层压板小质量物体冲击下接触力测量与损伤响应

Contact Force Measurement and Response to Damage of Composite Laminates Subjected to Small-mass Impact

为了发展复合材料层压板在小质量物体冲击下损伤性能的测试技术,研发了小质量冲击试验机,可模拟自由状态小质量物体产生的冲击,冲击能量可调节,冲击点挠度可测量。通过冲击头加速度和冲击点挠度测量接触力,结果显示,加速度传感器谐振会明显干扰测量信号。采用滤波技术后,冲击头的加速度响应可以有效地测量冲击接触力。用冲击点挠度计算接触力,结果也与试验结果吻合。对层压板进行多个能量下的冲击试验,发现产生明显分层损伤时,由加速度传感器测得的接触力在特定值处明显下降,随后可能继续升高;由冲击点挠度得到的接触力斜率发生变化,这可作为小质量冲击分层阈值力的识别方法。

To develop the technology of test on damage resistance of laminates subjected to small mass impact,a test instrument of small mass impact was designed and manufactured. The instrument provided free impact due to small mass. The impact energy was adjustable,and the deflection of the impact point could be recorded. The contact force was measured with the acceleration of the impactor and the plate deflection of impact point respectively. It is shown that the signal is disturbed by the resonance of the accelerometer. The contact force could be obtained with the filtered signals of the acceleration of the impactor. Based on the analytical model of small mass impact,the contact force measured through the deflection is in good agreement with the experimental one. The impacts with variant energy were conducted on the laminates. It shows that the contact force from the accelerometer drops at a special value in test that the distinct damage is generated,then the force may increase again. The contact force obtains from the deflection changes the slop. They can be used to identify the delamination threshold load of small mass impact.