Mesh
Seed edges
Firstly, select Part in upper right panel and choose 'frame'. Click Seed Edges (button with shaded background in the figure) and select all the edges.
In the new window, we set the Number of elements as 10, which means each edge has 10 seeds.
Then, convert the perspective by clicking at z-axis.
And click Turn Perspective Off.
Because the slice is thin enough, we change the seeds on these edges along y-axis to 1.
Mesh
Next step, click Assign Element Type button.
Enable Incompatible modes option, with other options set as default. Thus, the mesh type is C3D8I, as shown below.
Then click Mesh Part Instance and get the meshed frame as shown below.
The mesh of airbag can be implemented in a similar way. The result is illustrated like this.