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Economics of Composites 2015 Edition, September 17, 2015
Description / Abstract:
Introduction
When we examine the “economics of composites” issue (as this book does), it is good to go back and start with the basics and a brief review of the composites industry. A brief review of where we came from helps us understand some of the factors involved in our topic (“economics of composites”) and get a better perspective on where we need to go to achieve a more attractive case for implementation of composites. So we will start with the basics. The generally accepted definition of composite is:
“A combination of at least two (2) materials differing in form or composition and when they are combined, they create a material with properties that cannot be achieved by either of the component materials acting alone.”
Based on this definition, concrete would be considered a “composite” as it is composed of stone and cement. Wood is a “natural” composite as it is a combination of resin and wood fiber. Today’s aerospace composites are a combination of man-made materials (resins and fibers).
Widespread use of composites is known to have started in the 1930s. Then, boat hulls were first designed and manufactured using fiberglass composite materials. By the end of WW II, use of fiberglass composites had grown substantially. Union Carbide Corporation was the first known company to pursue development of carbon fiber materials. Processes for producing carbon fiber were developed in the early 1960s. Since the introduction of carbon fiber, this industry has had a steady growth rate that continues to this day. This book will primarily focus on carbon fiber composites—mostly on carbon fiber composites for aerospace/aircraft applications that have broadened to include many other industries, products, and applications. Other industries that use composite materials or have potential for significant use of composites will also be discussed.
The term “low-cost composites” has often been described as a contradiction in terms, as composites have not historically been considered low cost in any of the variety of applications that utilize composite materials. This is especially true in aerospace/ aircraft-related composites. Although composites provide many advantages over metals in aircraft applications (including lighter weight, fatigue resistance, and better damage tolerance), the cost associated with replacing metals with composites can make this change a difficult decision.
Throughout the history of the composites industry (primarily the carbon fiber composites industry), the expression “composites are lighter than aluminum and stronger than steel” has often been heard. Specifically, carbon fiber composites have better stiffness, strength, and fatigue resistance than metals. Therefore, composites have a lot of advantages for many applications that have typically been made with metals. This is especially true for applications where weight is a critical factor. Weight reductions were a primary consideration when composites were first used in the aerospace/aircraft industry. For the space launch industry, weight savings in a launch vehicle enabled more payload than could be put into orbit, so the weight savings provided by using composites were very valuable. For commercial aircraft, weight reductions achieved by using composites in the airframe enabled lower operating cost (fuel burn) and higher passenger loads. Also, lower maintenance costs were achieved, as composites do not corrode, and they are fatigue resistant, so major maintenance cycles (D-Check) on an airframe with a significant amount of composites are not required as frequently as an aircraft made mostly of metal structure. As reported in Aviation Week magazine, Boeing estimated that using composite materials for primary structural components on the new 787 commercial aircraft would provide a 32% maintenance cost savings after 10 years of service. This maintenance cost comparison was with a 767 aircraft that is mostly aluminum structure. For military aircraft, weight savings provided by use of composites enabled more ordinance loads, lower maintenance costs, and also contributed to “stealth” of the airframe.
When considering the advantages associated with using carbon fiber composites for a variety of applications (especially aircraft applications), why has the change to composites been a slow, decades-long process for many industries? There are several reasons for this slow transition to composites in the aerospace industry. For example, in the commercial aircraft industry, caution was a primary factor. Aircraft companies that design and build commercial aircraft were very cautious and reluctant to change materials on an aircraft intended to carry a large number of passengers. Also, design engineers had decades of experience and data regarding designing airframes with aluminum. Designing aircraft structures with composite materials was a new experience, and composites did not have nearly the amount of design data as metals. There was also a comfort factor with aluminum designs, so early composite structure designs tended to be “black aluminum.” Such designs did not take advantage of co-cure assembly instead of fastener assembly and the ability to make parts larger with composites instead of assembling several smaller parts. These black aluminum designs also contributed to the cost of composite aircraft structure.
