High-reliability large-current grounding system and design method thereof

Abstract

The invention belongs to the technical field of aviation electrical, and discloses a high-reliability large-current grounding system and a design method thereof, and the system comprises a backbone network which is used for laying a conductive medium along a main force-bearing structure of an aircraft to form a low-impedance main discharge channel; in the regional network, a local low-impedance grounding looped network is constructed around backbone network nodes in an aircraft equipment concentration region; a device local network, a single device or device group being connected nearby to a device-specific ground terminal of the regional network. According to the invention, the problems that the overlap resistance is increased and the heating is serious at the grounding installation part are solved, and the robustness, long-term environmental adaptability and maintainability of the grounding system under the impact of large current can be obviously improved.

Description

Technical Field

[0001] This invention belongs to the field of grounding design technology for aviation electrical circuit interconnection systems, specifically relating to a high-reliability high-current grounding system and its design method. Background Technology

[0002] High-reliability high-current grounding systems are a core component of the safety system of aircraft electrical systems and an indispensable part of electrical circuit interconnection systems. They are mainly used to ensure the safe release and reliable grounding of current in aircraft under conditions such as high current or instantaneous discharge of high-power equipment.

[0003] With the advent of more electric and all-electric aircraft, current grounding installations for high-current grounding systems generally consist of grounding screws or bolts, ordinary washers, grounding terminals, grounding structures, and nuts. The conductive path primarily involves the contact between the grounding terminals and the grounding structure. Due to aircraft vibration and environmental corrosion, the grounding resistance gradually increases with aircraft use. When a large instantaneous ground discharge current occurs, poor grounding is prone to occur, leading to severe overheating at the grounding point and even burning out the aircraft's grounding installation structure, causing aircraft system malfunctions.

[0004] This invention proposes a design method for a high-reliability, high-current grounding system in the aviation field. This grounding design method can effectively solve the problems of increased lap resistance and severe overheating that easily occur at the grounding installation point, thereby improving the safety level of aircraft. Summary of the Invention

[0005] Purpose of the invention: To address the shortcomings of existing high-current grounding technologies in the current aviation field, this invention provides a highly reliable high-current grounding system and its design method. Through high-current grounding simulation analysis, systematic topology optimization, material innovation, connection process enhancement, and state-aware design, the robustness, long-term environmental adaptability, and maintainability of the grounding system under high-current impact can be significantly improved.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a high-reliability high-current grounding system, comprising: The main network, with conductive medium laid along the main load-bearing structure of the aircraft, forms a low-impedance main discharge channel; Regional networks are constructed around the backbone network nodes in areas where aircraft equipment is concentrated, creating local low-impedance grounding ring networks. Device local network, where a single device or group of devices is connected to the device's dedicated grounding terminal in the local area network.

[0007] As a further technical solution of the present invention: the main grid grounding is arranged on the symmetrical plane of the aircraft, and ensures good multi-point overlap with the metal skin of the aircraft.

[0008] As a further technical solution of the present invention: the conductive medium is a continuous copper alloy strip with high conductivity and high strength or a silver-plated copper braided strip; Ring networks use thinner but more flexible conductors and are connected to the main network in a star or grid pattern. The grounding terminal uses a grounding stake or grounding bar, and its location is an equipotential bonding point.

[0009] As a further technical solution of the present invention: in the critical equipment grounding connection points and areas susceptible to high current impact in the local network of the equipment, gradient composite material is used as the material of the grounding end lap surface. The gradient composite material consists of a conductive layer, a transition layer, and a structural layer, all of which are integrally molded.

[0010] As a further technical solution of the present invention: the surface of the material at the grounding connection is treated, and a connection process is adopted to achieve zero fretting corrosion and constant low contact resistance at the connection point; The surface treatment refers to applying a multi-layer composite coating to the connection interface; The connection process includes: Solid-state welding is used for critical permanent joints, employing cold metal transfer welding or friction welding to form a metallurgical bond. Use high-reliability bolt connections. For connection points requiring maintenance, use anti-loosening self-locking nuts / bolts, along with spring washers and external toothed locking washers, to apply precise and controllable torque and maintain constant clamping force. Apply conductive, antioxidant, and anti-fretting corrosion grease to the bolt threads and contact surfaces. Use dedicated spring / strap contact finger connectors for parts that require frequent plugging and unplugging or where there is relative movement. Use spring or strap contact finger grounding connectors with multi-point elastic contact.

