Thermal Impulse Response Analysis of Element Arrays in Flexible Electronic Devices
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摘要: 柔性电子器件在工作时产生的热量,导致元件发生变形,极易影响其功能性. 本研究建立了柔性电子器件元件阵列热脉冲响应的有限元分析模型,探讨了柔性电子器件元件封装层与基底层的层厚比对整体结构热稳定性的影响,以及柔性电子器件元件的热脉冲响应. 初步得到:当热脉冲载荷从50 W/m2增大至150 W/m2时,功能层中心单元温度上升约0.47%,热应力增大约25.87%;若封装层与基底层的层厚比从0.2增大到5.0,功能层中心单元的热应力降低约92%,热应变降低约99%,沿层厚方向的位移降低约86%. 初步结果可为柔性电子器件元件热脉冲载荷的优化设计和防护提供基础数据.
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关键词:
- 柔性电子器件元件阵列 /
- 热脉冲响应 /
- 温度场 /
- 热应力 /
- 有限元分析
Abstract: The heat generated by flexible electronic devices during operation leads to deformation of the components, which is highly likely to affect their functionality. A finite element analysis model for the thermal impulse responses of the flexible electronic device element arrays were established, and the effects of the layer thickness ratio of the encapsulation layer to the substrate layer of the flexible electronic device element on the thermal stability of the overall structure, as well as the thermal impulse responses of the flexible electronic device components, were investigated. The results show that, the temperature of the functional layer center element rises by about 0.47% and the thermal stress increases by about 25.87% with the thermal impulse load increasing from 50 W/m2 to 150 W/m2. With the layer thickness ratio of the encapsulation layer to the substrate layer increasing from 0.2 to 5.0, the thermal stress of the functional layer center unit decreases by about 92%, the thermal strain decreases by about 99%, and the displacement along the layer thickness decreases by about 86%. The work provides basic data for the optimization design and protection against thermal impulse loading on flexible electronic device components. -
表 1 材料属性
Table 1. Material properties
material elastic modulus /GPa Poisson’s ratio density /(kg·m-3) coefficient of thermal expansion /℃-1 conductivity /(W·m-1·℃-1) heat capacity /(J·℃-1) SU-8 2 0.17 1 200 5.20×10-5 0.2 1.20×109 Si 130 0.28 2 330 2.60×10-6 160 7.00×108 Cu 110 0.34 8 960 1.67×10-5 401 3.84×108 PDMS 0.002 0.49 965 3.10×10-4 0.17 1.46×109 表 2 柔性电子器件元件的几何参数
Table 2. Geometric parameters of flexible electronic device components
parameter a b hSU-8 hPDMS aSi bSi hSi l RCu hCu bCu value /mm 25 25 0.5 2.5 2.5 2.5 0.5 5 1 0.05 0.5 表 3 超弹性材料参数
Table 3. Hyperelastic material parameters
表 4 本文热力耦合有限元模型的不同单元数算例
Table 4. Cases of different meshes for the presented thermally coupled finite element model
example SU-8 Si Cu PDMS total mesh 1 38 400 400 1 588 38 400 99 456 mesh 2 44 800 400 1 588 44 800 112 256 mesh 3 64 800 720 1 921 64 800 159 132 mesh 4 80 000 720 1 921 80 000 189 532 表 5 封装层与基底层不同层厚比下的算例
Table 5. The cases with different thickness ratios of the encapsulation layer to the substrate layer
example hSU-8/mm hSi/mm hPDMS/mm η type 1 0.5 0.5 2.5 0.2 type 2 1.0 0.5 2.0 0.5 type 3 1.5 0.5 1.5 1.0 type 4 2.0 0.5 1.0 2.0 type 5 2.5 0.5 0.5 5.0 -
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