Methods and systems for numerically simulating inflation of an airbag configured with a plurality of connected flexible-boundary volumes

• US 8,577,656 B1
• Filed: 09/20/2011
• Issued: 11/05/2013
• Est. Priority Date: 09/20/2011
• Status: Active Grant

• Current Assignee: Ansys Incorporated
• Original Assignee: Livermore Software Technology Corporation
• Inventors: Teng, Hailong, Wang, Chi-Hsien
• Primary Examiner(s): Rivas, Omar Fernandez
• Assistant Examiner(s): KHAN, IFTEKHAR A
• Application Number:
  US13/237,607
• Time in Patent Office: 777 Days
• Field of Search: 703/7
• US Class Current: 703/7
• CPC Class Codes: G06F 30/23 using finite element methods [FEM] or finite difference methods [FDM]

Abstract

Systems and methods for numerically simulating inflation of an airbag configured with more than one connected flexible-boundary volumes (i.e., primary and secondary pouches) are disclosed. A finite element analysis model of such airbag is defined in the airbag'"'"'s folded configuration. Numerical simulation of inflating the primary pouch is based on corpuscular particle theory by interacting simulated corpuscular or gas particles with one another and with the shell elements representing the primary pouch. The simulated corpuscular particles are created by flow characteristics generated by an explosive blast. Numerical simulation of inflating the secondary pouch is based on control volume theory by converting kinetic energy of those of the simulated corpuscular particles having flowed through the interconnected opening from the primary to the secondary pouch to a uniform pressure. The uniform pressure is then applied onto the shell elements representing the secondary pouch.

Claims

1. A method of numerically simulating inflation of an airbag configured with at least primary and secondary connected pouches, the primary pouch being inflated by an explosive blast initially, while the secondary pouch being inflated by air having flowed through one or more interconnection openings between said primary and secondary pouches, said method comprising:

defining a finite element analysis (FEA) model of an airbag in an initial folded configuration, said airbag having at least primary and secondary pouches connected by one or more interconnection openings, said primary and secondary pouches being represented in the FEA model by a first plurality of shell elements and a second plurality of shell elements, respectively;

conducting a first numerical simulation of inflating the primary pouch using the FEA model according to corpuscular particle theory by interacting simulated corpuscular particles with one another and with the first plurality of shell elements, said simulated corpuscular particles being created according to an explosive blast'"'"'s strength and each of the simulated corpuscular particles being assigned with a numerical kinetic energy;

conducting, in conjunction with the first numerical simulation, a second numerical simulation of inflating the secondary pouch using the FEA model according to control volume theory by converting numerical kinetic energy of those of the simulated corpuscular particles having flowed from the primary pouch to the secondary pouch through the interconnection openings to a uniform pressure acting upon the second plurality of shell elements,

wherein said uniform pressure is calculated as follows;

2. The method of claim 1, wherein the explosive blast'"'"'s strength is defined by gas mass flow rate, temperature, and total number of the simulated corpuscular particles to be used in the first numerical simulation.

3. The method of claim 2, wherein each of the simulated corpuscular particles is assigned with an arbitrarily random direction injected into the primary pouch.

4. The method of claim 3, wherein the corpuscular particle theory includes tracking the simulated corpuscular particles for collisions with one another and with the first plurality of shell elements.

5. The method of claim 4, wherein said collisions including transferring the numerical kinetic energy between two of the simulated corpuscular particles or between one of the simulated corpuscular particles and one of the first plurality of shell elements.

6. The method of claim 1, wherein the uniform pressure further includes a contribution from ambient air pressure when the secondary pouch is configured with one or more outside openings allowing ambient air to flow in during said inflating the secondary pouch.

