Search

EP-4735236-A1 - METHOD FOR ASSEMBLING BIAXIALLY ORIENTED POLYETHYLENE TEREPHTHALATE STRIPS

EP4735236A1EP 4735236 A1EP4735236 A1EP 4735236A1EP-4735236-A1

Abstract

A method for assembling a first biaxially oriented polyethylene terephthalate strip and a second biaxially oriented polyethylene terephthalate strip for manufacturing an inflatable structure of a deployable kit for space debris capture, the method comprising the steps of: a) arranging a stack of the first strip and the second strip on a bearing face of an anvil, b) applying a sonotrode to compress said stack between a welding face of the sonotrode and the bearing face of the anvil, c) welding the two strips by the emission of ultrasound by the sonotrode through the stack.

Inventors

  • HRAZMI, Issam
  • BEURET, Killian
  • BRODARD, Laurent
  • Mbiakop Ngassa, Armel

Assignees

  • COMPAGNIE GENERALE DES ETABLISSEMENTS MICHELIN

Dates

Publication Date
20260506
Application Date
20240628

Claims (10)

  1. 1. A method of manufacturing an inflatable structure (1) of a deployable kit (100) for capturing space debris comprising the steps of: i) assembling a first strip (12) of biaxially oriented polyethylene terephthalate and a second strip (14) of biaxially oriented polyethylene terephthalate so as to form an assembly (7) of biaxially oriented polyethylene terephthalate by implementing the following steps: - arrangement of a stack of the first strip (12) and the second strip (14) on a support face (31) of an anvil (3), - application of a sonotrode (4) to compress said stack between a welding face (41) of the sonotrode (4) and the support face (31) of the anvil (3), - welding the first and second strips (12, 14) by emitting ultrasound through the stack by the sonotrode (14), ii) winding the assembly (7) produced in step i) so as to cover a first edge (71) of the assembly (7) with a second edge (72) of the assembly (7) so as to form a tube, iii) assembling the first edge (71) and the second edge (72) by implementing the following steps: - arrangement of a stack of the first edge (71) and the second edge (72) on the support face (31) of the anvil (3), - application of the sonotrode (4) to compress said stack between the welding face (41) of the sonotrode (4) and the support face (31) of the anvil (3), - welding of the first and second edges (71, 72) by emission of ultrasound through the stack by the sonotrode (14).
  2. 2. A method according to claim 1, wherein the weld made in step i) is a shear weld and the weld made in step iii) is a peel or shear weld.
  3. 3. Method according to any one of claims 1 and 2, in which the welding steps are carried out by carrying out a relative movement between the sonotrode (4) and the stack.
  4. 4. Method according to any one of claims 1 to 3, in which, during the welding step in step i), the first strip (12) and the second strip (14) are deformed simultaneously with the welding so as to create a mechanical anchoring of the first strip (12) in the second strip (14) and/or, during the welding step in step iii ...iv), the second strip (14) is deformed simultaneously with the welding so as to create a mechanical anchoring of the first strip (12) in the second strip (14) and/or, during the welding step in the first edge (71) and the second edge (72) simultaneously with welding so as to create a mechanical anchoring of the first edge (71) in the second edge (72).
  5. 5. A method according to any one of claims 1 to A, wherein the welding in step i) is carried out substantially without mechanical deformation of the first strip (12) and the second strip (14) and/or the welding in step iii) is carried out substantially without mechanical deformation of the first edge (71) and the second edge (72).
  6. 6. Method according to claim 5, comprising a step prior to the welding step of step i) of arranging a filler material (8) between the first strip (12) and the second strip (14), said filler material (8) melting at least partially during welding and/or comprising a step prior to the welding step of step iii) of arranging a filler material (8) between the first edge (71) and the second edge (72), said filler material (8) melting at least partially during welding.
  7. 7. Method according to claim 6, in which the filler material (8) is linear polyester, preferably polyethylene terephthalate and even more preferably biaxially oriented polyethylene terephthalate.
  8. 8. Method according to any one of claims 1 to 7, in which the ultrasounds are emitted at a frequency between 25 kHz and 40 kHz.
  9. 9. Inflatable structure (1) of a deployable kit (100) for capturing space debris comprising a first strip (12) of biaxially oriented polyethylene terephthalate and a second strip (14) of biaxially oriented polyethylene terephthalate assembled by welding, characterized in that the inflatable structure (1) is capable of being inflated up to 2 x 10 6 Pa (20 bars).
  10. 10. Inflatable structure (1) according to claim 9, characterized in that said welding is carried out by emitting ultrasound through a stack of said strips (12, 14).