[0011] As a further technical solution of the present invention: temperature sensors and micro-resistance measurement modules are embedded in key nodes of the backbone network, busbars of regional networks, and grounding terminals of important equipment; micro accelerometers are deployed near key connection points in vibration-prone areas to monitor vibration intensity.

[0012] As a further technical solution of the present invention: a miniaturized, low-power sensor network is integrated into the grounding system to realize real-time online monitoring of key parameters of the grounding system and real-time assessment of the health status of the grounding point.

[0013] Secondly, the present invention provides a design method for a high-reliability high-current grounding system, characterized by comprising the following steps: Arrange the main grounding channel according to the equipment grounding requirements, equipment location, and machine structure; Based on the concentrated equipment area, grounding area channels are arranged around the main channel nodes; Based on the equipment's grounding requirements, a dedicated grounding terminal is installed for the equipment and connected to the grounding area channel as close as possible.

[0014] As a further technical solution of the present invention: Establish a digital model of the grounding system that includes detailed geometry, material properties, and interface characteristics; Apply typical severe high-current surge waveforms or short-circuit current waveforms; Output grounding system parameters including temperature rise, electrodynamic force, and thermal stress. The grounding system should be optimized based on the above parameters.

[0015] As a further technical solution of the present invention: current density distribution parameters are used to identify current accumulation hotspots; By analyzing Joule heating and transient temperature rise, we can predict whether the maximum temperature exceeds the material's limit. The electromagnetic force effect is used to assess whether the electrodynamic force generated by a large current causes conductor deformation or mechanical damage to the connection point. Thermal stress can be used to analyze the thermal stress caused by rapid temperature rise and its impact on structural integrity.

[0016] In summary, the beneficial effects of the present invention are as follows: 1. The invention has extremely high high current grounding withstand capability: effectively discharges transient high currents of up to hundreds or even thousands of amperes, maximizing the protection of personnel and equipment safety.

[0017] 2. The invention features an ultra-long lifespan and ultra-high reliability of a high-current grounding system: In harsh aviation environments, it enhances the grounding system's resistance to vibration, corrosion, and temperature shock, maintains stable performance, and significantly reduces system failures caused by grounding failures.

[0018] 3. Excellent lightweight performance of the present invention: Through topology optimization and gradient material application, weight is minimized while meeting performance requirements.

[0019] 4. The intelligent health management of this invention enables the status of high-current grounding systems to be known and predicted, improving maintenance efficiency and reducing the total life cycle cost.

[0020] 5. The design process of this invention is scientific and meticulous: the design method based on multi-physics simulation greatly improves the design accuracy and reliability assurance capability of high-current grounding systems.

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the design process of the high-reliability high-current grounding system of this invention. Figure 2 This is a flowchart illustrating the layered, multi-level mesh grounding topology design of the present invention. Figure 3 This is a flowchart illustrating the design process of the gradient composite material conductive structure of the present invention. Figure 4 This is a flowchart illustrating the vibration-resistant, corrosion-resistant, and highly reliable connection design of the present invention. Figure 5 This is a flowchart illustrating the embedded intelligent state perception and health management design of the present invention. Figure 6 This is a flowchart of the high-current impact optimization design based on multiphysics simulation of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be described in more detail below with reference to the accompanying drawings.

[0024] In the accompanying drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present invention.

[0025] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] The following is in conjunction with the appendix Figure 1-6 The embodiments of the present invention will be described in detail below.

[0027] Example 1 This invention discloses a high-reliability high-current grounding system, which includes: The main network, with conductive medium laid along the main load-bearing structure of the aircraft, forms a low-impedance main discharge channel; Regional networks are constructed around the backbone network nodes in areas where aircraft equipment is concentrated, creating local low-impedance grounding ring networks. Device local network, where a single device or group of devices is connected to the device's dedicated grounding terminal in the local area network.

[0028] Furthermore, the main grounding network is arranged on the symmetrical plane of the aircraft, ensuring good multi-point overlap with the metal skin of the aircraft.

[0029] Furthermore, the conductive medium is a continuous copper alloy strip with high conductivity and high strength or a silver-plated copper braided strip. Ring networks use thinner but more flexible conductors and are connected to the main network in a star or grid pattern. The grounding terminal uses a grounding stake or grounding bar, and its location is an equipotential bonding point.

[0030] Furthermore, gradient composite materials are used as the material for the grounding terminal lap surface at critical equipment grounding connection points and areas susceptible to high current surges in the local network of the equipment. The gradient composite material consists of a conductive layer, a transition layer, and a structural layer, all of which are integrally molded.

