Author name: GULSHAN SHAFI

Fiber Orientation Angle is an Arctan of fiber orientation vector components.The formula is given by: Where: θ is the fiber orientation angle. X and Y are the respective components of the fiber orientation vector.  

Critical Fiber Volume Fraction is a Minimum fibers to prevent crack propagation.The formula is given by: Where: Vf∗​ is the critical fiber volume fraction. KIC​ is the fracture toughness of the composite material. σf​ is the tensile strength of the fibers. L is the characteristic length associated with crack growth.

Matrix Strength Efficiency Factor is a Composite matrix strength relative to individual.The formula is given by: Where: η is the matrix strength efficiency factor. σmatrix, composite​ is the strength of the matrix in the composite material. σmatrix, individual​ is the strength of the matrix material individually.

Strain Energy Release Rate is an Energy per unit area during crack propagation.The formula is given by: Where: G is the strain energy release rate. dW is the change in potential energy. dA is the change in crack area.

The efficiency of fiber strength in a composite compared to individual fibers.The formula is given by: Where: σfc  is a stress fiber composite. σfi  is a stress fiber individual.

Matrix Toughness is a Resistance to crack propagation in composite matrix.The formula is given by: Where: KIc​ is the fracture toughness of the matrix. σf​ is the ultimate tensile strength of the matrix material. c is a constant related to the crack geometry and specimen configuration.

Fiber Aspect Ratio is a Length relative to diameter for reinforcement. The formula is given by: Where: Aspect Ratio is the dimensionless ratio representing the fiber’s length-to-diameter ratio. Fiber Length is the length of the fiber. Fiber Diameter is the diameter of the fiber.

Interlaminar Shear Strength is a Resistance to shearing forces between laminate layers.The formula is given by: Where: τinterlaminar​ is the interlaminar shear strength. F is the applied force required to shear the material. A is the cross-sectional area over which the force is applied.

Hygrothermal Expansion is a Measures dimensional changes in composite laminates due to moisture and temperature.The formula is given by: Where: εtotal​ is the total strain. εthermal is the thermal strain. εmoisture​ is the moisture-induced strain.

Delamination Growth Rate is a Measures the rate of interlayer separation. The formula is given by: Where: dt/dA​ is the rate of change of delamination area. KI​ is the stress intensity factor. ΔG is the change in the energy release rate.