爆炸焊接参数设计能量模型(Ⅰ)

论述了建立爆炸焊接参数设计能量模型的依据和方法，得到了表征能级分布和能级转换的等能量线和数学表达式，阐明了焊接参数的变化规律和等能量线的性质。     

爆炸焊接参数设计能量模型(Ⅱ)

用等能量线和能级转换轨迹线建立了新的焊接参数上下限边界 ,结合能量方程 ,为建立可焊性窗口和优化参数设计提供了可靠依据     

高含铝炸药爆炸过程中的能量分析

在野外静爆实验中,利用高分辨率、高精度冲击波超压系统分别测试了高含铝炸药和TNT的爆炸场冲击波超压,根据试验数据,计算该含铝炸药的爆炸场冲击波超压的TNT当量,利用TNT当量评价该高含铝炸药的威力,用能量反演方法分析该含铝炸药中可燃组分的反应程度和可能的反应模式,计算可得该含铝炸药爆炸反应释放能量的有效利用率为65.41％,为高含铝炸药配方优化设计提供新的研究方法.     

建筑管道自然通风中的能量转换

本文应用伯努利方程以及流体力学的基本原理,通过对自然通风管道内外气体能量转换过程进行研究,为解决建筑管道自然通风长期存在的问题提供一种新的思路,供建筑界同仁参考.     

双金属爆炸焊接参数设计理论

针对爆炸焊接参数设计问题,从爆炸焊接基本理论出发,分步介绍了飞板爆轰驱动的理论和双金属爆炸焊接窗口理论。首先归纳总结了一维爆轰驱动飞板的终速公式,并详细说明了其应用范围与原因。对于二维滑移爆轰驱动飞板问题,主要针对Richter理论和特征线法进行了介绍,并推导出新的近似计算公式。接着,对于爆炸焊接参数窗口理论,详细比较了以往传统单一金属爆炸焊接窗口理论与公式,并针对部分已有公式进行了重新推导与修正,重新界定了其适用范围。利用这些爆炸焊接窗口的基本理论,作者对所发展的双金属可焊下限、双金属可焊上限、双金属流动限以及声速限构成的双金属爆炸焊接窗口理论进行了系统地介绍。最后,以飞板爆轰驱动和爆炸焊接窗口构建成了整个爆炸焊接工艺技术参数设计理论,并结合二元合金相图进行爆炸焊接设计,针对调控原材料硬度的必要性、焊接界面波纹及气孔的控制方法等问题进行了讨论。     

爆炸焊接最佳药量窗口及其参数的确定

介绍了最佳药量窗口的设想,结合爆速试验结果,推导出了起爆端最小装药厚度计算公式。依据不等厚度布药工艺,给出了爆轰末端装药厚度的计算原则。根据＂结合界面不产生过熔＂的原则,提出了下临界复板厚度的确定公式,由此完善了最佳药量窗口各参数的计算方法。实践表明最佳药量窗口具有一定的实用价值。     

爆炸压实工艺参数对钢管能量与变形的影响

为了指导研究爆炸压实工艺参数的选择,通过改变爆轰速度与装药厚度来改变爆炸冲击能,重点研究爆炸压实工艺参数对钢管能量与变形的影响.研究表明:当其他工艺因素相同、仅爆轰速度不同时,将导致爆轰压力、钢管壁速度、爆炸冲击能、粉末压实能等显著不同,但钢管的变形与能量却几乎不变;当采用爆轰速度极高的黑索今炸药时,由于爆轰压力与爆炸冲击能过高,导致钢管头部被切掉;对硝酸脲炸药而言,随着装药厚度与炸药/钢管质量比增加,钢管的能量与变形、爆炸冲击能与粉末压实能单调增加.     

