Russian Journal of Forensic MedicineRussian Journal of Forensic MedicineСудебная медицина2411-87292409-4161Eco-Vector1617510.17816/fm16175Technical reportsТехнические отчеты技术报告Research ArticleOnline tool for finite element analysis of postmortem convective heat transfer of the headОнлайн-инструмент конечно-элементного анализа посмертного конвективного теплообмена головы基于有限元分析的死后头部对流热交换在线工具https://orcid.org/0009-0007-7542-72352407-7937NedugivVladimir G.НедуговВладимир ГермановичNedugivVladimir G.
Russian Federation
nedugovvg@gmail.comhttps://orcid.org/0000-0002-7380-37663828-8091NedugovGerman V.НедуговГерман ВладимировичNedugovGerman V.
Russian Federation

MD, Dr. Sci. (Medicine), Assistant Professor

д-р мед. наук, доцент

MD, Dr. Sci. (Medicine), Assistant Professor

nedugovh@mail.ruSamara National Research UniversityСамарский национальный исследовательский университет имени академика С.П. КоролеваSamara National Research UniversitySamara State Medical UniversityСамарский государственный медицинский университетSamara State Medical University13122024291220241045555650708202401102024Copyright ©; 2024, Eco-VectorCopyright ©; 2024, Эко-ВекторCopyright ©; 2024,2024Eco-VectorЭко-Векторhttps://creativecommons.org/licenses/by-nc-nd/4.0/https://for-medex.ru/jour/article/view/16175

Background: One of the most promising modern approaches in thermometric diagnosis for estimating the time of death is the finite element analysis method of postmortem heat transfer. This method overcomes the limitations of phenomenological cooling equations for corpses. However, the software packages enabling this method are typically expensive and require users to independently set up task parameters. This article introduces an open-access online tool with a simple interface for finite element analysis of postmortem convective heat transfer of the human head. The tool is designed to determine the time of death through cranioencephalic thermometry of the corpse.

Aim: To develop an online tool for finite element analysis of postmortem convective heat transfer of the head.

Materials and methods: A scalable finite element model of the head, approximated as a multi-layered sphere, was created. The model consists of 1,311 nodes and 9,277 finite elements. A computational algorithm was developed to calculate the initial and postmortem temperature fields of the head using the Python 3.

Results: The Simple Finite Element Model of Postmortem Convective Heat Transfer of the Head online application was developed. It considers the specifics of the initial temperature field, dimensions and thermophysical properties of the primary anatomical layers of the head, intensity of convective heat transfer, diagnostic point coordinates, and variations in external temperature during the cooling process. The application generates cooling curves at the diagnostic point and the head surface during the first 24 hours postmortem, providing numerical data, geometric and mesh properties, and temperature distribution along the integration contour from the model’s center to the diagnostic point.

Conclusion: The developed solver requires neither high-performance computer systems nor specialized user training. This feature makes the proposed online tool applicable in forensic practice for determining the time of death using cranioencephalic thermometry of corpses.

Обоснование. Одним из наиболее перспективных современных направлений в области термометрической диагностики давности наступления смерти является метод конечно-элементного анализа посмертного теплообмена, позволяющий преодолеть ограничения, присущие феноменологическим уравнениям охлаждения трупа. Однако обеспечивающие данный метод программные пакеты характеризуются высокой стоимостью, а также предполагают наличие у пользователя навыков самостоятельного задания условий решаемых задач. В настоящей статье предложен открытый онлайн-инструмент конечно-элементного анализа посмертного конвективного теплообмена головы человека с простым интерфейсом, предназначенный для определения давности наступления смерти путём краниоэнцефальной термометрии трупа.

Цель работы ― разработка онлайн-инструмента конечно-элементного анализа посмертного конвективного теплообмена головы.

Материалы и методы. Построена масштабируемая конечно-элементная модель головы, аппроксимированная многослойным шаром, состоящая из 1311 узлов и 9277 конечных элементов. Разработан вычислительный алгоритм поиска начального и посмертного температурного поля головы, реализованный на языке программирования Python 3.

Результаты. Разработано онлайн-приложение Simple Finite Element Model of Postmortem Convective Heat Transfer of the Head, учитывающее особенности начального температурного поля, размеры и теплофизические свойства основных анатомических слоёв головы, интенсивность конвективного теплообмена, координаты диагностической точки и изменения внешней температуры в процессе охлаждения трупа. Результатом работы онлайн-приложения являются визуализация кривых охлаждения в диагностической точке и на поверхности головы в первые сутки посмертного периода с генерацией соответствующих числовых значений, а также вывод информации о геометрии и свойствах сетки конечно-элементной модели и распределении температуры вдоль контура интегрирования от центра модели до диагностической точки.

Заключение. Отсутствие у разработанного решателя высоких требований к системным характеристикам компьютера и специальной подготовке пользователя позволяет применять предложенное онлайн-приложение в судебно-медицинской экспертной практике при установлении давности наступления смерти путём краниоэнцефальной термометрии трупа.

背景。在确定死亡时间的热测诊断领域，死后热交换的有限元分析方法是一种前景广阔的技术。相比传统的尸体冷却现象学方程，该方法能够克服其局限性。然而，目前支持这一方法的软件通常价格昂贵，并要求用户具备独立设置求解条件的能力。本文提出了一种开放式在线工具，用于基于头部颅脑热测的尸体冷却有限元分析，具有简洁的界面，可用于确定死亡时间。

研究目的。开发一个用于分析死后头部对流热交换的有限元分析在线工具。

材料与方法。构建了一个可缩放的有限元头部模型，该模型以多层球体为近似，包含1311个节点和9277个有限元。开发了用于计算初始和死后头部温度场的算法，并以Python 3编程语言实现。

研究结果。开发了在线应用程序Simple Finite Element Model of Postmortem Convective Heat Transfer of the Head，其功能包括：考虑初始温度场的特性；头部主要解剖层的尺寸和热物理特性；对流热交换强度；诊断点坐标；尸体冷却过程中外部温度的变化。该工具能够生成诊断点和头部表面在死后24小时内的冷却曲线，并输出相关数值结果。此外，还可显示有限元模型的网格几何特性、温度沿从模型中心到诊断点积分路径的分布情况。

结论。该计算在线工具无需高性能计算机或用户具备专业知识，可在法医学实践中用于通过颅脑热测法确定尸体死亡时间。

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