What is the difference between the elastic modulus of carbon fiber composites and steel materials?

With the advancement and development of science and technology, people have begun to pursue high-performance materials with light weight and high strength. With the emergence of carbon fiber composite materials, traditional metal materials are gradually being replaced in some fields. In this paper, the elastic modulus of carbon fiber composites and steel are compared and analyzed to see what are the differences.

First of all, let's understand the elastic modulus. The elastic modulus is also called Young's modulus and tensile modulus. It refers to the strength of the material to resist deformation under pressure under a certain stress. Many people call it rigidity of the material. , the symbol E is its unit of measurement.

The elastic modulus of the entire material is calculated as E = (F/A) + (dL/l) = σ + ε. Here F is the applied force, A represents the force area of the material, d is the offset (change) of the material length along the measurement axis (m or in), and L is the original dimension of  the material.

The elastic modulus of carbon fiber products is also related to the size and structure of the product, so it is more about the elastic modulus of the raw materials. The following is a comparison of the elastic modulus of carbon fiber raw materials and steel raw materials.

Taking T300 carbon fiber as an example, its elastic modulus is 230GPa, T700 carbon fiber elastic modulus is 240GPa, the density of carbon fiber material is 1.6~2.0g/cm^3, tensile strength is 3000MPa, elongation at break is 1.5%, specific heat capacity is 0.7 ~0.9KJ/(Kg.K), thermal expansion coefficient -0.5x10-6/℃, resistivity 0.00075~0.0015Ω.cm, and also has the characteristics of high temperature resistance, ablation resistance, waterproof and radiation resistance.

Among the rigid materials, the common cold-rolled steel is used as an example for comparison. The elastic modulus of cold-rolled steel is 180GPa, the density is 7.85g/cm^3, the tensile strength is 300~600MPa, the elastic modulus is 190GPa, and the specific heat capacity is 0.42KJ/ (kg.K), elongation 16%~23%, thermal expansion coefficient 10.6~12.2x10-6/℃.

From the above data, it is not difficult to find that the elastic modulus of carbon fiber is higher than that of rigid elastic modulus, but the advantages are not particularly obvious. However, considering the advantages of density and strength, including thermal expansion coefficient, it can be found that carbon fiber products can indeed replace metal products. , the strength can reach four times that of steel, and the quality is only one-fifth of that of steel, which can very well achieve lightweight products.