[0031] Furthermore, the surface of the grounding connection material is treated, and a connection process is adopted to achieve zero fretting corrosion and constant low contact resistance at the connection point; The surface treatment refers to applying a multi-layer composite coating to the connection interface; The connection process includes: Solid-state welding is used for critical permanent joints, employing cold metal transfer welding or friction welding to form a metallurgical bond. Use high-reliability bolt connections. For connection points requiring maintenance, use anti-loosening self-locking nuts / bolts, along with spring washers and external toothed locking washers, to apply precise and controllable torque and maintain constant clamping force. Apply conductive, antioxidant, and anti-fretting corrosion grease to the bolt threads and contact surfaces. Use dedicated spring / strap contact finger connectors for parts that require frequent plugging and unplugging or where there is relative movement. Use spring or strap contact finger grounding connectors with multi-point elastic contact.

[0032] Furthermore, temperature sensors and micro-resistance measurement modules are embedded in key nodes of the backbone network, busbars of regional networks, and grounding terminals of important equipment; and miniature accelerometers are deployed near key connection points in vibration-prone areas to monitor vibration intensity.

[0033] Furthermore, miniaturized, low-power sensor networks are integrated into the grounding system to enable real-time online monitoring of key parameters of the grounding system and real-time assessment of the health status of the grounding point.

[0034] Example 2 This invention discloses a design method for a high-reliability high-current grounding system, which includes the following steps: 1. Layered multi-level mesh grounding topology design Instead of traditional single-point or simple bus grounding, a three-level hierarchical mesh structure of "backbone network - regional network - device local network" is constructed.

[0035] Main grounding design scheme: High-conductivity, high-strength continuous copper alloy strips or silver-plated copper braided strips are laid along the main load-bearing structures such as the frame beams at the fuselage and wings to form a low-impedance main discharge channel. This main grounding is preferably arranged on the symmetrical plane of the helicopter or fixed-wing aircraft, and good multi-point overlap with the metal skin of the helicopter or fixed-wing aircraft (as a secondary discharge path) is ensured.

[0036] Regional network grounding design scheme: In areas where major equipment is concentrated (such as the cockpit control panel, equipment compartments, engine compartments, landing gear compartments, etc.), a local low-impedance grounding ring network is constructed around the backbone network nodes. This ring network uses a slightly thinner but more flexible conductor (such as tinned copper braided tape) and is connected to the backbone network in a star or grid pattern.

[0037] Equipment local network grounding design scheme: Individual equipment or equipment groups should be connected to the nearest equipment-specific grounding stake, grounding busbar, or other location within the regional network. These grounding stakes and busbars should be designed as equipotential bonding points to prevent the formation of grounding loops between equipment.

[0038] By implementing a hierarchical, multi-level mesh grounding topology design, multiple parallel discharge paths can be provided, greatly reducing the risk of single-point failure; optimizing current distribution and reducing local overheating; reducing overall loop impedance; and improving system redundancy.

[0039] 2. Design of conductive structures using gradient composite materials Innovative functional graded composite materials are used at grounding connection points of critical equipment and in areas susceptible to high current impacts (such as near lightning strike points).

[0040] The material consists of three layers: a conductive layer (highly conductive metals such as copper and silver), a transition layer (high thermal conductivity and high strength metal matrix composites such as copper / graphene), and a structural layer (lightweight and high-strength composites such as CFRP and metal matrix composites). It is integrally formed through special processes (such as diffusion welding, hot isostatic pressing, and additive manufacturing).

[0041] The conductive layer faces the current inflow direction to ensure low contact resistance and low ohmic loss; the transition layer achieves excellent thermal conductivity and mechanical bonding between the conductive layer and the structural layer, rapidly dissipating Joule heat and avoiding localized ablation; the structural layer provides the main mechanical strength and the connection interface with the body structure, meeting the requirements for lightweighting.

[0042] By using a gradient composite material conductive structure design, the ablation problem caused by heat concentration under high current can be solved; the mechanical strength and fatigue resistance of the connection points can be significantly improved; and the functions of electrical conductivity, thermal conductivity and structural load-bearing can be integrated, reducing weight.

[0043] 3. Vibration-resistant, corrosion-resistant, and highly reliable connection design The surface of the grounding connection material is treated, and a special connection process is used to achieve zero fretting corrosion and constant low contact resistance at the connection point.

[0044] Surface treatment method: The connection interface (conductor terminals and connection surface) adopts a multi-layer composite plating (such as a nickel base layer to prevent diffusion, a silver or tin middle layer to provide high conductivity and oxidation resistance, and a thin gold layer on the surface to enhance corrosion resistance).

