Electromagnetic Reinforced Carbon Fiber Composite Case and Its Electromagnetic Pulse Protection Performance

We adopt the technology of electromagnetic strengthening carbon fiber composite material to improve its electromagnetic protection ability, and use it to prepare the sample of carbon fiber composite cabinet, through the test, it has good electromagnetic pulse protection performance. Based on the carbon fiber composite structure design and electric connection design of the interlamination and gap electromagnetic enforcement. The HEMP protection performance was tested under the GB/T18039.10-2018 standard and the results showed that the HEMP shielding efficiency were above 65 dB. The carbon fiber composite cabinet had the lightweight ,high strength，HEMP shielding and anti-severe environment characteristics. The carbon fiber composite cabinet has a project value and application prospect

Accelerated microwave curing of fibre-reinforced thermoset polymer composites for structural applications: A review of scientific challenges

Accelerated curing of high performance fibre-reinforced polymer (FRP) composites via microwave heating or radiation, which can significantly reduce cure time and increase energy efficiency, has several major challenges (e.g. uneven depth of radiation penetration, reinforcing fibre shielding, uneven curing, introduction of hot spots etc). This article reviews the current scientific challenges with microwave curing of FRP composites considering the underlying physics of microwave radiation absorption in thermoset-matrix composites. The fundamental principles behind efficient accelerated curing of composites using microwave radiation heating are reviewed and presented, especially focusing on the relation between penetration depth, microwave frequency, dielectric properties and cure degree. Based on this review, major factors influencing microwave curing of thermoset-matrix composites are identified, and recommendations for efficient cure cycle design are provided

Characterization and modelling of electromagnetic interactions in aircraft

This article describes the development of modelling techniques and simulation tools for the electromagnetic (EM) analysis of aircraft. It is shown that hybrid solvers and multi-scale techniques can be used effectively to analyse the EM response of aircraft. The importance of supplementing models with appropriate measurement and characterization techniques for parameter extraction and for validation is also demonstrated

Damage Detection Response Characteristics of Open Circuit Resonant (SansEC) Sensors

The capability to assess the current or future state of the health of an aircraft to improve safety, availability, and reliability while reducing maintenance costs has been a continuous goal for decades. Many companies, commercial entities, and academic institutions have become interested in Integrated Vehicle Health Management (IVHM) and a growing effort of research into "smart" vehicle sensing systems has emerged. Methods to detect damage to aircraft materials and structures have historically relied on visual inspection during pre-flight or post-flight operations by flight and ground crews. More quantitative non-destructive investigations with various instruments and sensors have traditionally been performed when the aircraft is out of operational service during major scheduled maintenance. Through the use of reliable sensors coupled with data monitoring, data mining, and data analysis techniques, the health state of a vehicle can be detected in-situ. NASA Langley Research Center (LaRC) is developing a composite aircraft skin damage detection method and system based on open circuit SansEC (Sans Electric Connection) sensor technology. Composite materials are increasingly used in modern aircraft for reducing weight, improving fuel efficiency, and enhancing the overall design, performance, and manufacturability of airborne vehicles. Materials such as fiberglass reinforced composites (FRC) and carbon-fiber-reinforced polymers (CFRP) are being used to great advantage in airframes, wings, engine nacelles, turbine blades, fairings, fuselage structures, empennage structures, control surfaces and aircraft skins. SansEC sensor technology is a new technical framework for designing, powering, and interrogating sensors to detect various types of damage in composite materials. The source cause of the in-service damage (lightning strike, impact damage, material fatigue, etc.) to the aircraft composite is not relevant. The sensor will detect damage independent of the cause. Damage in composite material is generally associated with a localized change in material permittivity and/or conductivity. These changes are sensed using SansEC. The unique electrical signatures (amplitude, frequency, bandwidth, and phase) are used for damage detection and diagnosis. An operational system and method would incorporate a SansEC sensor array on select areas of the aircraft exterior surfaces to form a "Smart skin" sensing surface. In this paper a new method and system for aircraft in-situ damage detection and diagnosis is presented. Experimental test results on seeded fault damage coupons and computational modeling simulation results are presented. NASA LaRC has demonstrated with individual sensors that SansEC sensors can be effectively used for in-situ composite damage detection of delamination, voids, fractures, and rips. Keywords: Damage Detection, Composites, Integrated Vehicle Health Monitoring (IVHM), Aviation Safety, SansEC Sensor

Improving Electromagnetic Shielding with Metallic Nanoparticles

Due to major advantages (e.g. weight saving, maintenance advantages), the airframe manufacturers use more and more Polymer Matrix Composites (PMCs) in different parts of aircraft structures. But PMCs have the substantial disadvantage of low conductivity and therefore low Electromagnetic (EM) Shielding. Electromagnetic Interference (EMI) sources are all around and inside aircraft and can potentially threaten the immunity of the aircraft. Metallic meshes have been used to overcome this deficiency. However at high frequencies (UHF, SHF), most of the metallic mesh loses the performance. Regrettably most of the present and upcoming systems onboard of aircraft are functional in the mentioned range of frequencies. Furthermore, passengers are using more and more Personal Electronic Devices (PEDs) onboard of aircraft. Interference caused by PEDs are also in the same range of frequencies. Measured susceptibility caused by PEDs is higher in composite aircraft comparing to metallic one. To develop this disadvantage of composite aircrafts, design of a new lightweight shield, particularly for aeronautic applications, is needed. Metallic nanoparticles have a great potential to be used as new EM shields for aerospace applications. The promising results of this work encourage the designers to use metallic nanoparticles as a new shield for protection of composite aircrafts

Tecniche di protezione da interferenze elettromagnetiche: modellistica e prove sperimentali in camera riverberante

Electromagnetic interference and compatibility are problems that claim an increasing attention in many environments, all over the world

NASA SBIR abstracts of 1991 phase 1 projects

The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included

EMI Shields made from intercalated graphite composites

Electromagnetic interference (EMI) shielding typically makes up about twenty percent of the mass of a spacecraft power system. Graphite fiber/polymer composites have significantly lower densities and higher strengths than aluminum, the present material of choice for EMI shields, but they lack the electrical conductivity that enables acceptable shielding effectiveness. Bromine intercalated pitch-based graphite/epoxy composites have conductivities fifty times higher than conventional structural graphite fibers. Calculations are presented which indicate that EMI shields made from such composites can have sufficient shielding at less than 20% of the mass of conventional aluminum shields. EMI shields provide many functions other than EMI shielding including physical protection, thermal management, and shielding from ionizing radiation. Intercalated graphite composites perform well in these areas also. Mechanically, they have much higher specific strength and modulus than aluminum. They also have shorter half thicknesses for x-rays and gamma radiation than aluminum. Thermally, they distribute infra-red radiation by absorbing and re-radiating it rather than concentrating it by reflection as aluminum does. The prospects for intercalated graphite fiber/polymer composites for EMI shielding are encouraging