基于能量法的缓冲器参数设计

通过建立起落架的运动模型及数学模型,在进行了全面的运动分析和受力分析的基础上,经过计算初步确定了缓冲器的性能参数,然后用能量法对缓冲器的参数进行了核验计算。最后通过摇臂式起落架参数的设计计算对计算过程进行了验证。     

基于遗传算法与能量方程的粘弹性隔震装置参数优化分析

本文基于能量方程研究了粘弹性隔震装置的参数优化问题,从能量角度提出了基于遗传算法的目标优化函数,建立了粘弹性隔震装置参数优化模型。以柱面网壳隔减震为例,基于遗传算法和能量方程,采用ANSYS和MATLAB并行对其进行参数优化分析,并分析了该方法对地震波的敏感性。结果表明：基于能量方程的优化目标函数,通过遗传算法优化分析得到的粘弹性隔震参数能够使得结构的位移和应力得到有效的控制;同时也表明该优化方法受不同地震波的影响较小。     

爆炸法密实砂土地基(Ⅳ)——设计方法

沿处理深度方向上装药量、装药形式、装药深度是爆炸法密实饱和砂地基设计中比较敏感的设计参数,且决定了炸药爆炸释放能量在处理土体中分布均匀的程度。三者之间对处理效果是相互联系、相互影响的,目前尚无统一量化的指标将三者联系起来、定量分析上述三个指标对处理效果影响的方法和评价标准。本文首先应用了Narin van court(1997)〔1〕提出的E1函数,将模型试验中装药形式、药包重量、药包埋设深度三个比较敏感的设计参数统一量化,分析了输入能量E1与处理效果的关系;基于爆炸输入能量E1在加固处理土体中的分布,提出了能量分布评价函数,定量地分析爆炸输入能量在处理土体中分布的均匀程度,并将能量分布评价值作为优化爆炸法密实砂土地基设计方法的参数,最后探讨了基于能量分布的设计方法及流程。     

Process configuration of Liquid-nitrogen Energy Storage System (LESS) for maximum turnaround efficiency

Diverse power generation sector requires energy storage due to penetration of variable renewable energy sources and use of CO₂ capture plants with fossil fuel based power plants. Cryogenic energy storage being large-scale, decoupled system with capability of producing large power in the range of MWs is one of the options. The drawback of these systems is low turnaround efficiencies due to liquefaction processes being highly energy intensive. In this paper, the scopes of improving the turnaround efficiency of such a plant based on liquid Nitrogen were identified and some of them were addressed. A method using multiple stages of reheat and expansion was proposed for improved turnaround efficiency from 22% to 47% using four such stages in the cycle. The novelty here is the application of reheating in a cryogenic system and utilization of waste heat for that purpose. Based on the study, process conditions for a laboratory-scale setup were determined and presented here.     

两险种广义Erlang（2）风险模型的破产概率

本文考虑一类具有两个独立险种的风险模型的破产概率,假设该模型的两个索赔计数过程是独立的两个广义Erlang(2)过程。利用微分分析和矩阵表示,得到破产概率满足的一个积分-微分方程组及其边界条件。在索赔计数过程是普通Erlang(2)过程的情形下,证明了广义Lundberg方程有且仅有三个正的实数根,由此并结合破产概率满足的积分-微分方程组,给出了破产概率的Laplace变换。     

连接不相交线段成简单多边形(链)的算法

提出一个实际问题，即如何连接平面上h条线段成一简单多边形或者简单多边形链，并证明了连接平面上线段集S成一简单多边形链的一个充分条件，S中有一条线段连接凸壳CH（S）中不相邻顶点，另外还提出了连接平面上线段集S成一简单多边形或者简单多边形链的算法，其基本思想是首先逐层计算线段集S的凸壳，并将这些凸壳改变多边形；然后计算各多边形之间的交点，进而删去这些交点。最后合并若干个简单多边形为一个简单多边形，当S中线段数目n较大时，用分治思想可以设计分治算法，较好地求解了这个问题，利用计算机求解这个问题上有实际应用价值。     

An Equation of State for 1,1,1-Trifluoroethane (R-143a)

A fundamental equation of state has been developed for 1,1,1-trifluoroethane (R-143a) using the dimensionless Helmholtz energy. The experimental thermodynamic property data, which cover temperatures from the triple point (161 K) to 433 K and pressures up to 35 MPa, are used to develop the present equation. These data are represented by the present equation within their reported experimental uncertainties: ±0.1% in density for both vapor and liquid phase P––T data, ±1% in isochoric specific heat capacities, and ±0.02% in the vapor phase speed-of-sound data. The extended range of validity of the present model covers temperatures from 160 to 650 K and pressures up to 50 MPa as verified by the thermodynamic behavior of the isobaric heat-capacity values over the entire fluid phase.     