When we examine the “economics of composites” issue (as this book does), it is good to go back and start with the basics and a brief review of the composites industry. A brief review of where we came from helps us understand some of the factors involved in our topic (“economics of composites”) and get a better perspective on where we need to go to achieve a more attractive case for implementation of composites. So we will start with the basics. The generally accepted definition of composite is:
“A combination of at least two (2) materials differing in form or composition and when they are combined, they create a material with properties that cannot be achieved by either of the component materials acting alone.”
Based on this definition, concrete would be considered a “composite” as it is composed of stone and cement. Wood is a “natural” composite as it is a combination of resin and wood fiber. Today’s aerospace composites are a combination of man-made materials (resins and fibers).
Widespread use of composites is known to have started in the 1930s. Then, boat hulls were first designed and manufactured using fiberglass composite materials. By the end of WW II, use of fiberglass composites had grown substantially. Union Carbide Corporation was the first known company to pursue development of carbon fiber materials. Processes for producing carbon fiber were developed in the early 1960s. Since the introduction of carbon fiber, this industry has had a steady growth rate that continues to this day. This book will primarily focus on carbon fiber composites—mostly on carbon fiber composites for aerospace/aircraft applications that have broadened to include many other industries, products, and applications. Other industries that use composite materials or have potential for significant use of composites will also be discussed.
The term “low-cost composites” has often been described as a contradiction in terms, as composites have not historically been considered low cost in any of the variety of applications that utilize composite materials. This is especially true in aerospace/ aircraft-related composites. Although composites provide many advantages over metals in aircraft applications (including lighter weight, fatigue resistance, and better damage tolerance), the cost associated with replacing metals with composites can make this change a difficult decision.
Throughout the history of the composites industry (primarily the carbon fiber composites industry), the expression “composites are lighter than aluminum and stronger than steel” has often been heard. Specifically, carbon fiber composites have better stiffness, strength, and fatigue resistance than metals. Therefore, composites have a lot of advantages for many applications that have typically been made with metals. This is especially true for applications where weight is a critical factor. Weight reductions were a primary consideration when composites were first used in the aerospace/aircraft industry. For the space launch industry, weight savings in a launch vehicle enabled more payload than could be put into orbit, so the weight savings provided by using composites were very valuable. For commercial aircraft, weight reductions achieved by using composites in the airframe enabled lower operating cost (fuel burn) and higher passenger loads. Also, lower maintenance costs were achieved, as composites do not corrode, and they are fatigue resistant, so major maintenance cycles (D-Check) on an airframe with a significant amount of composites are not required as frequently as an aircraft made mostly of metal structure. As reported in Aviation Week magazine, Boeing estimated that using composite materials for primary structural components on the new 787 commercial aircraft would provide a 32% maintenance cost savings after 10 years of service. This maintenance cost comparison was with a 767 aircraft that is mostly aluminum structure. For military aircraft, weight savings provided by use of composites enabled more ordinance loads, lower maintenance costs, and also contributed to “stealth” of the airframe.
When considering the advantages associated with using carbon fiber composites for a variety of applications (especially aircraft applications), why has the change to composites been a slow, decades-long process for many industries? There are several reasons for this slow transition to composites in the aerospace industry. For example, in the commercial aircraft industry, caution was a primary factor. Aircraft companies that design and build commercial aircraft were very cautious and reluctant to change materials on an aircraft intended to carry a large number of passengers. Also, design engineers had decades of experience and data regarding designing airframes with aluminum. Designing aircraft structures with composite materials was a new experience, and composites did not have nearly the amount of design data as metals. There was also a comfort factor with aluminum designs, so early composite structure designs tended to be “black aluminum.” Such designs did not take advantage of co-cure assembly instead of fastener assembly and the ability to make parts larger with composites instead of assembling several smaller parts. These black aluminum designs also contributed to the cost of composite aircraft structure.
Economics of Composites 2015 Edition, September 17, 2015