复合材料复杂环境效应加速试验设计及评估方法

Accelerated Test Design and Evaluation Method of Composites Considering Complex Environmental Effects

目的指导复合材料在复杂湿热环境下环境适应性摸底与评价试验的开展,分析评估复合材料在复杂综合应力下的激活能参数。方法分析装备全寿命周期复杂自然环境剖面及各环境因素影响效应,确定复合材料各工作阶段敏感应力类型及条件,基于应力加速模型及累积损伤等原理,制定复合材料复杂环境效应综合加速试验剖面。构建复合材料复杂环境条件下的动力学模型,并提出相应参数估计方法。开展复合材料加速试验,并基于实测数据开展复合材料性能退化建模与评估。结果分析了复合材料全寿命周期环境影响因素及环境效应,明确了各工作阶段敏感应力主要有温度、湿度、太阳辐照、温度交变、振动以及冲击等。依据实际环境数据,设计并开展了3组不同湿热条件(80℃/75%RH、80℃/85%RH、80℃/95%RH)的综合试验,收集得到复合材料拉伸强度、拉剪强度、径向弯曲强度以及纬向弯曲强度等4种性能指标的试验数据。试验数据表明,拉剪强度(最大相对退化速率为0.1773/循环)、径向弯曲强度(最大相对退化速率为0.1292/循环)以及纬向弯曲强度(最大相对退化速率为0.2610/循环)等性能参数可用于产品退化建模与评估。通过参数估计,进一步确定了退化速率与湿热应力的关系,并针对当前试验提供了改进依据。结论复杂环境效应综合加速试验对装备复合材料产品经历复杂环境条件的模拟效果和加速效果较好,试验可实施性较强。提出的改进广义Eyring模型可涵盖温度应力与湿热应力的加速效应,并综合考虑多种应力的相互作用,通过少量组合试验便可量化评估激活能等参数。所建模型指出当前基于激活能参考值(Ea=0.7eV)试验方案可由不同温度应力的综合试验数据进一步修正与优化,且所提试验与分析方法主要针对大部分树脂基复合材料产品,并可依据需要推广至电子产品、机电产品等试验对象。

The work aims to guide the development of environmental adaptability mapping and evaluation tests of compos-ites in complex hygrothermal environments,and to analyze and evaluate the activation energy parameters of composites under complex comprehensive stresses.In this paper,the complex environment profile and the effects of environmental factors during the whole life cycle of the equipment were analyzed,and the types and magnitude of sensitive stresses in each working stage of composites were determined.A dynamic model of composites under complex environmental conditions was constructed and corresponding parameter estimation methods were proposed.Accelerated tests of composites were carried out,and degradation modeling and evaluation of composite properties were carried out based on measured data.By analyzing the environmental ef-fects of various environmental factors in the whole life cycle of the composites,the temperature,hygrothermal stress,solar irra-diation,cycling temperature,vibration and shock in each working stage were regarded as the sensitive stresses.According to the actual environmental data,three sets of comprehensive environmental acceleration tests under different hygrothermal conditions(80℃/75%RH,80℃/85%RH,80℃/95%RH)were designed and carried out,and the test data of tensile strength,tensile shear strength,radial bending strength and zonal bending strength of composite were collected.The test data showed that tensile shear strength(the maximum relative degradation rate was 0.1773/cycle),radial bending strength(the maximum relative degradation rate was 0.1292/cycle)and zonal bending strength(the maximum relative degradation rate was 0.2610/cycle)could be used for product degradation modeling and evaluation.The relationship between degradation modeling rate and hygrothermal stress and thermal stress was further determined by parameter estimation.The basis for improvement was provided according to the current test.The comprehensive accelerated test can simulate and accelerate the complex environment experienced by the equipment composite products,and the test can be implemented.The improved generalized Eyring model can cover the acceleration effect of temperature stress and humidity thermal stress,and give comprehensive consideration to the interaction of multiple stresses.Parameters such as activation energy can be quantified by a small number of combination tests.The model indicates that the current test scheme based on reference activation energy(Ea=0.7 eV)can be further modified and optimized by the comprehen-sive test data of different temperature stresses.The proposed test and analysis method can be applied to most resin matrix com-posite products,and can be extended to electronic products,mechanical and electrical products and other test objects as required.