Description

DESCRIPTION TITLE: Method for assembling biaxially oriented polyethylene terephthalate strips FIELD OF THE INVENTION The present invention relates to the field of deorbiting space debris, more precisely to such deorbiting from a deployable kit comprising an inflatable structure and a net, and, more particularly still, to a method of assembling Mylar™ strips for the manufacture of such an inflatable structure. STATE OF THE ART The INSIDeR (Innovative Net & Space Inflatable structure for active Debris Removal) system aims to safely deorbit space debris of different sizes. This system is a kit comprising a flexible net with high mechanical resistance serving as a capture system capable of capturing large objects and adapting to different debris morphologies and their tumbling speed and a tubular inflatable structure supporting said net serving as a net deployment system and ensuring the control and damping of debris movement. The inflatable structure comprises an assembly of sections, notably tubular, composed of sheets of biaxially oriented polyethylene terephthalate (BOPET) also commonly called Mylar™. Inflatable Mylar™ structures intended to be sent into space are known from the prior art and are assembled by gluing. However, gluing does not allow for a long-term resistant assembly and there is thus a risk of delamination. PRESENTATION OF THE INVENTION An aim of the invention is to enable the assembly of sections of an inflatable structure of a deployable kit for capturing space debris which makes it possible to obtain an inflatable structure which is resistant over the long term for use in space, preferably at least ten years, more preferably at least twenty years. An aim of the invention is therefore to enable the production of an inflatable structure which has good mechanical strength at very high inflation pressures, preferably at around 2 x 10 6 Pa (20 bar). Another aim of the invention is to enable the production of an inflatable structure which is watertight and continuous, that is to say made of a single material. According to a first aspect, there is provided a method of assembling a first strip of biaxially oriented polyethylene terephthalate and a second strip of biaxially oriented polyethylene terephthalate for the manufacture of an inflatable structure of a deployable kit for capturing space debris, the method comprising the steps of: a) arranging a stack of the first strip and the second strip on a bearing face of an anvil, b) applying a sonotrode to compress said stack between a welding face of the sonotrode and the bearing face of the anvil, c) welding the first and second strips by emitting ultrasound through the stack by the sonotrode. According to advantageous and non-limiting characteristics, taken alone or in combination when technically possible: - welding is carried out by performing a relative movement between the sonotrode and the stack; - the first strip and the second strip are deformed simultaneously during welding so as to create a mechanical anchoring of the first strip in the second strip; - welding is carried out substantially without mechanical deformation of the first strip and the second strip; - the method comprises a step a1) prior to step b) of arranging a filler material between the first strip and the second strip, said filler material melting at least partially during welding; - the filler material is linear polyester, preferably polyethylene terephthalate and even more preferably biaxially oriented polyethylene terephthalate; - the first strip and the second strip are parts of different biaxially oriented polyethylene terephthalate sheets; - the first strip and the second strip are parts of the same sheet of biaxially oriented polyethylene terephthalate; - ultrasound is emitted at a frequency between 25 kHz and 40 kHz. According to a second aspect, a method for manufacturing an inflatable structure of a deployable kit for capturing space debris is provided, comprising the steps of: i) assembling a first strip of biaxially oriented polyethylene terephthalate and a second strip of biaxially oriented polyethylene terephthalate by implementing the method as described above so as to form an assembly of biaxially oriented polyethylene terephthalate, ii) winding the assembly produced in step i) so as to cover a first edge of the assembly with a second edge of the assembly so as to form a tube, iii) assembling the first edge and the second edge by implementing the method as described above. Advantageously, the weld made in step i) is a shear weld and the weld made in step iii) is a peel or shear weld. According to a third aspect, there is provided a system for implementing the method as described above, comprising: - an ultrasonic generator, - a sonotrode adapted to emit the ultrasounds generated by the generator from a welding face, - an anvil having a support face arranged opposite the welding face of the sonotrode. According to advantageous and non-limiting characteris