TECHNOLOGICAL FIELD

The present disclosure relates generally to the design and the manufacture of a liquid container onboard a vehicle and, in particular, to certifying the design of a liquid container for manufacture based on a slosh prediction.

BACKGROUND

The sloshing of liquid inside a liquid container onboard a vehicle such as an aircraft induces stress and fatigue on the container as well as its integrated components, such as screws, bolts, caps, hoses, sealants, pylons, struts, fairings, nozzles and the like. Due to the effects of vehicle dynamics on sloshing, this stress and fatigue can be especially heightened during more extreme vehicle maneuvers. Stress and fatigue can lead to cracking, crumbling, or other types of part failure, which can lead to loss of functionality of components, loss of functionality of the liquid container, introduction of foreign object debris, leakage, introduce electrical/magnetic vulnerabilities, and more.

In order to mitigate these risks of part failure inside the liquid container, analysis teams use experimentation tools to understand and predict the risks. The teams may use this information to optimize the design of the liquid container and its integrated components and to certify that requirements for reliability and risk tolerance are met.

The design and certification of a liquid container and its components can be expensive and laborious. Current certification processes do not provide sufficient feedback to designers of the liquid container and components to understand the physical conditions and risks that the liquid container and components will be subjected to and to sufficiently improve the design and implementation accordingly. Shortcomings of the current processes include the absence of genuine vehicle dynamics, as well as qualitative rather than quantitative analysis results. Current processes also do not provide sufficient feedback for understanding the physical conditions and risks on a vehicular liquid container and its components. In many cases current processes only provide analysis results that are course, qualitative, and time-averaged rather than fine (continuous), quantitative, and temporal. Additionally, none of these processes have integrated the experimentation into a database of vehicle data that allows for testing and certification under the direct selection of the most extreme vehicle maneuvers of interest.

Therefore it would be desirable to have a system and method that takes into account at least some of the issues discussed above, as well as other possible issues.

BRIEF SUMMARY

Example implementations of the present disclosure are generally directed to a system, and corresponding method and computer-readable storage medium for certifying a design of a liquid container. Example implementations provide computational models that develop a virtual test bed process for exploring the action of liquid slosh on a container cap design and other internal components within a liquid container such as a fuel tank onboard an aircraft. The system includes an option of using recorded flight data to incorporate real flight maneuver dynamics into the simulation. Utilization of the system has the potential to significantly reduce the costs associated with fuel tank and fuel-tank-component testing as well as deliver certification of parts and liquid container based on the quantification of slosh impact and risk as opposed to just qualitative slosh predictions in the place of qualitative binary results. It greatly improves accuracy and the level of certification detail, and doing so while directly processing recorded flight data to incorporate real flight dynamics to account for the effects of the most extreme flight maneuvers. Additionally, the system provides a framework for integrating sub-processes and provides predictive feedback.

Example implementations are primarily described in the context of fuel tanks onboard aircraft, but other liquid containers onboard aircraft and other vehicles are also contemplated. Aircraft fuel tanks in general contain multiple intricate components requiring certification under their full range of flight maneuvers. Spacecraft can have very complicated liquid cryogenic systems and microgravity formation of liquids during launch and reentry that can be characterized by very complicated wave motion. Ships and submarines can have water ballast tanks in which complicated wave motion may cause problems for internal component design within these tanks. More generally, this includes any tank or container used for liquid storage, including: integrated tanks, rigid and/or removable tanks, bladder tanks, tip tanks, conformal tanks, drop and/or pylon tanks, ballast tanks including saddle ballasts, cryogenic liquid tanks, septic tanks, and/or cooling tanks or reservoirs. A sample list of components and parts of applicability include: fuel pump, fuel filter, fuel injector, seal caps, sensors, hoses, valves, clamps, plugs, screws, bolts, sealants, struts, pylons, baffles, and other components of the fuel tanks, as well as additional components of other vehicle liquid tanks and containers. The certification of the design of these internal components is a significant problem that spans these many different vehicle environments, systems, and components, all of which would fit into the proposed framework of example implementations of the present disclosure.

Example implementations disclosed herein provide certification teams with accurate, quantified, high-fidelity predictions of the stress and “locations of fatigue-risk” on tanks and components within the tanks. These high-fidelity predictions are not available via current experimental testing. Providing stress and fatigue-risk locations on the tanks and components within the tanks while the tank/components are being subjected to extreme vehicle maneuvers selected from an integrated database of vehicle dynamics data, are also not possible in the current experimental setup. Additionally, this approach reduces the associated experimentation costs through efficient framework integration of all certification sub-processes.

The present disclosure thus includes, without limitation, the following example implementations.

