在应变控制下,预制裂纹HTPB ((基终结聚乙烯) 推进剂的疲劳失效
Genfeng Li1, Bo Gao2, Hao Hu1
1School of Civil Engineering, ChongQing University of Arts and Sciences, ChongQing, 402160, China.
Scientific reports
|February 14, 2025
概括
基终结聚乙烯 (HTPB) 推进剂的疲劳寿命随着应变幅度的增加而显著降低. 有裂的有痕的HTPB推进剂的疲劳寿命比没有痕的标本更短.
科学领域:
- 材料科学 材料科学 材料科学
- 聚合物工程 聚合物工程
- 固体力学 固体力学是什么
背景情况:
- 基终结聚乙烯 (HTPB) 是固体推进剂中重要的聚合物粘合剂.
- 了解HTPB的疲劳行为对于确保火箭发动机的可靠性和安全性至关重要.
- 裂的存在可以显著影响材料的结构完整性和使用寿命.
研究的目的:
- 在应变控制条件下研究含有预制裂纹的HTPB推进剂的疲劳性能.
- 分析裂纹方向和应变幅度对疲劳寿命的影响.
- 探索热图温度变化,粘性弹性和疲劳行为之间的关系.
主要方法:
- 使用MTS疲劳测试机进行应变控制的疲劳测试.
- 准备好的HTPB推进剂样本在0°,45°和75°的角度有预制裂,加上没有的控制器.
- 在疲劳测试期间使用红外热像摄像头监测表面温度变化.
主要成果:
- 疲劳寿命随着恒定频率的延展幅度的增加而减少.
- 带有预制裂纹的标本表现出疲劳寿命约为2*10^4周期,而没有痕的标本持续了高达1*10^6周期.
- 观察到最终表面温度和疲劳寿命之间存在正相关性,这与粘弹性消散有关.
结论:
- 预制裂大大降低了HTPB推进剂的疲劳寿命,而不是与未划分的材料相比.
- HTPB的粘弹性特性有助于在循环负荷时产生热量,从而影响疲劳性能.
- 红外热学可以提供有关HTPB推进剂疲劳机制和材料降解过程的见解.
相关概念视频
Fatigue
171
Fatigue occurs when materials rupture under repeated or fluctuating loads, even at stress levels far below their static breaking strength. It typically results in brittle failure, even for ductile materials. It is a critical consideration in designing machines and structural components subjected to repetitive or varying loads. The nature of these loadings can range from fluctuating loads like unbalanced pump impellers causing vibrations to repeatedly bending a thin steel rod wire back and forth...
171
Fatigue Strength of Concrete
161
Fatigue, in the context of materials science and engineering, refers to the weakening or failure of a material caused by repeatedly applied loads, even if these loads are below the strength limit of the material. Fatigue strength in concrete is a critical property that influences its durability and longevity. Concrete can fail in two ways due to fatigue. Static fatigue or creep rupture occurs under a constant load or one that increases slowly. The other failure mode is due to cyclical or...
161
Microcracking in Concrete
99
Microcracking in concrete refers to the tiny cracks that can form within the material even before any external load is applied. These microcracks typically occur at the interface between the coarse aggregate and the hydrated cement paste, often as a result of differential volume changes prompted by variations in stress-strain behavior, as well as thermal and moisture movement. Initially, these microcracks remain stable and do not grow substantially until the concrete is stressed to about 30...
99
Yield Criteria for Ductile Materials under Plane Stress
140
In designing structural elements and machine parts using ductile materials, it is crucial to ensure that these components withstand applied stresses without yielding. Yielding is initially determined through a tensile test, which evaluates the material's response to uniaxial stress. However, tensile stress is insufficient when components face biaxial or plane stress conditions This condition requires advanced criteria to predict failure.
The Maximum Shearing Stress Criterion, also known as...
The Maximum Shearing Stress Criterion, also known as...
140
Plastic Behavior
185
A material's elastic behavior is characterized by the disappearance of stress once the load is removed, allowing the material to return to its original state. However, when stress surpasses the yield point, yielding commences, marking the onset of plastic deformation or permanent set. This change from elastic to plastic behavior is influenced by the peak stress value and the duration before the load is removed. An intriguing observation occurs when a specimen is loaded, unloaded, and...
185
Tensile Strength Considerations of Concrete
109
Considering the tensile strength of concrete involves recognizing that the theoretical strength of cement paste can be up to a thousand times higher than what is observed in practical applications. This significant discrepancy is largely attributed to the presence of microscopic cracks within the concrete. These cracks tend to amplify stress at their tips when a load is applied, a phenomenon explained by Griffith's theory of brittle fracture.
The dimensions and shape of a concrete specimen...
The dimensions and shape of a concrete specimen...
109