[0045] Connection process design scheme: (1) Solid-state welding treatment: For key permanent connection points (such as the connection between the main network and the body structure), cold metal transition welding or friction welding should be given priority to form a metallurgical bond and completely eliminate the possibility of mechanical loosening.

[0046] (2) Use high-reliability bolt connections. For connection points requiring maintenance, use anti-loosening self-locking nuts / bolts, along with spring washers and external toothed locking washers, to apply precise and controllable torque and maintain constant clamping force. Apply conductive, anti-oxidation, and anti-fretting corrosion grease to the bolt threads and contact surfaces.

[0047] (3) Use dedicated spring / strap contact finger connectors. In areas where frequent plugging and unplugging or relative movement is required, use spring or strap contact finger grounding connectors with multi-point elastic contact to ensure stable contact pressure and excellent vibration resistance.

[0048] Through a vibration-resistant, corrosion-resistant, and highly reliable connection design, it can fundamentally suppress loosening and fretting corrosion caused by vibration; maintain stable low contact resistance over a long period of time; and improve the environmental adaptability and lifespan of the connection points.

[0049] 4. Embedded Intelligent Status Perception and Health Management Design By integrating miniaturized, low-power sensor networks into the grounding system, real-time online monitoring of key parameters (temperature, contact resistance, vibration) of the grounding system can be achieved.

[0050] Low-power temperature sensors and milliohm-level four-wire micro-resistance measurement modules are embedded in key nodes of the backbone network, busbars of regional networks, and grounding terminals of important equipment. Miniature accelerometers are deployed near key connection points in vibration-prone areas to monitor vibration intensity.

[0051] Sensor data is transmitted to the machine's health management system via a low-bandwidth bus (such as CAN or a dedicated line). The health management system has a built-in intelligent diagnostic algorithm that, based on baseline models and trends of temperature, resistance, and vibration data, can assess the health status of the grounding point in real time, predict potential faults (such as loose connections or accelerated corrosion), and issue early warnings.

[0052] By incorporating intelligent state perception and health management design, grounding system maintenance can be transformed from scheduled maintenance to condition-based maintenance, reducing operating costs; potential hazards can be detected in advance to avoid catastrophic failures; and system performance degradation data can be provided to support design optimization.

[0053] 5. High-current impact optimization design based on multiphysics simulation During the design phase, electromagnetic-thermal-structural strongly coupled transient multiphysics simulations of high-current impulse grounding systems are employed to accurately simulate the dynamic behavior of lightning strikes or high-current impulses within the grounding system. A high-fidelity digital model is established, incorporating detailed geometry, material properties, and interface characteristics. Typical severe high-current impulse waveforms or short-circuit current waveforms conforming to aerospace standards (such as DO-160 / SAE ARP5412) are applied to simulate and analyze the impact on the grounding system under these conditions.

[0054] The simulation analysis primarily focuses on changes in parameters such as current density distribution, Joule heating and transient temperature rise, electromagnetic force effects, and thermal stress. Current density distribution parameters are used to identify hotspots where current accumulates; Joule heating and transient temperature rise are used to predict whether the maximum temperature exceeds material limits; and electromagnetic force effects are used to assess whether the electrodynamic forces generated by high currents cause conductor deformation or mechanical damage to connection points. Thermal stress is analyzed to examine the thermal stress caused by rapid temperature rises and its impact on structural integrity. Based on the simulation results, the conductor cross-sectional area, shape, orientation, connection point location and number, and gradient material design are iteratively optimized to ensure that the temperature rise, electrodynamic forces, and thermal stress in any part of the grounding system remain within safety margins throughout the entire high-current process.

[0055] High-current impact optimization design based on multiphysics simulation can avoid potential failure risks during the design stage and improve the success rate of the design; it can achieve accurate design of materials and structures through simulation optimization, avoiding the weight cost caused by over-design; and it provides strong theoretical guidance for physical experiments.

[0056] The key innovations of this invention are summarized as follows: 1. Layered multi-level mesh grounding topology design: Provides redundant, low-impedance, and distributed optimized current discharge paths, significantly improving system robustness.

[0057] 2. Gradient composite material conductive structure design: This innovatively solves the problem of local overheating and ablation under high current impact, while achieving both lightweight and high strength.

