a Tire Spring and Tire Damping (which is calculated out of the number for % critical tire damping input parameter).
The differential equations of motion are being solved in the time domain by numerical integration/differentiation with a step size of 0.001 sec. 
SPRING/DAMPER INPUT DATA
Next to the Damper Data some other Suspension Data have to be provided. Those parameters are the (linear) Spring Rate and the Motion Ratio of the Spring/Damper Unit to the Wheel. Tire Damping Characteristics have to be entered as % Critical Damping according to the usual definitions in Tire Modelling Literature.

Measured Damper Data are to be provided in the standard Force over Damper Velocity format  preferably in the standard speed range of 0 to 1572 mm/s used by almost every damper manufacturers. Different damper velocities however, can be handled without any problems, but the total number of data points is fixed and has to be filled up in the data table. Any operating points outside of the provided data will be linearly extrapolated based on the last two damper data points.

VEHICLE INPUT Data
The most important vehicle data are of course Vehicle Mass, Weight Distribution, Wheelbase and Pitch Inertia, since these parameters define  next to the spring and damper data  for the major part the ride behavior of the vehicle. The Pitch Inertia of the Sprung Mass is automatically calculated out of a generic xdistance deduction of the Steiner Part of the Unsprung Masses relative to the Center of Gravity of the overall Vehicle Pitch Inertia. 
ROAD INPUT SIGNAL
In RELEASE 8.0 DYNATUNE STM does provide in total 4 different types of road input signals, which are all frequently used in the automotive world to understand and optimize the ride oscillation of a vehicle.
The first 2 Signals have been especially developed for Analysis in the Frequency Domain and the other 2 Signals are commonly used for Analysis in the Time Domain. All signals can be adjusted in Amplitude & Time/Frequency Behavior and if desired the signals can be applied to one or two axles of the Vehicle.
The first 2 Signals have been especially developed for Analysis in the Frequency Domain and the other 2 Signals are commonly used for Analysis in the Time Domain. All signals can be adjusted in Amplitude & Time/Frequency Behavior and if desired the signals can be applied to one or two axles of the Vehicle.
FREQUENCY DOMAIN SIGNALS

TIME DOMAIN SIGNALS

2 Input Signals are available:
These signals are typically used on a 4 Poster Hydraulic Rig and can be executed in Bounce Mode or Pitch Mode. Due to the sinusoidal wave content, the results can be postprocessed with Fast Fourier Transformations.
The Linear Decaying Sweep Sine Function is representing a road signal with Linear changing Frequency Content (typically from 0Hz to 100Hz) and if desired, changing amplitude. The signal is typically used on a 4 Poster Hydraulic Rig and can be executed in Bounce Mode or Pitch Mode. Due to the sinusoidal wave content, the results can be postprocessed with Fast Fourier Transformations.
The Exponential Decaying Sweep Sine Function is representing a more artificial Road Input Signal with Exponentially changing Amplitude Content. The key feature of such a signal is the capability of creating an Input Signal with CONSTANT VELOCITY, allowing to finetune especially the Dampers in specific operating ranges.

2 Input Signals are available:
The Ramp/Step Function represents in effect a smooth 1/4 sinusoidal oscillation/step to a user defined Ramp Height. By setting the Ramp Length and Height & Vehicle Velocity, the Frequency Content of the Ramp is defined and displayed.
The Havsin Function represents a smooth 1/2 sinusoidal oscillation/step to a user defined Height, allowing to investigate the response of the vehicle oscillation to this input. By setting Length and Height of the Object & Vehicle Velocity, the Frequency Content of the ramp is defined and displayed. This particular information will help the user to relate the results from the Havsine Test better to the results from the Sweep Sine Test.
The Havsin Function is particularly useful for KERB Strike Events.

