Study on Properties Prediction and Braiding Optimization of Axial Braided Carbon/Carbon Composite

Materials Science-Poland

Tian

Zhang

2021

Self Cite

In order to study the influencing factors of the tensile properties of axial braided C/C composites, the interfacial shear strength of the fiber rod and matrix was studied and ejecting tests of the fiber rod were carried out. The ejecting test specimens were formed with different thicknesses to obtain the changing rule of the interface shear strength with the thickness of the sample, and the testing method for the interface shear strength of the axial braided C/C composite material. The results show that the recommended thickness of the ejecting test specimens for the interface shear strength of is four times the diameter of the fiber rod. The interface shear strength distribution law of two different batches of materials was obtained through the interface ejecting test. The mesoscopic structure characteristics and pore statistical distribution law of the hole surface after ejecting were analyzed by scanning electron microscopy (SEM), and the mechanism of the difference of the interface shear strength was obtained. The tensile properties of two different batches of materials were obtained by tensile tests. The results show that the tensile properties of the two batches of materials differ greatly. The analysis suggests that the reason for this difference is the differences in interfacial bonding strength between the fiber rod and matrix. The higher the interface shear strength, the better the tensile property of the material will be.

Section: Axial Braided C/c Composite Materialsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on factors of interface properties of axial braided C/C composite materials

Materials Science-Poland

Tian

Zhang

2021

Self Cite

“…The load conditions that the grain in solid rocket motor (SRM) experiences during the stages from production to flight are temperature load in the stage of propellant solidify, gravity load in storage stage, inner pressure when a motor is in working process, and the inertia load in the flight stage [1,2]. Given that the grain structure is rationally designed, when the comprehensive mechanical properties of propellants are good or the working temperature is not very low, the structural integrity of grain usually can be ensured under the working pressure [3]. Also, the influence from the case stiffness is not obvious, and the case design can meet the requirement of the internal pressure strength will be enough [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

The Influence Factors of Grain Integrity under the Internal Pressure Condition in SRM

International Journal of Aerospace Engineering

Tian

2021

Self Cite

To investigate the influence factors of propellant grain integrity under the internal pressure, the cylindrical grain was equivalent to a thick-wall cylinder and its three-dimension stress-strain problem was solved. Under the internal and external pressure, the strain and displacement equations of the inside thick-wall cylinder were expressed, and then, the stress and strain expressions of grain were obtained. On this basis, the hoop strain equations on the inside surface of the cylindrical grain and case were developed. The hoop strain on the inner surface of the grain can be predicted by the hoop strain of the case cylinder via the strain equations, and therefore, the hoop strain in the inner surface can be indirectly monitored in real time during the working process of the motor. The hoop strain in the inner surface of grain can be effectively reduced by increasing the case stiffness or decreasing the m number of the grain.

“…C/C composite material is a carbon fiber reinforced carbon matrix composite material. The reinforcing phase and the matrix phase are both structural composites composed of pure carbon with special properties [1][2][3][4]. It has high specific strength, good thermal stability, wear resistance, ablative resistance, and a series of excellent properties, especially its mechanical properties with the increase of temperature strength does not fall but rise, so that it has been widely used in the aerospace field [5,6].…”

Section: Introductionmentioning

confidence: 99%

Study on Mechanical Properties and Failure Mechanism of Axial Braided C/C Composite

International Journal of Aerospace Engineering

Tian²,

Tang³

2021

Self Cite

In order to study the mechanical properties and failure mechanism of the axial braided C/C composites, the microscopic and macroscopic mechanical properties of the composite were investigated. In view of the size effect of the samples, the properties of the samples with different thickness were tested. The strain during loading was measured by optical method, and the failure morphology was observed by SEM. The changing characteristics of stress-strain curve were analyzed, and the failure characteristics of materials and failure mechanism under various loads were obtained. It was found that brittle fracture was observed during the tensile process of axial braided C/C composites, and the main failure forms were fiber rod pulling and partial fiber rod breaking in the axial direction. Radial failure was mainly in the form of fiber bundle fracture and crack stratification propagation. When compressed, the material exhibited pseudoplastic characteristics. The radial compression sample was cut along a 45-degree bevel. The axial compression curve was in the form of double fold, the axial fiber rod was unstable, and the transverse fiber bundle was cut. During in-plane shearing, the axial fracture was brittle and the fiber rod was cut. The radial direction showed the fracture and pulling of the fiber bundle, and the material had the characteristics of pseudoplasticity. The research methods and results in this paper could provide important references for the optimization and rational application of C/C composite materials.