Data from: Model sensitivity and use of the comparative finite element method in mammalian jaw mechanics: mandible performance in the Gray Wolf

Finite Element Analysis (FEA) is a powerful tool gaining use in studies of biological form and function. This method is particularly conducive to studies of extinct and fossilized organisms, as models can be assigned properties that approximate living tissues. In disciplines where model validation is difficult or impossible, the choice of model parameters and their effects on the results become increasingly important, especially in comparing outputs to infer function. To evaluate the extent to which performance measures are affected by initial model input, we tested the sensitivity of bite force, strain energy, and stress to changes in seven parameters that are required in testing craniodental function with FEA. Simulations were performed on FE models of a Gray Wolf (Canis lupus) mandible. Results showed that unilateral bite force outputs are least affected by the relative ratios of the balancing and working muscles, but only ratios above 0.5 provided balancing-working side joint reaction force relationships that are consistent with experimental data. The constraints modeled at the bite point had the greatest effect on bite force output, but the most appropriate constraint may depend on the study question. Strain energy is least affected by variation in bite point constraint, but larger variations in strain energy values are observed in models with different number of tetrahedral elements, masticatory muscle ratios and muscle subgroups present, and number of material properties. These findings indicate that performance measures are differentially affected by variation in initial model parameters. In the absence of validated input values, FE models can nevertheless provide robust comparisons if these parameters are standardized within a given study to minimize variation that arise during the model-building process. Sensitivity tests incorporated into the study design not only aid in the interpretation of simulation results, but can also provide additional insights on form and function.有限元分析（Finite Element Analysis, FEA）是一种功能强大的工具，目前在生物形态与功能研究中的应用愈发广泛。该方法尤其适用于已灭绝和化石生物的相关研究，因为可为模型赋予近似活体组织的属性。在模型验证难以实现或无法开展的学科领域中，模型参数的选择及其对结果的影响愈发关键，尤其是在通过对比输出结果推断生物功能的场景中。为评估初始模型输入对性能指标的影响程度，我们测试了咬合力、应变能与应力对7项参数变化的敏感性——这些参数是利用FEA研究颅齿功能时的必需参数。本研究基于灰狼（Canis lupus）下颌骨的有限元模型开展模拟实验。研究结果显示，单侧咬合力的输出受平衡侧与工作侧肌肉相对比例的影响最小，但仅当该比例高于0.5时，平衡侧-工作侧关节反力的关系才与实验数据相符。咬合点处的约束条件对咬合力输出的影响最大，但最适配的约束方式或许取决于具体的研究问题。应变能受咬合点约束变化的影响最小，但在四面体单元数量、咀嚼肌比例、肌肉亚组构成以及材料属性数量存在差异的模型中，应变能值的波动幅度更大。上述发现表明，不同的性能指标对初始模型参数变化的敏感性存在差异。即便缺乏经过验证的输入参数值，只要在特定研究中统一这些参数以尽可能降低建模过程中产生的差异，有限元模型仍可提供可靠的对比分析结果。将敏感性测试纳入研究设计，不仅有助于解读模拟实验的结果，还能为生物形态与功能的研究提供额外的见解。