Meshing and connection implementation for CCB using ANSA

AIM: Meshing and connection implementation for CCB using ANSA

METHODOLOGY: 

1. Import CAD model and geometry cleanup.
2. Mid-surface generation and set different PID with Thickness value.
3. Quality and Mesh parameter setup.
4. Meshing and Mesh correction.
5. Deploying weld and RB connections as per requirement. 

INTRODUCTION:

Cross Car Beam(CCB)

An ordinary automotive vehicle frame includes three pairs of vertical pillars as it is pictured in the top scheme of Figure.1, but depending on the class of the vehicle there may be some automobiles that have only two pairs and others that may have four. This study focuses on the front end of the vehicle, i.e., the only concern will be with the A-pillars, which are located on opposite sides of the body, between the engine compartment and the passenger compartment, typically enclosing the windshield. As part of the main body structure, the A-pillars are extremely critical for occupant protection especially in case of rollover accidents. Nonetheless, in the case of a side-impact crash is the cross-car beam, the element linking both A-pillars that will provide the desired stiffness to protect the passengers.

                                                                                 Figure.1 vertical pillar for the class of the vehicle

 The Cross Car Beam (CCB) is a component found in the front part of the vehicle, under the instrument panel (IP) and, is usually designed to support the steering column, the airbags, the instrument panel, and it can also support other systems depending on the complexity of the car. Apart from the support role, this component is also instrumental in the absorption of impact-energy, minimization of the steering wheel displacement in case of a collision, reduction of the overall cockpit vibration and, in providing greater strength and control of the steering wheel.

The CCB fits within the cockpit while confirming the possibility of having different solutions for its design. Because even though the CCB may have a structural function and thus being very important to the overall performance of the vehicle, its design is not predetermined. In fact, when thinking of designing a CCB it is important to understand that this component is intended to take the minimum space or rather merely occupy the space that is left after placing all subsystems that have to be on the front area of the cockpit, for instance: the glove box, the HVAC system, the electric wiring, and so on. This means that regarding shape itself there is no layout to follow, it will mostly depend on the type of vehicle and, the amount and type of subsystems that will constitute the cockpit.

                                                                                             Figure.2 (a) CCB location inside the car dashboard

                                                                                                      Figure.2 (B) CCB location inside the car dashboard 

Components of a CCB 

                                                                                                        Figure 3. component of CCB

1. End brackets and A-pillars
2. Steering column bracket
3. Gloves box bracket
4. Vertical braces
5. Crossbeam tube
6. Cowl top brace

PROCEDURE:

Import CAD model and geometry cleanup.

Once importing the CAD model do Topo over the entire model and do geometry check.

                                                                                       figure 4. Imported Geometry

After the check execution if all the errors are fixed go for the next step i.e Mid-surface extraction.

                                                                                                   Figure. 5 geometry check

Mid-surface generation and set different PID with Thickness value.

Before extracting mid-surface measure the thickness over the entire geometry. This will help in deciding the thickness to the new property created.

                                                                                                Figure.6 Thickness measurement of the CCB Assembly

One by one with a manual offset method we can extract mid surface and allot them different thicknesses

                                                                                       Figure. 7 Mid-surface of the CCB Assembly

All the part are segregated according to there thickness under different PID

Figure. 8 Mid-surface property ID of the CCB Assembly

Quality and Mesh parameter setup.

Setup the parameter for Quality and Mesh.

Meshing and Mesh correction.

                                                                                   Figure.9 meshed model of CCB

Deploying weld and RB connections as per requirement. 

Below the figures illustrate the deployment of weld and RB 2 connection required.

1) A-pillar and cross beam tube 

2) RB 2 cluster connection 

3) Double row weld connection

4)Double row weld connection

5) Bolts with a washer hole rigid connection

6) Bracket and beam tube connection

7) Bolt representation with the RB2 cluster.

8) Capturing washer bolt holes with zone cut 

9)RB2 cluster rigid connection 

10) Spot weld connection with RB3 Hexa element

FINAL RESULT:

CONCLUSION:

The mid surface extracted captures all the features correctly and the meshing is done over the mid surface the with required quality requirement. The mesh flow is smooth and uniform with a target length of 5mm. The connection deployed are with seam weld are done in a decent way which is acceptable and this final model can be used further for the next process i.e. in a solver.