Aircraft Fuselage Strut Failure-Initiating Element for Crash Energy Absorption
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Solution Overview
Problem
Current aircraft fuselage structures, especially those made of composite materials, struggle to effectively absorb impact energy during crashes, leading to premature deformation and reduced energy absorption capacity, which increases the risk to passengers and necessitates heavier structures to withstand forces.
Innovation Solution
Incorporating a failure-initiating element that applies a lateral force to the struts during impact, delaying their buckling and reducing the force transmission to upper structural elements, thereby maximizing energy absorption by the lower portion of the fuselage while minimizing the overall mass of the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the struts are designed with high structural resistance to withstand crash forces, then the safety and reliability are improved, but the mass of the structure increases and energy absorption capacity is reduced
Solution Approach 1:
The failure-initiating element is pre-installed on the strut at a specific location before the crash occurs. This preliminary placement ensures that during impact, the element will apply the spurious force at the optimal moment and location to induce early buckling, preventing the strut from transmitting full crash forces to upper structures while avoiding the need for excessive mass
Solution Approach 2:
The failure-initiating element acts as an intermediary component between the strut and the upper floor structure. It mediates the force transmission by applying a lateral spurious force that triggers controlled early buckling of the strut, thereby limiting the force transmitted to passengers while maintaining overall structural safety
2Loss of energy
If the lower floor structure is designed to absorb maximum impact energy through crushing, then the energy absorption capacity is improved, but the force transmitted to the upper structure increases causing premature deformation
Solution Approach 1:
The failure-initiating element serves as an intermediary that controls the interaction between the lower floor structure and upper structure during impact. By applying a lateral force to the strut, it ensures that energy absorption occurs in the lower portion while preventing excessive force transmission that would cause premature deformation of the upper structure
Solution Approach 2:
The invention changes the force transmission parameters by introducing a lateral spurious force component through the failure-initiating element. This modifies the stress state in the strut during impact, promoting buckling at a controlled location and time, thereby optimizing the balance between energy absorption and force transmission to upper structures
3Weight of moving object
If the struts are made lighter to reduce overall aircraft mass, then the weight is reduced, but the structural resistance decreases leading to premature deformation during crash
Solution Approach 1:
By pre-installing the failure-initiating element on the lighter strut, the system ensures that the strut will buckle at the optimal moment during impact. This preliminary preparation allows the lighter strut to provide sufficient structural resistance for normal operations while ensuring controlled failure behavior during crash to maintain safety
Solution Approach 2:
The invention converts the potential harm of using lighter, weaker struts into a benefit by designing the failure-initiating element to trigger controlled early buckling. This ensures that when the lighter strut does fail during crash, it does so in a predictable manner that limits force transmission to passengers, thereby maintaining safety despite reduced mass
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for efficient energy absorption during crashes, reducing the structural resistance and mass of the upper portion of the fuselage, while maintaining structural integrity and minimizing the need for overdimensioning, thus enhancing passenger safety and reducing aircraft weight.
Implementation Method 1
said failure-initiating element applies to said strut a spurious force under the influence of an impact force oriented substantially in the radial direction and inward relative to a longitudinal axis of the primary fuselage structure so as to favor early failure in buckling of the strut
Data Source
AI summary
A primary fuselage structure for an aircraft, including circumferential frames, a floor structure having lateral ends connected to the circumferential frames, at least one strut supporting the floor structure and including a lower end fixed on a circumferential frame and an upper end fixed on the floor structure, and at least one failure-initiating element associated with the strut, including a first arrangement for fastening the strut to a circumferential frame, at a distance from the lower end of the strut, as well as a second arrangement for attaching the circumferential frame to the strut, away from the ends of the strut. A fuselage segment and aircraft, such as an airplane, including the primary fuselage structure are also provided.