Brands D W, Bovendeerd P H, Peters G W, Wismans J S
Eindhoven University of Technology, Eindhoven, The Netherlands.
Stapp Car Crash J. 2000 Nov;44:249-60. doi: 10.4271/2000-01-SC17.
The large strain dynamic behaviour of brain tissue and silicone gel, a brain substitute material used in mechanical head models, was compared. The non-linear shear strain behaviour was characterised using stress relaxation experiments. Brain tissue showed significant shear softening for strains above 1% (approximately 30% softening for shear strains up to 20%) while the time relaxation behaviour was nearly strain independent. Silicone gel behaved as a linear viscoelastic solid for all strains tested (up to 50%) and frequencies up to 461 Hz. As a result, the large strain time dependent behaviour of both materials could be derived for frequencies up to 1000 Hz from small strain oscillatory experiments and application of Time Temperature Superpositioning. It was concluded that silicone gel material parameters are in the same range as those of brain tissue. Nevertheless the brain tissue response will not be captured exactly due to increased viscous damping at high frequencies and the absence of shear softening in the silicone gel. For trend studies and benchmarking of numerical models the gel can be a good model material.
比较了脑组织和硅胶（一种用于机械头部模型的脑替代材料）的大应变动态行为。使用应力松弛实验对非线性剪切应变行为进行了表征。脑组织在应变高于1%时表现出显著的剪切软化（对于高达20%的剪切应变，软化约30%），而时间松弛行为几乎与应变无关。对于所有测试应变（高达50%）和高达461 Hz的频率，硅胶表现为线性粘弹性固体。因此，通过小应变振荡实验和时间温度叠加法的应用，可以得出两种材料在高达1000 Hz频率下的大应变时间相关行为。得出的结论是，硅胶材料参数与脑组织的参数在同一范围内。然而，由于高频下粘性阻尼增加以及硅胶中不存在剪切软化，脑组织的响应无法被精确捕捉。对于数值模型的趋势研究和基准测试，该凝胶可以是一种很好的模型材料。
