Finite element-based injury metrics for pulmonary contusion via concurrent model optimization.
Finite element-based injury metrics for pulmonary contusion via concurrent model optimization.
复制标题
通过并发模型优化基于有限元的肺挫伤损伤指标。
DOI：
10.1007/s10237-010-0251-5
复制
发表时间：
2011
影响因子：
3.5
通讯作者：
Stitzel,JoelD
中科院分区：
文献类型：
--
作者：
Gayzik,FScott;Hoth,JJason;Stitzel,JoelD
本研究利用大鼠撞击伤模型，探讨了四种撞击条件下撞击严重度与肺挫伤（PC）之间的关系。从有限元（FE）模型的肺的力-偏转响应，同时匹配的实验数据，通过遗传算法优化不同的影响。Sprague-Dawley大鼠在撞击前接受右侧胸廓切开术。通过装有仪器的活塞将损伤直接施加到肺。测试了五个队列：假手术组和四个经历不同严重程度肺损伤的组。各组的撞击速度（V）和穿透深度（D）值分别为第1组（V= 6.0 m · s-1，D= 5.0 mm）、第2组（V= 1.5 m · s-1，D= 5.0 mm）、第3组（V= 6 m · s-1，D= 2.0 mm）和第4组（V= 1.5 m · s-1，D= 2.0 mm）。在损伤后24小时、48小时和1周获得CT扫描。通过分割确定挫伤体积。基于观察到的挫伤体积和第一主应变，在撞击后24小时和1周确定PC的基于FE的损伤指标。在撞击后24小时，严重撞击组的高不透射线性肺（HRL）体积最大（平均HRL = 9.21 ± 4.89），并且显著大于除第3组以外的所有其他队列。对于第1组（能量= 3.88 ± 0.883 mJ，观察到的与4.47 mJ，模拟的）和第2组（能量= 1.46 ± 0.403 mJ，观察到的与1.50 mJ，模拟的）冲击，并行优化在一个标准差内匹配模拟和观察到的冲击能量。HRL和冲击能量之间的统计显着的关系。在挫伤后24小时，基于FEA的损伤指标超过94.5 s-1，ε max超过0.284，超过470 s-1。还确定了在撞击后1周仍然存在的肺损伤的证据。ε max超过0.343，ε max超过573 s-1。网格敏感性研究发现，基于应变率的阈值比仅基于应变的阈值对网格密度的变化更敏感。
This study explores the relationship between impact severity and resulting pulmonary contusion (PC) for four impact conditions using a rat model of the injury. The force–deflection response from a Finite Element (FE) model of the lung was simultaneously matched to experimental data from distinct impacts via a genetic algorithm optimization. Sprague-Dawley rats underwent right-side thoracotomy prior to impact. Insults were applied directly to the lung via an instrumented piston. Five cohorts were tested: a sham group and four groups experiencing lung insults of varying degrees of severity. The values for impact velocity (V) and penetration depth (D) of the cohorts were Group 1, (V= 6.0 m · s−1,D= 5.0 mm), Group 2, (V= 1.5 m · s−1,D= 5.0 mm), Group 3, (V= 6 m · s−1,D= 2.0 mm), and Group 4, (V= 1.5 m · s−1,D= 2.0 mm). CT scans were acquired at 24 h, 48 h, and 1 week post-insult. Contusion volume was determined through segmentation. FE-based injury metrics for PC were determined at 24 h and 1 week post-impact, based on the observed volume of contusion and first principal strain. At 24 h post-impact, the volume of high radiopacity lung (HRL) was greatest for the severe impact group (mean HRL = 9.21 ± 4.89) and was significantly greater than all other cohorts but Group 3. The concurrent optimization matched simulated and observed impact energy within one standard deviation for Group 1 (energy = 3.88 ± 0.883 mJ, observed vs. 4.47 mJ, simulated) and Group 2 (energy = 1.46 ± 0.403 mJ, observed vs. 1.50 mJ, simulated) impacts. Statistically significant relationships between HRL and impact energy are presented. The FEA-based injury metrics at 24 h post-contusion areexceeding 94.5 s−1,εmaxexceeding 0.284 andexceeding 470 s−1. Thresholds for injury to the lung still present at 1 week post-impact were also determined. They areexceeding 149 s−1,εmaxexceeding 0.343 andexceeding 573 s−1. A mesh sensitivity study found that thresholds based on strain rate were more sensitive to changes to mesh density than the threshold based on strain only.