Regarding the study on the fatigue life of phenyl vinyl silicone in low temperature environment, we can discuss it from the following aspects:

1. Research background and significance
Phenyl vinyl silicone, as a high-performance rubber material, is widely used in aerospace, automobile manufacturing, electronic appliances and other fields due to its unique chemical structure and physical properties. However, in low temperature environment, the performance of materials often changes significantly, especially fatigue life, which is crucial to ensure the reliability and safety of products. Therefore, it is of great significance to study the fatigue life of phenyl vinyl silicone in low temperature environment.

2. Research content and methods
Temperature range selection: The research is usually carried out within a certain low temperature range, such as -40℃ to 0℃ or lower, to simulate the extreme low temperature environment in actual application.
Dynamic stiffness and strain energy density: Under low temperature conditions, the dynamic stiffness and strain energy density of phenyl vinyl silicone are measured to evaluate the changes in its mechanical properties. As the temperature decreases, the dynamic stiffness of the material may increase, while the strain energy density may decrease.
Fatigue life test: By applying cyclic stress or strain, the actual use conditions of the material in a low temperature environment are simulated and its fatigue life is measured. Fatigue life is usually expressed as the number of cycles required for a material to reach a specific failure standard (such as crack extension to a certain length).
Fatigue life model verification: The experimental results are compared with the fatigue life calculation formula based on crack growth theory to verify the applicability and accuracy of the model in low temperature environment.

3. Research results and discussion
Dynamic stiffness and strain energy density changes: The study found that the dynamic stiffness of phenyl vinyl silicone usually increases with decreasing temperature, while the strain energy density may decrease. This may be due to the increase in the rigidity of the material molecular chain caused by low temperature, thereby improving the material's ability to resist deformation.
Fatigue life changes: In low temperature environments, the fatigue life of phenyl vinyl silicone may be affected by a variety of factors, including temperature, stress level, loading frequency, etc. In general, the fatigue life of the material may increase with decreasing temperature because low temperature helps to slow down the nucleation and propagation rate of cracks. However, this also depends on the specific formulation and processing conditions of the material.
Fatigue life model applicability: The fatigue life calculation formula based on crack growth theory may still have a certain applicability in low temperature environments, but it needs to be modified and adjusted for specific materials and experimental conditions. By verifying the degree of agreement between the experimental results and the calculated formula, the accuracy and reliability of the model can be further improved.

4. Conclusion and Prospect
In summary, the fatigue life study of phenyl vinyl silicone under low temperature environment is a complex and important topic. By deeply studying the changing laws of performance indicators such as dynamic stiffness, strain energy density and fatigue life of materials, it can provide strong theoretical support and practical guidance for the design, processing and application of materials. Future research can further explore the influence of different formulations and processing conditions on the low temperature fatigue performance of materials, and develop more accurate and reliable fatigue life prediction models.