7. A non-transitory computer readable storage medium containing computer executable instructions for numerically simulating inflation of an airbag configured with at least primary and secondary connected pouches, the primary pouch being inflated by an explosive blast initially, while the secondary pouch being inflated by air having flowed through one or more interconnection openings between said primary and secondary pouches by a method comprising:

defining a finite element analysis (FEA) model of an airbag in an initial folded configuration, said airbag having at least primary and secondary pouches connected by one or more interconnection openings, said primary and secondary pouches being represented in the FEA model by a first plurality of shell elements and a second plurality of shell elements, respectively;

conducting a first numerical simulation of inflating the primary pouch using the FEA model according to corpuscular particle theory by interacting simulated corpuscular particles with one another and with the first plurality of shell elements, said simulated corpuscular particles being created according to an explosive blast'"'"'s strength and each of the simulated corpuscular particles being assigned with a numerical kinetic energy;

conducting, in conjunction with the first numerical simulation, a second numerical simulation of inflating the secondary pouch using the FEA model according to control volume theory by converting numerical kinetic energy of those of the simulated corpuscular particles having flowed from the primary pouch to the secondary pouch through the interconnection openings to a uniform pressure acting upon the second plurality of shell elements,

wherein said uniform pressure is calculated as follows;

8. The non-transitory computer readable storage medium of claim 7, wherein the explosive blast'"'"'s strength is defined by gas mass flow rate, temperature, and total number of the simulated corpuscular particles to be used in the first numerical simulation.

9. The non-transitory computer readable storage medium of claim 8, wherein each of the simulated corpuscular particles is assigned with an arbitrarily random direction injected into the primary pouch.

10. The non-transitory computer readable storage medium of claim 9, wherein the corpuscular particle theory includes tracking the simulated corpuscular particles for collisions with one another and with the first plurality of shell elements.

11. The non-transitory computer readable storage medium of claim 10, wherein said collisions including transferring the numerical kinetic energy between two of the simulated corpuscular particles or between one of the simulated corpuscular particles and one of the first plurality of shell elements.

12. The non-transitory computer readable storage medium of claim 7, wherein the uniform pressure further includes a contribution from ambient air pressure when the secondary pouch is configured with one or more outside openings allowing ambient air to flow in during said inflating the secondary pouch.

13. A system for numerically simulating inflation of an airbag configured with at least primary and second connected pouches, the primary pouch being inflated by an explosive blast initially, while the secondary pouch being inflated by air having flowed through one or more interconnection openings between said primary and secondary pouches, the system comprising:

an input/output (I/O) interface;

a memory for storing computer readable code for one or more application modules configured for airbag deployment simulation;

at least one processor coupled to the memory, said at least one processor executing the computer readable code in the memory to cause said one or more application modules to perform operations of;

defining a finite element analysis (FEA) model of an airbag in an initial folded configuration, said airbag having at least primary and secondary pouches connected by one or more interconnection openings, said primary and secondary pouches being represented in the FEA model by a first plurality of shell elements and a second plurality of shell elements, respectively;

conducting a first numerical simulation of inflating the primary pouch using the FEA model according to corpuscular particle theory by interacting simulated corpuscular particles with one another and with the first plurality of shell elements, said simulated corpuscular particles being created according to an explosive blast'"'"'s strength and each of the simulated corpuscular particles being assigned with a numerical kinetic energy;

conducting, in conjunction with the first numerical simulation, a second numerical simulation of inflating the secondary pouch using the FEA model according to control volume theory by converting numerical kinetic energy of those of the simulated corpuscular particles having flowed from the primary pouch to the secondary pouch through the interconnection openings to a uniform pressure acting upon the second plurality of shell elements, wherein said uniform pressure is calculated as follows;

14. The system of claim 13, wherein the explosive blast'"'"'s strength is defined by gas mass flow rate, temperature, and total number of the simulated corpuscular particles to be used in the first numerical simulation.

15. The system of claim 14, wherein each of the simulated corpuscular particles is assigned with an arbitrarily random direction injected into the primary pouch.

16. The system of claim 15, wherein the corpuscular particle theory includes tracking the simulated corpuscular particles for collisions with one another and with the first plurality of shell elements.

17. The system of claim 13, wherein the uniform pressure further includes a contribution from ambient air pressure when the secondary pouch is configured with one or more outside openings allowing ambient air to flow in during said inflating the secondary pouch.