mandrel engage secondary cutter rings to increase the effective number of teeth deforming the sacrificial tube during the stroke alternatively a parallel load path may be engaged using a secondary mechanical energy absorber during part or all of the stroke of the device simpler geometries for the mechanical energy absorber of the present invention may also provide continuous deformation and possible rupture the tube geometry may be any closed section the cutting teeth may be simplified to bosses at the cost of increased friction the cutting teeth may be direct cutters that cut through the tube without applying a significant radial force the closed section of the tube may be forced to reduce in circumference and buckle inward locally in a controlled manner the tube may be replaced by one or more strips or open sections that are forced through a deformation process that causes localized bending and or shearing within the cross section referring now to fig1 a second advantageous embodiment of the invention operates in a similar manner but with a modification to the geometry of the deforming and deformable elements the deformable element consists of axially oriented tubes 20 arrayed in the annular space between an inner deforming element or mandrel 19 and outer housing 18 each tube in the array makes a line contact with the mandrel 19 and deforms locally and continuously during the stroke of the device the mandrel 19 consists of a small diameter leading section and a larger diameter.