[0058] 3. Vibration-resistant, corrosion-resistant, and highly reliable connection design: Through a combination of advanced surface treatment and solid-state welding / high-reliability mechanical connection, fretting corrosion and loosening are completely suppressed, ensuring the lifelong reliability of the connection points.

[0059] 4. Embedded intelligent status perception and health management design: Realizes real-time online monitoring and health status assessment of key system parameters (temperature, resistance, vibration) to achieve predictive maintenance.

[0060] 5. High-current impact optimization design based on multiphysics simulation: Through simulation analysis, high-current operating conditions are accurately simulated in the design stage, and targeted optimization is carried out to ensure the safety and reliability of the system in real high-current events and reduce the iterative cost of physical experiments.

[0061] Thus, the objective of this invention has been achieved.

[0062] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high reliability high current grounding system, characterized by, include: The main network, with conductive medium laid along the main load-bearing structure of the aircraft, forms a low-impedance main discharge channel; Regional networks are constructed around the backbone network nodes in areas where aircraft equipment is concentrated, creating local low-impedance grounding ring networks. Device local network, where a single device or group of devices is connected to the device's dedicated grounding terminal in the local area network.

2. The high reliability high current grounding system of claim 1, wherein, The main grounding network is arranged on the symmetrical plane of the aircraft, and good multi-point overlap with the metal skin of the aircraft is ensured.

3. The high reliability high current grounding system of claim 1, wherein, The conductive medium is a continuous copper alloy strip with high conductivity and high strength or a silver-plated copper braided strip; Ring networks use thinner but more flexible conductors and are connected to the main network in a star or grid pattern. The grounding terminal uses a grounding stake or grounding bar, and its location is an equipotential bonding point.

4. The high reliability high current grounding system of claim 1, wherein, Gradient composite materials are used as the material for the grounding terminal lap surface in critical equipment grounding connection points and areas susceptible to high current surges in the local network of the equipment. The gradient composite material consists of a conductive layer, a transition layer, and a structural layer, all of which are integrally molded.

5. The high reliability high current grounding system of claim 1, wherein, The surface of the grounding connection material is treated, and a connection process is used to achieve zero fretting corrosion and constant low contact resistance at the connection point; The surface treatment refers to applying a multi-layer composite coating to the connection interface; The connection process includes: Solid-state welding is used for critical permanent joints, employing cold metal transfer welding or friction welding to form a metallurgical bond. Use high-reliability bolt connections. For connection points requiring maintenance, use anti-loosening self-locking nuts / bolts, along with spring washers and external toothed locking washers, to apply precise and controllable torque and maintain constant clamping force. Apply conductive, antioxidant, and anti-fretting corrosion grease to the bolt threads and contact surfaces. Use dedicated spring / strap contact finger connectors for parts that require frequent plugging and unplugging or where there is relative movement. Use spring or strap contact finger grounding connectors with multi-point elastic contact.

6. The high reliability high current grounding system of claim 1, wherein, Temperature sensors and micro-resistance measurement modules are embedded in key nodes of the main network, busbars of regional networks, and grounding terminals of important equipment; miniature accelerometers are deployed near key connection points in vibration-prone areas to monitor vibration intensity.

7. The high reliability high current grounding system of claim 6, wherein, By integrating miniaturized, low-power sensor networks into the grounding system, real-time online monitoring of key parameters of the grounding system can be achieved, and the health status of the grounding point can be assessed in real time.

8. A high reliability high current grounding system design method, characterized by, Includes the following steps: Arrange the main grounding channel according to the equipment grounding requirements, equipment location, and machine structure; Based on the concentrated equipment area, grounding area channels are arranged around the main channel nodes; Based on the equipment's grounding requirements, a dedicated grounding terminal is installed for the equipment and connected to the grounding area channel as close as possible.

9. The design method for a high-reliability high-current grounding system according to claim 8, characterized in that, Establish a digital model of the grounding system that includes detailed geometry, material properties, and interface characteristics; Apply typical severe high-current surge waveforms or short-circuit current waveforms; Output grounding system parameters including temperature rise, electrodynamic force, and thermal stress. The grounding system should be optimized based on the above parameters.

10. The high reliability high current grounding system design method of claim 9, wherein, Current density distribution parameters are used to identify hotspots where current accumulates. By analyzing Joule heating and transient temperature rise, we can predict whether the maximum temperature exceeds the material's limit. The electromagnetic force effect is used to assess whether the electrodynamic force generated by a large current causes conductor deformation or mechanical damage to the connection point. By thermal stresses, the thermal stresses caused by the rapid temperature rise and their influence on the structural integrity can be analyzed.

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