At this point it is worthwhile to mention that the Exponential Decay Signal does allow the Post Processing of Data for NONLINEAR Damper settings (KneePoints  Strongly Different Bump and Rebound Damper Curves. In the previous version of STM, the Fast Fourier Transformation (creating the Transfer Function) was forced to be executed with the averaged Jounce & Rebound Damping, mainly due to the fact that the Linear Decay Signal does contain at Higher Road Signal Input Frequencies more "Energy" than the Exponential Decaying Signal. This new signal has been a major step forward in analyzing nonlinear damping and should be used for all Standard Analysis.
CONTROL PANEL WITH SCALING FACTORS
After having entered all Vehicle & Suspension Data and after having selected the various Road Inputs, the user can basically optimize his suspension setting in the "Control Panel" by modifying the Scaling Factors for Front & Rear Spring Rates and Jounce & Rebound Damper Characteristics. The "Live Feedback" of the most important results  all located directly around the control panel  makes it easy to investigate alternatives and work towards the best compromise.
RESULTS
STM does provide 3 Main Area's of Analysis & Results.
 Frequency Domain Analysis & Results
 Time Domain Analysis & Results
 Classic Analytical & Ride Metrics
FREQUENCY DOMAIN RESULTS
THE SWEEP SINE RESULTS consist out of 3 Main Graphs and several Performance Metrics, all in the Frequency Domain
GRAPHS:
The Frequency Transfer Function describes the relationship between the Road Input Signal and the response of the Wheels & Body to this input. It basically shows, that if the road input at a Frequency of 3 Hz is for example 10mm, the Front Body would react with approximately 30mm vertical displacement and at a Frequency of 10 Hz the Front Body would react with approximately 1mm displacement. The presentation of such a chart is typically in a logarithmic scale, both for xaxis as for yaxis.
This Graph is in fact a Presentation of the Percentage Critical Damping over the Frequency Spectrum. It does show the Percentages of Critical Damping for Wheels and Body for a given Amplitude Input & Excitation Frequency. This allows a good overview of the amount of Damping in the System over the whole operating range.
A graph which displays the "Normalized Dynamic Wheel Load" for a given Excitation Frequency. This is the ratio of dynamic wheel load to static wheel load and when this value grows beyond 1, the wheel would in real life loose contact with the road. The graph does allow therefore a quick check if the road signal is suited for the vehicle or vice versa, the graph does show at which Excitation Frequency the wheels would start loosing contact with Ground.
METRICS:
The Key Performance Indicators/Metrics are:
GRAPHS:
 The Frequency Transfer Function Graph for Body & Wheel Movements.
The Frequency Transfer Function describes the relationship between the Road Input Signal and the response of the Wheels & Body to this input. It basically shows, that if the road input at a Frequency of 3 Hz is for example 10mm, the Front Body would react with approximately 30mm vertical displacement and at a Frequency of 10 Hz the Front Body would react with approximately 1mm displacement. The presentation of such a chart is typically in a logarithmic scale, both for xaxis as for yaxis.
 Moving Average Percentage Critical Damping
This Graph is in fact a Presentation of the Percentage Critical Damping over the Frequency Spectrum. It does show the Percentages of Critical Damping for Wheels and Body for a given Amplitude Input & Excitation Frequency. This allows a good overview of the amount of Damping in the System over the whole operating range.
 Dynamic Wheel Load Graph
A graph which displays the "Normalized Dynamic Wheel Load" for a given Excitation Frequency. This is the ratio of dynamic wheel load to static wheel load and when this value grows beyond 1, the wheel would in real life loose contact with the road. The graph does allow therefore a quick check if the road signal is suited for the vehicle or vice versa, the graph does show at which Excitation Frequency the wheels would start loosing contact with Ground.
METRICS:
The Key Performance Indicators/Metrics are:
 Dynamic Overshoot & Percentage Critical Damping Factors for Front & Rear Body at Resonance Frequency.
 Dynamic Wheel Load Indicator which does describe how close the Wheel Transfer Function remains to the Value "1".
 Maximum Dynamic / Static Contact Patch Load Ratio.
 Dissipated Energy in Dampers & Tires During The Test.
Time DOMAIN RESULTS
THE RAMP SINE / HAVSIN INPUT RESULTS consist out of 4 Graphs and several Performance Metrics, all in the Time Domain.
GRAPHS:
METRICS:
BODY:
WHEEL:
In RELEASE 8.0 in the Time Domain Analysis, the Ride Model does permit the wheel to lift off. The car can actually "jump". Performance Metrics are divided into Body and Wheel KPI's. All Body related KPI's describe objective measures for judging/describing the time behavior of the oscillation. The maximum vertical acceleration can be used for tradeoffs or to confront comfort aspects of variants.
Last but not least there the tool does contain graphical representation of Accelerations, Velocities and Displacements for the Center of Gravity.
GRAPHS:
 Time Trace of Displacements for Road, Wheel & Body
 Time Trace of Dynamic Contact Patch Load, Spring & Damper Forces
 Damper Operation Points
 Time Trace of Dynamic Spring Deflection & Damper Velocity
METRICS:
BODY:
 95% Decay Time
 Dynamic Overshoot
 Time to Reach Peak Overshoot
 Maximum Vertical Acceleration
WHEEL:
 Max / Min Contact Patch Load
 Contact Patch Load Integral
 Wheel Lift Time
In RELEASE 8.0 in the Time Domain Analysis, the Ride Model does permit the wheel to lift off. The car can actually "jump". Performance Metrics are divided into Body and Wheel KPI's. All Body related KPI's describe objective measures for judging/describing the time behavior of the oscillation. The maximum vertical acceleration can be used for tradeoffs or to confront comfort aspects of variants.
Last but not least there the tool does contain graphical representation of Accelerations, Velocities and Displacements for the Center of Gravity.
CLASSIC ANALYTICAL RESULTS
RIDE FREQUENCY & DAMPING RESULTS. DYNATUNE STM provides all the classically known numbers for Front and Rear Ride Frequencies and Percentage Critical Damping Charts for both "Jounce" as "Rebound" damper velocities corrected by motion ratio's and if applicable corrected by scaling factors. Plots are available both for Body as for Wheel damping. On top of that the location of the "Bounce" and "Pitch" Centers are being calculated and in order to optimize the vehicle setup Carpet Plots are provided showing the effects of a wide range of Front & Rear Wheel Rate Combinations on the location of those Centers with respect to the Front Axle of the Vehicle.

COMPARISON OF RESULTS
The Workbook does contain also a COMPARISON Sheet in which all key Parameters and Graphs for 2 Vehicles are listed allowing an easy back to back comparison of variants. Metrics which are more favorable are highlighted in Green.