An equation of state for 1,1-difluroethane (HFC 152a)

An equation of state for 1,1-difluoroethane (HFC 152a, CH₃CHF₂) has been developed on the basis of reliable experimental data including PVT, liquid C_p, and saturated-liquid-density data measured by our group. It is a non-dimensionalized virial equation whose functional form is the same as that originally developed for 1,1,1,2-tetrafluoroethane (HFC 134a) in our group. The effective range is for pressures up to 15 MPa, temperatures from 230 to 450 K, and densities to 1000 kg m⁻³. The equation represents reliable PVT measurements within ± 1% in pressure for the superheated vapour and supercritical fluid, while within ±0.5% in density for the compressed liquid. In addition, it should be noted that the equation represents the other essential thermodynamic properties including vapour pressures, saturated-liquid/ vapour densities, isobaric/isochoric specific heats and sound velocity in both the liquid and gaseous phase of HFC 152a.     

基于热力学理论的Fe-Mn-Al-C系低密度钢层错能计算模型

本研究详细分析了基于热力学相关理论建立的层错能(SFE)计算模型和测定层错能的实验方法,将基于Olson-Cohen热力学理论模型计算的Fe-Mn-Al-C低密度高强钢的层错能结果与若干文献中的实测值进行了比较,验证了Olson-Cohen热力学理论模型的可靠性,并回溯和修正了模型中各主要参数。使用层错能模型对Fe-(10~30)Mn-(0~12)Al-(0~1.2)C(质量分数/%)系低密度钢进行计算,结果表明,Mn、Al、C含量的增加均会使低密度钢的层错能增加,但层错能对Al元素最敏感,各元素对层错能的影响能力为γSFE,AlγSFE,MnγSFE,C。此外,温度升高会使层错能增加,且高温区间(300~1 000K)相比低温区间(0~300K)层错能增加更快。     

A Rigorous Thermodynamic Property Model for Fluid-Phase 1,1-Difluoroethane (R-152a)

A new thermodynamic property model for the Helmholtz free energy with rational third virial coefficients for fluid-phase 1,1-difluoroethane (R-152a) was developed. The model was validated by existing experimental data for temperatures from the triple point to 450 K and pressures up to 60 MPa. Reasonable behavior of the second and third virial coefficients was confirmed from intermolecular potential models. The estimated uncertainties are 0.1% in density for the gaseous and liquid phases, 0.4% in density for the supercritical region, 0.05% in speed of sound for the gaseous phase, 2% in speed of sound for the liquid phase, and 1% in specific heat capacities for the liquid phase. From the reasonable behavior of the ideal curves and the third virial coefficients, the model can be assumed reliable in representing the thermodynamic properties not only at states with available experimental data but also at states for which no experimental data are available.     

Lattice Discrete Particle Model (LDPM) for failure behavior of concrete. I: Theory

This paper deals with the formulation, calibration, and validation of the Lattice Discrete Particle Model (LDPM) suitable for the simulation of the failure behavior of concrete. LDPM simulates concrete at the meso-scale considered to be the length scale of coarse aggregate pieces. LDPM is formulated in the framework of discrete models for which the unknown displacement field is not continuous but only defined at a finite number of points representing the center of aggregate particles. Size and distribution of the particles are obtained according to the actual aggregate size distribution of concrete. Discrete compatibility and equilibrium equations are used to formulate the governing equations of the LDPM computational framework. Particle contact behavior represents the mechanical interaction among adjacent aggregate particles through the embedding mortar. Such interaction is governed by meso-scale constitutive equations simulating meso-scale tensile fracturing with strain-softening, cohesive and frictional shearing, and nonlinear compressive behavior with strain-hardening. The present, Part I, of this two-part study deals with model formulation leaving model calibration and validation to the subsequent Part II.