Browse Topic: Advanced composite materials
ABSTRACT Design for structural topology optimization is a method of distributing material within a design domain of prescribed dimensions. This domain is discretized into a large number of elements in which the optimization algorithm removes, adds, or maintains the amount of material. The resulting structure maximizes a prescribed mechanical performance while satisfying functional and geometric constraints. Among different topology optimization algorithms, the hybrid cellular automaton (HCA) method has proven to be efficient and robust in problems involving large, plastic deformations. The HCA method has been used to design energy absorbing structures subject to crash impact. The goal of this investigation is to extend the use of the HCA algorithm to the design of an advanced composite armor (ACA) system subject to a blast load. The ACA model utilized consists of two phases: ceramic and metallic. In this work, the proposed algorithm drives the optimal distribution of a metallic phase
To save on fuel and reduce aircraft emissions, engineers are looking to build lighter, stronger airplanes out of advanced composites. These engineered materials are made from high-performance fibers that are embedded in polymer sheets. The sheets can be stacked and pressed into one multilayered material and made into extremely lightweight and durable structures
In research that may lead to advancements in the design of next-generation airplane and spacecraft, MIT engineers used carbon nanotubes to prevent cracking in multilayered composites. Massachusetts Institute of Technology, Cambridge, MA To save on fuel and reduce aircraft emissions, engineers are looking to build lighter, stronger airplanes out of advanced composites. These engineered materials are made from high-performance fibers that are embedded in polymer sheets. The sheets can be stacked and pressed into one multilayered material and made into extremely lightweight and durable structures. But composite materials have one main vulnerability: the space between layers, which is typically filled with polymer “glue” to bond the layers together. In the event of an impact or strike, cracks can easily spread between layers and weaken the material, even though there may be no visible damage to the layers themselves. Over time, as these hidden cracks spread between layers, the composite
Composite materials play an important role in aerospace manufacturing. The light weight, durability and ability to create complex shapes from molds make these materials ideal for frames and structural components that enable lighter, more fuel-efficient aircraft. While composite structures can weigh up to 20 percent less than their metal counterparts, these materials can often be more difficult to machine. The extremely abrasive nature of carbon fiber reinforced polymers (CFRPs) will wear down standard cutting tools more quickly than almost any other material. A standard carbide cutting tool may only hold up to cutting a few feet of CFRPs before its dimensional stability fails, while in traditional metal machining that same tool might last 20 to 50 times that before wearing out
Recycling of advanced composites made from carbon fibers in epoxy resins is required for two primary reasons. First, the energy necessary to produce carbon fibers is very high and therefore reusing these fibers could greatly reduce the lifecycle energy of components which use them. Second, if the material is allowed to break down in the environment, it will contribute to the growing presence of microplastics and other synthetic pollutants. Currently, recycling and safe methods of disposal typically do not aim for full circularity, but rather separate fibers for successive downcycling while combusting the matrix in a clean burning process. Breakdown of the matrix, without damaging the carbon fibers, can be achieved by pyrolysis, fluidized bed processes, or chemical solvolysis. The major challenge is to align fibers into unidirectional tows of real value in high-performance composites
Additive manufacturing (AM) is currently being used to produce many aerospace components, with its inherent design flexibility enabling an array of unique and novel possibilities. But, in order to grow the application space of polymer AM, the industry has to provide an offering with improved mechanical properties. Several entities are working toward introducing continuous fibers embedded into either a thermoplastic or thermoset resin system. This approach can enable significant improvement in mechanical properties and could be what is needed to open new and exciting applications within the aerospace industry. However, as the technology begins to mature, there are a couple of unsettled issues that are beginning to come to light. The most common question raised is whether composite AM can achieve the performance of traditional composite manufacturing. If AM cannot reach this level, is there enough application potential to warrant the development investment? The answers are highly
Fly ash is a light byproduct produced when pulverized coal is burnt in suspension-fueled furnaces in power plants. Separating the recovered fly ash from the exhaust gases. Due to its distinct physical and chemical properties, it is utilized in a wide variety of industrial and building applications. These applications include the production of cement and concrete, the stabilization of liquid waste, and hydraulic mining backfill. Fly ash has the potential to enhance the physical and mechanical properties of aluminum castings, as well as reduce their costs and increase their densities, all while lowering their prices. This research investigated the effect of fly ash incorporation on the mechanical properties of the aluminum casting alloy ZA8. Investigated were the cast and heat-treated varieties of unreinforced ZA8 and its metal matrix composite of 15% ferrous, 20% nickel, 10% fly ash, and 10% magnesium carbide. According to the results, the quantity of fly ash in the melt affected the
The U.S. Army fields a multitude of aircraft mission design series (MDS) developed by several different original equipment manufacturers with varying mission requirements and flight profiles. The structural analysis in this work assumes the materials, tooling, skillsets, and capabilities are organically available and proper at the repair location. Army Combat Capabilities Development Command, Redstone Arsenal, Alabama The U.S. Army operates and maintains several aircraft MDS to meet the warfighter's multidomain mission. Aircraft fielded by the U.S. Army originate from multiple equipment manufacturers. These aircraft include rotary-wing configurations such as the AH-64D/E Apache, CH-47F Chinook, and H-60A/L/V/M Blackhawk aircraft which significantly vary in mission parameters and flight profiles. These aircraft contain structures made from a majority aluminum, steel, and titanium alloys which have dominated aircraft designs for much of the history of powered flight. However, the use of
The U.S. Army operates and maintains several aircraft MDS to meet the warfighter’s multidomain mission. Aircraft fielded by the U.S. Army originate from multiple equipment manufacturers. These aircraft include rotary-wing configurations such as the AH-64D/E Apache, CH-47F Chinook, and H-60A/L/V/M Blackhawk aircraft which significantly vary in mission parameters and flight profiles. These aircraft contain structures made from a majority aluminum, steel, and titanium alloys which have dominated aircraft designs for much of the history of powered flight. However, the use of advanced composite material systems such as fiberglass, carbon, and aramid fiber reinforcement with high performance epoxy resins has steadily increased to optimize structural designs and improve mission capability
Innovators at NASA Johnson Space Center have developed a carbon fiber reinforced polymer (CFRP) sleeve, that, when fitted over a cylindrical Li-ion battery cell, can prevent cell-to-cell propagation by containing a thermal runaway (TR) event to the originating cell
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