Front MacPherson Strut (2pc LCA)

In a front MacPherson strut (2pc LCA) suspension, the knuckle and wheel are located by a control arm and strut. The coil spring is part of the strut and acts between the strut tube and the vehicle body. The spring’s axis typically is not parallel to the strut, but is offset to minimize the bending moment in the strut.

Figure 1. Front MacPherson Strut (1pc LCA) Suspension with Steering

Model Use

The front MacPherson strut (2pc LCA) suspension system can be used in either a front half vehicle or a full vehicle models. The default geometry and mass approximate that of a passenger car or light truck, but the model and data can be revised to reflect any size vehicle, from a large truck to a scale model car.

Note:

The wheel body represents the mass and inertia of the tire and the rim.
The wheel hub body represents the mass and inertia of other rotating bodies such as a brake rotor, but not the half-shafts if the suspension is driven. The wheel hub and brake rotor have no associated graphics.
The wheel and wheel hub parts use the Wheel Center location as the center of gravity.

Tip:

A wide variety of combinations of suspensions and subsystems can be built using the Assembly Wizard. You are encouraged to build systems and understand the resulting model using the graphical user interface.
When building a new suspension model, build the model with all of the optional systems (stabilizer bar, etc) included in the model. Immediately turn off the systems using the Project Browser and run an analysis on the base suspension to ensure it solves properly. As data becomes available for the optional systems; activate those systems and populate them with data.

The image below shows the Project Browser view of the systems in a fully populated front suspension model. The Frnt macpherson susp (2 pc LCA) system has four “child” systems.

Figure 2. Browser View of a Front-Half-Vehicle Model Systems and Subsystems Employing a Front MacPherson Strut Suspension with Two (2) Piece Lower Control Arm

Points

Points locate the joints and bushings that connect the suspension bodies to one another. The image below shows the principal points for the front MacPherson strut (2pc LCA) suspension with a two piece lower control arm:

Note: The image above omits the left side of the suspension, points locating body centers of mass, and points that locate the optional subsystems (springs, dampers, bump stops and stabilizer bar) for clarity.

Bodies

The front MacPherson strut (2pc LCA) suspension is comprised of the bodies shown in the image below:

Note: Only right side bodies are shown (as the left side bodies are symmetrical), and the coil spring has been omitted from the image above for clarity.

The wheel hub body has no associated graphics and therefore is not visible in the image above.

Bushings and Joints

The table below describes the bodies, bushings, and joints for the front MacPherson strut (2pc LCA) suspension:

Note: The table omits the joints internal to the strut.


Label	Type	Body 1	Body 2	Point	Notes
Lower Ball Joint	Spherical	Knuckle	Lower Control Arm	Lower Ball Joint
Wheel Spindle	Revolute	Wheel Hub	Knuckle	Wheel Center
Wheel Hub Fix Jt	Fixed-Joint	Wheel	Wheel Hub	Wheel Center	When Spindle compliance is set to Yes, the joint type changes to universal and a bushing is superimposed to model the wheel bearing compliance.
LCA Bushing	Universal	Lower Control Arm	Subframe, Vehicle Body or Ground	LCA Bush	When the Compliant option is set to No, this joint compliance is turned "Off" and behaves as a pure universal joint.
Tension Strut Bushing	Universal	Tension Strut	Subframe, Vehicle Body or Ground	Tension Strut Bush	When the Compliant option is set to No, this joint compliance is turned "Off" and behaves as a pure universal joint.
Tension Strut to LCA	Spherical	Tension Strut	LCA	Tension Strut to LCA	When the Compliant option is set to No, this joint compliance is turned "Off" and behaves as a pure ball joint.
Strut Upper Bush	Universal	Strut Rod	Vehicle Body	Strut Rod Upper

The following image shows the location of the joints and bushings in the suspension:

Figure 5. Right Side Joints and Bushings - Front MacPherson Strut Suspension with Two (2) Piece Lower Control Arm

Similar Suspensions

front MacPherson strut (1pc LCA)

Rear MacPherson Strut