This paper proposes a modification of the Forrestal-Warren perforation model aimed at extending its applicability range to intermediately-thick high-hardness armor steel plates.When impacted by armorpiercing projectil...This paper proposes a modification of the Forrestal-Warren perforation model aimed at extending its applicability range to intermediately-thick high-hardness armor steel plates.When impacted by armorpiercing projectiles,these plates tend to fail through adiabatic shear plugging which significantly reduces their ballistic resistance.To address this effect,an approach for determining effective thickness was defined and incorporated into the predictive model.Ballistic impact tests were performed to assess the modification's validity,in which ARMOX 500T steel plates were subjected to perpendicular impacts from 7.62×39 mm steel-cored rounds under various velocities.Frequent target failure by soft plugging was observed,as well as the brittle shatter of the hard steel core.Key properties of the recovered plugs including their mass,length and diameter were measured and reported along with the projectiles'residual velocities.Additionally,independent data from the open literature were included in the analysis for further validation.The original Forrestal-Warren model and the novel effective thickness modification were then used to establish the relationship between impact and residual velocities,as well as to determine the ballistic limit velocity.The comparison revealed that the proposed approach significantly improves the model's accuracy,showing a strong correlation with experimental data and reducing deviations to within a few percent.This enhancement highlights the potential of the effective thickness term,which could also be applied to other predictive models to extend their applicability range.Further exploration into other armor steels and impact conditions is recommended to assess the method's versatility.展开更多
A modified one-dimensional transient hygrothermal model for multilayer wall was proposed using air humidity ratio and temperature as the driving potentials.The solution for the governing equations was obtained numeric...A modified one-dimensional transient hygrothermal model for multilayer wall was proposed using air humidity ratio and temperature as the driving potentials.The solution for the governing equations was obtained numerically by implementing the finite-difference scheme.To evaluate the accuracy of the model,a test system was built up to measure relative humidity and temperature within a porous wall and compare with the prediction of the model.The prediction results have good agreement with the experimental results.For the interface close to indoor side,the maximum deviation of temperature between calculated and test data is 1.87 K,and the average deviation is 0.95 K;the maximum deviation of relative humidity is 11.4%,and the average deviation is 5.7%.For the interface close to outdoor side,the maximum deviation of temperature between prediction and measurement is 1.78 K,and the average deviation is 1.1 K;the maximum deviation of relative humidity is 9.9%,and the average deviation is 4.2%.展开更多
To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dime...To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried out.Various test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of rail.Combining the simulation results and experimental data,the damage condition of the contact surface is analyzed.展开更多
大语言模型(large language model,LLM)在一般性教学辅助、文科课程和计算机课程中得到成功应用,但应用于电力电子实验教学时存在电路拓扑图识别不准、关键信息缺失等问题。为此,该文提出基于智能插件和LLM的教学辅助设计方法:首先通过...大语言模型(large language model,LLM)在一般性教学辅助、文科课程和计算机课程中得到成功应用,但应用于电力电子实验教学时存在电路拓扑图识别不准、关键信息缺失等问题。为此,该文提出基于智能插件和LLM的教学辅助设计方法:首先通过深度学习模型实现电路拓扑图识别,并将其转换为电路网表文本;然后向LLM提供网表文本及不同提示词,引导LLM实现网表检查、电路分析、文档生成、知识问答等教学功能,为教师提供高质量的教学设计起点。该方法有望减轻教师负担,提高实验教学的时效性和教学质量,为电力电子实验教学设计提供一种有用工具。展开更多
