Difference between revisions of "Suspension Reasoning"

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[[Category:Suspension]]
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=Introduction=
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In table 1 we presented the importance of having a suspension and a damping system. With that in mind the next step is to select our spring and dampers. When choosing those a first common application is to define what are the goals for the suspension system. For example, are we trying to improve the tire’s mechanical grip or maintaining the vehicle’s aerodynamic platform?
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Introduction=
 
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For automotive applications, a vehicle suspension allows the controlled movement of the wheels relative to the vehicle body. In order to control it, passive, semi-active and/or active components are introduced. These enable the suspension system to adapt to various driving conditions. In most vehicles, this is achieved with a passive compliant structure (suspension). The vehicle suspension system consists of wishbones, springs, and shock absorbers to transmit and filter all forces between the body and road. If a vehicle has a passive suspension it will tend to oscillate under given inputs. To reduce the amount and duration of oscillation, some form of damping is required.
 
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WTF is table 1? is this copied from something?
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=Purpose of a suspension=
 
=Purpose of a suspension=
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The automotive industry uses different kinds of suspension systems. Important criteria are cost, weight, performance, packaging, manufacturing, kinematic properties and compliance attributes. A suspension and damping system can serve multiple purposes. Some of the reasons for having one are described in the table below.
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The automotive industry uses different kinds of suspension systems. Important criteria are cost, weight, performance, packaging, manufacturing, kinematic properties and compliance attributes. A suspension and damping system can serve multiple purposes. Some of the reasons for having one are described in table 1.
 
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|Purpose<br />
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|Description<br />
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!Description<br />
 
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|Improving driver and passenger comfort<br />
 
|Improving driver and passenger comfort<br />
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|A suspension acts as an interface between the the vehicle body and the road, reducing the passenger accelerations and movements. The accelerations of the vehicle body are also dependent on the amount of damping in the system.<br />
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|A suspension acts as an interface between the vehicle body and the road, reducing the passenger accelerations and movements. The accelerations of the vehicle body are also dependent on the amount of damping in the system.<br />
 
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|Reduce impulse forces<br />
 
|Reduce impulse forces<br />
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|Forced Vibration
 
|Forced Vibration
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|The vehicle can be excited in heave, pitch, roll and single wheel vibrations. This occurs particularly near the system’s resonance points and is due tothe consistent unevenness/bumpiness in the track. Damping can help to reduce the magnitude of this response.
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|The vehicle can be excited in heave, pitch, roll and single wheel vibrations. This occurs particularly near the system’s resonance points and is due to the consistent unevenness/bumpiness in the track. Damping can help to reduce the magnitude of this response.
 
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Latest revision as of 17:03, 27 March 2023

Purpose of a suspension

The automotive industry uses different kinds of suspension systems. Important criteria are cost, weight, performance, packaging, manufacturing, kinematic properties and compliance attributes. A suspension and damping system can serve multiple purposes. Some of the reasons for having one are described in the table below.

Purpose Description
Improving driver and passenger comfort
 A suspension acts as an interface between the vehicle body and the road, reducing the passenger accelerations and movements. The accelerations of the vehicle body are also dependent on the amount of damping in the system.
Reduce impulse forces
 A compliant structure helps to reduce the peak forces in the vehicle structure due to external impacts. This helps to improve vehicle reliability and allows lighter structural designs.
Static load distribution
 A suspension is a controlled compliant structure that can be used to distribute the normal load between the wheels.
Handling
 The suspension can be used to influence the handling of the vehicle by changing the tire normal load distribution. This is achieved by adjusting the suspension stiffness distribution, the suspension geometry or by controlling the aerodynamic platform. The vehicle damping can also be used to influence the transient vehicle balance by changing the damping coefficients.
Improve mechanical grip
 A suspension is compliant over bumps and impacts. This can help to reduce the tire load variation (TLV) seen at the tire-road interface. TLV has a large impact on grip due to the delayed response of the tire to load variations and due to the load sensitivity of the tire.
Aerodynamics
 The balance and effect of the aerodynamics can be influenced on ride-height sensitive vehicles with a suspension system. The position and orientation of the vehicle body is also dependent on the amount of damping in the system.
Transient Response The vehicle heave, pitches and rolls under inputs such as steering, throttle, brake application as well as large bumps and curb strikes, etc. Dampers help to control the response of these inputs.
Forced Vibration The vehicle can be excited in heave, pitch, roll and single wheel vibrations. This occurs particularly near the system’s resonance points and is due to the consistent unevenness/bumpiness in the track. Damping can help to reduce the magnitude of this response.
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