Car Suspension System

CHAPTER 1
INTRODUCTION
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1.1 Background
A car suspension system is the mechanism that physically separates the car body from wheels of car. Performance of the suspension systems has been greatly increased due to increasing vehicle capabilities. To achieve a good suspension system of a car, we have to consider several performance characteristics. These characteristics deal with the regulation of body movement, suspension movement and the force distribution. The ideal suspension should isolate the body from road disturbances and inertial disturbances associated with cornering and acceleration or braking. Suspension must also be able to minimize the vertical force transmitted to the passengers for their

Stipulating the motion of two or more points expresses a shape. Stated in a different way, a shape is the movement of one point relative to all others. Motion is a vector quantity, which means that it has both a position and a direction associated with it. Motion at a point in a direction is also called a Degree Of Freedom, or DOF. All experimental dynamic constraints are obtained from dignified ODS’s.

3.2.2 Single Input (or SIMO) Testing
The most mutual type of modal testing is completed with either a single static input or a single static output. A moving hammer impact test using a single static motion transducer is a mutual example of single reference testing. The single static output is called the allusion in this case. When a single static input (such as a shaker) is used, this is termed SIMO (Single Input Multiple Output) analysis. In this case, the single static input is called the reference.

3.2.3 Multiple Input (or MIMO) Testing
When two or more static inputs are used, and FRFs are considered between each of the inputs and multiple outputs, then FRFs as of multiple columns of the FRF matrix are found. This is termed Multiple Reference or MIMO (Multiple Input Multiple Output) analysis. In this case, the inputs are the

One is the "half-arrow" sign convection. This defines the assumed direction of positive energy flow. As with electrical circuit diagrams and free-body diagrams, the choice of positive direction is arbitrary, with the caveat that the analyst must be consistent throughout with the chosen definition. The other feature is the "causal stroke". This is a vertical bar placed on only one end of the bond. It is not arbitrary. As described below, there are rules for assigning the proper causality to a given port, and rules for the precedence among ports. Any port (single, double or multi) attached to the bond shall specify either "effort" or "flow" by its causal stroke, but not both. The port attached to the end of the bond with the "causal stroke" specifies the "flow" of the bond. And the bond imposes "effort" upon that port. Equivalently, the port on the end without the "causal stroke" imposes "effort" to the bond, while the bond imposes "flow" to that port.

Table 4.1 Power variables in some energy domains
Energy Domain effort e symbol e unit (metric) e unit (imperial) flow f symbol f unit (metric) f unit (imperial)
Mechanical, translation Force F N lb Linear velocity v m/s ft/s, mph
Mechanical, rotation Torque Τ N•m ft•lb Angular velocity ω rad/s rad/s
Electrical Electromotive force V or u V V Current I or i A A
Magnetic Magnetomotive force em Flux rate ϕ
Hydraulic Pressure P Pa psi Volumetric