The present invention is related to a nested crash box used as a passive safety component in vehicles, the content of which is obtained by connecting nested tubes of various lengths through the use of metal connecting techniques such as welding and hot forming for metal materials, and different adhesion techniques for composite materials. The present invention comprises a nested tube design which reduces the frontal acceleration of the passenger and stores the energy in a shorter crushing distance thanks to its stepped structure.

Known State of the Art ( Prior Art)

Nowadays, the crushing and collapsing rates of vehicles (planes, automobiles, ships, etc.) in any accident are of significant importance. Active and passive safety hardware related to vehicle safety are precautions for reducing accidents. Active safety hardware are used for elim inating or reducing the accident occurrence whereas passive safety hardware are designed to minimize the damage suffered by the vehicle occupants and the other parties in the accidents which happen despite all the measures that are taken . One of these hardware, each one vital for safety of life, is the crash box. During impacts, the crash energy is absorbed by the body of the automobile, thereby providing in-cabin safety.

Their designs have been improved in order to increase the protective qualities and performances of vehicles. I n order to shorten the design periods and to achieve the safe design standards in terms of crash resistance and components, virtual tests are usually performed with digital sim ulations. Virtual crush and crash test data are used throughout the development of a new product's design . First, the prototype of the vehicle is built.

The mechanical properties of the materials can be determined via various tests. Tension , compression , flexure, torsion , fatigue, creeping, rigidity and impact tests are among such tests. These tests can offer insight about the mechanical behavior of the materials. I n case of a crush or crash , the most important event is the absorption of kinetic energy. Crash boxes are designed for this end and are being used in many cases. Under severe conditions, they can absorb a significant portion of the occurring kinetic energy, thereby converting it into plastic strain energy. Therefore, axial breaking, crashing and collapsing behaviors are of vital importance. I n any case of accident, the aim is to have an absorption of the kinetic energy stored in the vehicle with a balanced oscillation. This is achieved thanks to the impact absorbing crash boxes with different forms and geometries. Thanks to the impact absorbers of the vehicle, kinetic energy is converted into energy of strain through plastic deformation. Stable straining of the impact absorbers allow the kinetic energy to be better converted into energy of strain. Thus, the inertia effect of the vehicle is reduced.

The patent document no: CN102745158 (A) in the known art relates to an energy absorbing crash box comprising a crash box and another crash box covering the former by enclosing it, for the purpose of achieving maximum reduction in the crash effect thanks to the energy absorbing boxes opening during an automobile accident. The automobile crash box has an A-shape, contains an energy absorbing box body; energy absorbing case comprises a box cover and connection element connected to each other in order to form a box body and a void structure. I n said invention, the goal is to separate the single crashing event into two branches via the A-shaped structure and to disperse the impact wave across the material in the wide cross section. A nested, equiaxed or non-equiaxed system is not present in the known art.

Considering the present applications in the known art, it should be appreciated that there isn't any design such as the nested, equiaxed crash box of the present invention, made of any material with different lengths and wall thicknesses.

Brief Description and Objective of the I nvention

The nested crash box of the present invention utilized as a passive safety component in vehicles, is made of multiple nested tubes of any shape and it is designed to be used in connection with front or rear fuselage and rear or front bumper.

The objective of the invention is to store more kinetic energy as plastic energy and to reduce the damage suffered by the occupant by reducing the crash impact. Another objective of the invention is to reduce the system length, increase the crush force efficiency and reduce the system weight by placing tubes of various lengths concentrically or non-concentrically.

Description of the Figures [Explaining the I nvention

The figures prepared for a better description of the nested crash box of the present invention as a passive safety component in vehicles, are provided below.

Figure 1 : top view of the nested triple square - square - square crash box

Figure 2: top view of the nested triple circle - square - square crash box Figure 3: top view of the nested triple square - circle - square crash box

Figure 4: top view of the nested triple circle - circle - circle crash box

Figure 5: side view of the nested triple crash box of various lengths

Figure 6: side view of the nested triple crash box of an outside-to-inside decreasing length

Figure 7: side view of the nested double crash box of an outside-to-inside decreasing length

Figure 8: side view of the nested double crash box of an inside-to-outside decreasing length

Figure 9: the nested triple circle - circle - circle crash box

Detailed Description of the I nvention

The present invention is related to a nested crash box used as a passive safety component in vehicles, the content of which is obtained by connecting nested tubes of various lengths through the use of metal connecting techniques such as welding and hot forming for metal materials, and different adhesion techniques for composite materials. The present invention comprises a nested tube design which reduces the frontal acceleration of the passenger and stores the energy in a shorter crushing distance thanks to its stepped structure.

The nested crash box, which is used a passive safety component in vehicles with various geometries, formed by connecting tubes of various lengths using various connection methods, is designed to be used in connection with front or rear fuselage and rear or front bumper.

The most important feature of the invention is that nested crash box components of various lengths are recommended. Thus, when the tubes are of different lengths, the component that meets the impact first can slow it down and transfer the impact to the other components. The boxes are not communication with each other. There should be at least 1 mm gap between the outer portion of the inner box and the inner potion of the outer box. The wall thickness of the boxes may be at least 0.1 mm and at most 10 mm.

As the accident occurs, the design, material type, sectional geometry or collapsing rate of the crash box in the vehicle cause the reaction force to be varied.

I n one embodiment of the present invention, there are at least 2 tubes. The tubes can be of a same or a different geometry.

Thanks to the present invention, more kinetic energy is stored as plastic energy and the damage suffered by the occupant is reduced by reducing the crash impact. The invention also reduces the system length, increases the crush force efficiency and reduces the system weight by placing tubes of various lengths concentrically or non- concentrically.