The creep fatigue testing machine is a key equipment in the field of modern material mechanics performance evaluation, mainly used to simulate the failure behavior of materials under the combined action of high temperature, continuous load, and cyclic load. It is widely used in key fields such as aerospace, energy, and chemical engineering.
1、 Working principle: Composite load of static and dynamic
Its working principle is the complex superposition of creep and fatigue physical mechanisms.
Creep mechanism simulation: The device first applies a constant static load (lower than the yield strength of the material) on the specimen and places it in a controllable high-temperature environment. Under continuous stress and high temperature, atoms inside the material will undergo diffusion, dislocation slip, and climb, resulting in slow and continuous plastic deformation over time, known as creep deformation.
Fatigue mechanism simulation: On top of this constant load "background", the testing machine uses a precise servo control system to superimpose a periodic dynamic cyclic load (such as tension tension or tension compression load). This alternating stress can trigger the initiation and propagation of microcracks within the material.
The core is that the static creep process at high temperatures accelerates the propagation of fatigue microcracks, while periodic dynamic fatigue loads intensify the formation and connection of creep voids. The mutual promotion between the two significantly reduces the lifespan of the material, thus accurately reproducing the damage accumulation and failure process of the component under actual working conditions.
2、 Technical features: high precision and high complexity
To achieve the complex working principle mentioned above, this type of testing machine has the following significant technical features:
High precision composite loading capability: Using advanced servo motors or electro-hydraulic servo control systems, it can accurately and stably output constant static loads and dynamic loads of multiple waveforms (such as sine waves and triangular waves) simultaneously, ensuring long-term stability and accuracy of load control.
Precise high-temperature environment simulation: Equipped with high-performance high-temperature furnaces or environmental chambers, it can maintain temperature uniformity and stability for a long time (temperature control accuracy can reach ± 1 ° C~± 2 ° C), which is a prerequisite for obtaining reliable creep data.
Advanced deformation measurement system: Integrated with high-precision extensometers, it not only needs to measure the total strain caused by cyclic loading, but also needs to be able to distinguish and record the creep strain that slowly increases over time, which requires the resolution and resistance to high temperature interference of the measurement system.
Complex security protection and data analysis: Due to the extremely long testing cycle (up to thousands of hours), the equipment must have complete safety interlock, overload protection, and unmanned operation capabilities. Its software system is capable of real-time recording, processing, and analyzing multi parameter data such as load, temperature, strain, and time, providing key basis for life prediction models.
In summary, the creep fatigue testing machine, through its precise multi axis loading, high-temperature environment control, and measurement system, deeply reveals the failure mechanism of materials under harsh service conditions, and is a scientific research tool for modern industrial equipment safety design and life assessment.