运用建筑信息模型(Building Information Modeling,BIM)技术,以北魏宣武帝景陵遗址为对象进行虚拟建构实验教学。针对外业信息采集、内业数据处理、建筑内部病害标记与汇总、BIM模型建构与虚拟修缮4个模块开展对学生仪器使用、数据处理...运用建筑信息模型(Building Information Modeling,BIM)技术,以北魏宣武帝景陵遗址为对象进行虚拟建构实验教学。针对外业信息采集、内业数据处理、建筑内部病害标记与汇总、BIM模型建构与虚拟修缮4个模块开展对学生仪器使用、数据处理、建筑病害整理和BIM建模方法等方面的对应训练。教学实践表明,结合建筑遗产实际项目的实验教学能够有效保障学生对于相关技术的理解与掌握,锻炼设备操作与课题研究能力,锤炼专业技能的同时进一步提升遗产保护意识、开拓遗产保护视野。展开更多
基金supported by the Ministry of Science,Technological Development and Innovation of the Republic of Serbia,through the Contract no.451-03-65/2024-03/200105
文摘This paper proposes a modification of the Forrestal-Warren perforation model aimed at extending its applicability range to intermediately-thick high-hardness armor steel plates.When impacted by armorpiercing projectiles,these plates tend to fail through adiabatic shear plugging which significantly reduces their ballistic resistance.To address this effect,an approach for determining effective thickness was defined and incorporated into the predictive model.Ballistic impact tests were performed to assess the modification's validity,in which ARMOX 500T steel plates were subjected to perpendicular impacts from 7.62×39 mm steel-cored rounds under various velocities.Frequent target failure by soft plugging was observed,as well as the brittle shatter of the hard steel core.Key properties of the recovered plugs including their mass,length and diameter were measured and reported along with the projectiles'residual velocities.Additionally,independent data from the open literature were included in the analysis for further validation.The original Forrestal-Warren model and the novel effective thickness modification were then used to establish the relationship between impact and residual velocities,as well as to determine the ballistic limit velocity.The comparison revealed that the proposed approach significantly improves the model's accuracy,showing a strong correlation with experimental data and reducing deviations to within a few percent.This enhancement highlights the potential of the effective thickness term,which could also be applied to other predictive models to extend their applicability range.Further exploration into other armor steels and impact conditions is recommended to assess the method's versatility.
基金Project(51078127) supported by the National Natural Science Foundation of ChinaProject(JJ201109091631) supported by the Foundation for Young Scientists of Jiangxi Education Department, China
文摘A modified one-dimensional transient hygrothermal model for multilayer wall was proposed using air humidity ratio and temperature as the driving potentials.The solution for the governing equations was obtained numerically by implementing the finite-difference scheme.To evaluate the accuracy of the model,a test system was built up to measure relative humidity and temperature within a porous wall and compare with the prediction of the model.The prediction results have good agreement with the experimental results.For the interface close to indoor side,the maximum deviation of temperature between calculated and test data is 1.87 K,and the average deviation is 0.95 K;the maximum deviation of relative humidity is 11.4%,and the average deviation is 5.7%.For the interface close to outdoor side,the maximum deviation of temperature between prediction and measurement is 1.78 K,and the average deviation is 1.1 K;the maximum deviation of relative humidity is 9.9%,and the average deviation is 4.2%.
文摘To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried out.Various test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of rail.Combining the simulation results and experimental data,the damage condition of the contact surface is analyzed.
文摘大语言模型(large language model,LLM)在一般性教学辅助、文科课程和计算机课程中得到成功应用,但应用于电力电子实验教学时存在电路拓扑图识别不准、关键信息缺失等问题。为此,该文提出基于智能插件和LLM的教学辅助设计方法:首先通过深度学习模型实现电路拓扑图识别,并将其转换为电路网表文本;然后向LLM提供网表文本及不同提示词,引导LLM实现网表检查、电路分析、文档生成、知识问答等教学功能,为教师提供高质量的教学设计起点。该方法有望减轻教师负担,提高实验教学的时效性和教学质量,为电力电子实验教学设计提供一种有用工具。
文摘运用建筑信息模型(Building Information Modeling,BIM)技术,以北魏宣武帝景陵遗址为对象进行虚拟建构实验教学。针对外业信息采集、内业数据处理、建筑内部病害标记与汇总、BIM模型建构与虚拟修缮4个模块开展对学生仪器使用、数据处理、建筑病害整理和BIM建模方法等方面的对应训练。教学实践表明,结合建筑遗产实际项目的实验教学能够有效保障学生对于相关技术的理解与掌握,锻炼设备操作与课题研究能力,锤炼专业技能的同时进一步提升遗产保护意识、开拓遗产保护视野。
