Mechanical properties axial tensile strength

What comes out of the die An anisotropic- or orthotropic- oriented-type structure. This orientation will affect the mechanical properties. The tensile strength will increase in the axial direction and decrease in the transverse direction. The elongation (ductility) will generally be increased in the axial direction for brittle amorphous polymers. However, for ductile crystalline polymers the elongation in the transverse direction can be greater than in the oriented axial direction because of the reorientation of molecular chains that occurs with application of force. 

However, not only are there are no commonly-accepted design methodologies for tubular components comprised of advanced composites, at this time there are almost no mechanical test standards for any of these properties of tubular geometry ceramic composite components. In particular, for CMC tubes there is one standard for axial tensile strength that has been approved and published by ASTM as C1773-13 Standard Test Method for Monotonic Tensile Behavior of Continuous Fiber-Reinforced Advanced Ceramic Tubular Test Specimens at Ambient Temperature. ... 

Mechanical Property Testing. Mechanical tests were performed on both unirradiated and irradiated materials at -157°C, 24°C, and 121°C. Specimens were kept dry prior to testing in an environmental chamber mounted in a tensile testing machine. Tensile test specimens of [0]4, [10]4, [45]4, and [90]4 laminates were cut from 4-ply composite panels. All specimens were straight-sided coupons. For tension and shear tests the length/width aspect ratio was 8. For the compression tests the aspect ratio was 0.25 and the unsupported length was 0.64 cm. The [0]4 laminates were used to measure the ultimate tension and compression strength, Xit the axial... 

An impact modifier is a rubber phase dispersed in particulate form throughout the matrix of a polymer solid. Unlike plasticizers, the rubber particles retain their intrinsic properties as a separate phase. The glass transition temperature of the parent matrix is not lowered by the addition of an impact modifier. The rubber particles do two things to the parent matrix phase (2,3,4) they act as stress concentrators (i.e., a large strain will start in the matrix near the interface) and they enhance the multi-axiality in stress. As multiaxial tensile strength near the interface further enhances dilatation, which shortens the mechanical relaxation time, the otherwise brittle polymer solid of the matrix will undergo plastic deformation in the vicinities of the rubber particles. 

Another factor that dictates the mechanical performance of polymers is the appearance of chain orientation. In the case of fibers, it is customary to pre-stretch in order to achieve a high degree of orientation in the axial direction. In films or other profiles made by extrusion or injection molding, chain orientation is usually obtained in the flow (machine) direction. This is manifested by an increase in tensile strength and a decrease in elongation in the machine direction, while the opposite is trae in the transverse direction. This calls for measurements in both directions. In two-dimensional objects this phenomenon is undesirable, as it leads to asymmetric properties (anisotropy). Similar behavior may be found in reinforced materials (with long fibers), in... 

Mechanical Properties of Various Nanocelluloses Obtained from Different Sources Elastic Modulus in Axial Direction (GPa) Elastic Modulus in Transverse Direction (GPa) Tensile Strength (Tensile Testing) (GPa)... 

Table 5.4 presents the mechanical properties of quasi-isotropic laminates having equal numbers of layers at 0°, -i-45°, -45°, and 90°. The elastic moduli of all quasi-isotropic laminates are the same for a given material. Note that the moduli and strengths are much lower than the axial properties of unidirectional laminates made of the same material. In many applications, laminate geometry is such that the maximum axial modulus and tensile and compressive strengths fall somewhere between axial unidirectional and quasi-isotropic values. 

Measuring mechanical properties of single electrospun nanofibres with above-mentioned techniques reveals a feamre in electrospun nanofibres that are different from their conventional counterparts. It has been found that axial modulus and ultimate tensile strength of electrospun polymeric nanofibres increase abmptly when the fibre diameter is below a certain value (Fig. 4.25) [229, 251-253]. 

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