温湿度致编织碳纤维复合材料车体结构性能劣化及机理研究

Deterioration mechanism and influence of temperature and humidity on structural performance of braided CFRP carbody

为确定温湿度对碳纤维复合材料车体结构强度性能的影响机制,以HF10/EM119平纹编织碳纤维预浸料为原材料,制备复合材料层合板样件,开展低温干态、常温干态、高温干态和高温湿态4种温湿度环境下的层合板拉伸、压缩和面内剪切实验,得到不同环境条件下的材料力学参数;基于环境叠加验证方法,计算各温湿度环境下,某型号高速磁浮编织碳纤维复合材料车体的模态和静强度,并与标准环境下的仿真结果对比。研究结果表明:在温湿环境下,编织复合材料层合板的拉伸、压缩和剪切性能均有一定程度劣化,极限强度劣化程度显著大于模量劣化程度;低温干态环境(-30℃,相对湿度(55±10)%)和高温湿态环境(80℃,相对湿度(85±5)%)致劣程度尤其明显,将显著削弱车体结构刚度,改变车体结构高阶模态振型,继而引起列车本构强度减损,降低车体承载能力。

In order to determine the influence mechanisms of temperature and humidity on the structural strength properties of carbon fiber composites carbody,carbon fiber prepreg reinforced by HF10/EM119 plain fabrics was used as raw materials to prepare composite laminates.Tensile,compression and in-plane shear tests were conducted under four temperature and humidity conditions,i.e.,low temperature and low humidity,room temperature and low humidity,elevated temperature and low humidity and elevated temperature and high humidity.The material parameters in each environment were obtained.Then,the modal and static strength for a high-speed maglev CFRP carbody were simulated using the verification method of environmental superposition.The predicted results were then compared with those in standard environment.The results show that the tensile,compressive and shear properties of braided composite laminates are decreased and the degradation effect of the ultimate strength is greater than that of modulus.The deterioration degree of at low temperature and low humidity(-30℃,relative humidity of(55±10)%)and elevated temperature and high humidity(80℃,relative humidity of(85±5)%)is particularly obvious,which will significantly reduce the stiffness of the carbody structure and change the high-order vibration mode,and thereby weaken the constitutive strength and carrying capacity of the carbody.