Some example implementations provide a method for certifying a design of a liquid container onboard a vehicle, the method comprising generating a computer geometric model of the liquid container according to the design of the liquid container; generating executable code to reproduce dynamics and operational parameters of the vehicle, the dynamics of the vehicle including dynamics during a vehicle maneuver that is selectable from a database of vehicle dynamics for a plurality of vehicle maneuvers; executing a simulating application, via a computer processor configured to access the computer geometric model and the executable code, to at least: perform a simulation of liquid sloshing in the liquid container onboard the vehicle subject to the dynamics and operational parameters, including the dynamics during a selected one or more of the plurality of vehicle maneuvers, and produce a prediction of loads and stresses on the liquid container from the simulation, the prediction having an associated prediction error; and iterate the simulation to reduce the associated prediction error and thereby refine the prediction of loads and stresses on the liquid container; identifying respective locations within the liquid container that are more vulnerable to fatigue-risk based on the prediction of loads and stresses on the liquid container; and outputting the respective locations and the prediction of stresses on the liquid container at least at the respective locations, including in at least one instance, an indication of certification of the design of the liquid container based thereon.

In some example implementations of the method of any preceding or any subsequent example implementation, or any combination thereof, the liquid container includes a plurality of components integrated or assembled thereon, and generating the computer geometric model of the liquid container includes generating a first computer geometric model of the liquid container without the plurality of components; generating a plurality of second computer geometric models of the plurality of components; and integrating the first computer geometric model and the plurality of second computer geometric models to generate the computer geometric model of the liquid container.

In some example implementations of the method of any preceding or any subsequent example implementation, or any combination thereof, generating the executable code to reproduce dynamics and operational parameters of the vehicle includes receiving selected dynamics from the database of vehicle dynamics for the plurality of vehicle maneuvers including two or more of takeoff, launch, ascent, roll, bank, descent, laminar or turbulent cruise, evasive maneuvers, right/left turn, U-turn, lane change, launch from stop, brake, or curve-handling.

In some example implementations of the method of any preceding or any subsequent example implementation, or any combination thereof, generating the executable code to reproduce dynamics and operational parameters of the vehicle includes receiving operational parameters from a database of a plurality of operational parameters of the vehicle, including two or more of a temperature of the liquid container onboard the vehicle, a type of liquid in the liquid container, ambient gas in the liquid container, or initial fill level of liquid in the liquid container.

In some example implementations of the method of any preceding or any subsequent example implementation, or any combination thereof, executing the simulating application to perform the simulation includes executing the simulating application to perform the simulation to produce the prediction of loads and stresses including a pressure and a velocity flow field induced throughout an interior of the liquid container, and wherein identifying respective locations within the container that are more vulnerable to fatigue-risk includes determining a location of a fluid interphase boundary surface based on the pressure and the velocity flow field.

In some example implementations of the method of any preceding or any subsequent example implementation, or any combination thereof, outputting the respective locations and the prediction of stresses includes, in at least one other instance, producing a modified design of the liquid container based on the respective locations within the liquid container that are more vulnerable to fatigue-risk, and the prediction of stresses on the liquid container at least at the respective locations; generating a modified computer geometric model of the liquid container according to the modified design; and re-executing the simulating application via the computer processor configured to access the modified computer geometric model and the executable code.

In some example implementations of the method of any preceding or any subsequent example implementation, or any combination thereof, outputting the design for production of the liquid container according thereto.

Some example implementations provide an apparatus for certifying a design of a liquid container onboard a vehicle for manufacture of the liquid container. The apparatus comprises a processor and a memory storing executable instructions that, in response to execution by the processor, cause the apparatus to at least perform the method of any preceding example implementation, or any combination thereof. This may include implementation of a liquid container certification system including a modeling subsystem, parameters and dynamics subsystem and simulation subsystem coupled to one another and configured to perform steps of the method.

Some example implementations provide a computer-readable storage medium that is non-transitory and has computer-readable program code portions stored therein that in response to execution by a processor, cause an apparatus to at least perform the method of any preceding example implementation, or any combination thereof.

These and other features, aspects, and advantages of the present disclosure will be apparent from a reading of the following detailed description together with the accompanying drawings, which are briefly described below. The present disclosure includes any combination of two, three, four or more features or elements set forth in this disclosure, regardless of whether such features or elements are expressly combined or otherwise recited in a specific example implementation described herein. This disclosure is intended to be read holistically such that any separable features or elements of the disclosure, in any of its aspects and example implementations, should be viewed as combinable, unless the context of the disclosure clearly dictates otherwise.

It will therefore be appreciated that this Brief Summary is provided merely for purposes of summarizing some example implementations so as to provide a basic understanding of some aspects of the disclosure. Accordingly, it will be appreciated that the above described example implementations are merely examples and should not be construed to narrow the scope or spirit of the disclosure in any way. Other example implementations, aspects and advantages will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of some described example implementations.

