方形中空夹层钢管超高性能钢纤维混凝土柱抗爆性能数值模拟与实验验证

建立了爆炸荷载作用下方形中空夹层钢管超高性能钢纤维混凝土(Ultra-High Performance Steel Fiber Reinforced Concrete Filled Double Skin Steel Tube,UHPSFRCFDST)柱动态响应及其损伤破坏三维有限元数值模型。首先通过模拟结果与爆炸破坏试验结果的对比分析,验证了数值模型和计算方法的有效性。进而运用参数化分析方法,研究了空心率、含钢率、内、外层钢管厚度及其强度等关键参数对UHPSFRCFDST柱抗爆性能的影响。研究结果表明,UHPSFRCFDST柱具有优越的抗爆性能,所建立的三维有限元模型能够有效地分析UHPSFRCFDST柱在爆炸荷载作用下的动态响应及其损伤破坏;在一定范围内减小空心率及提高外层钢管强度可有效提升UHPSFRCFDST柱抗爆性能;提高含钢率、减小内、外层钢管高厚比均能够显著提升UHPSFRCDST柱抗爆性能;内层钢管强度对UHPSFRCFDST柱的抗爆性能影响并不明显。     

在动载作用下衬砌洞室抗爆加固效果数值分析

利用数值分析软件LS-DYNA3D程序,研究了在爆炸荷载作用下衬砌加固洞室的抗爆加固效果以及衬砌参数对抗爆加固效果的影响规律。通过分析毛洞和衬砌洞室拱顶同一位置的压力曲线,得出压应力波形及传播规律合理;经过衬砌加固的洞室拱顶峰值位移明显减少,抗爆加固效果显著;当弹性模量不大时,随着弹性模量的增大,抗爆加固效果有所提高,但当弹性模量增大到一定值时,再增加衬砌的弹性模量,其抗爆加固效果反而不佳;衬砌的厚度对洞室的抗爆加固效果有一定的影响,但当衬砌的厚度增加到一定值时,再增加其厚度并不能明显提高衬砌洞室的抗爆加固效果。     

地表爆炸荷载作用下大型输水箱涵的毁伤评估及防护效应分析

随着我国跨区域调水工程的增多,箱涵结构的抗爆问题越来越受到重视。考虑爆炸荷载作用下混凝土的应变率效应、流体与固体间的耦合以及结构的非线性动态响应等复杂问题,基于Lagrangian-Eulerian耦合方法建了地表爆炸荷载作用下钢筋混凝土输水箱涵的全耦合模型。通过与已有的经验公式和现场爆炸试验进行对比,分别验证了土体地表爆炸模型和爆炸荷载作用下钢筋混凝土模型的可靠性;对比研究了有水和无水两种工况下箱涵的动力响应及毁伤发展过程,并分析了地表爆炸荷载作用下冲击波的传播特性;同时采用聚苯乙烯泡沫作为箱涵的防护材料,探讨了其对钢筋混凝土输水箱涵抗爆性能的影响。结果表明:突发地表爆炸荷载将对输水箱涵结构的安全性构成巨大的威胁;而在箱涵顶部铺设聚苯乙烯泡沫可以有效地提高其抗爆性能。     

含泡沫铝防护层隧道衬砌结构的抗爆性能研究

隧道内爆炸作用可能导致其衬砌结构的破坏和坍塌,造成车辆通行受阻和生命财产损失。本文利用AUTODXN软件对含泡沫铝防护层隧道衬砌结构的抗爆性能进行数值模拟,分析了不同厚度防护层的抗爆效果。结果表明：泡沫铝对爆炸冲击波有良好的吸能作用和衰减特性,对隧道衬砌的损伤有明显的防护效果。     

链枷式排爆装置抗爆性能的仿真与试验研究

为了探究链枷式排爆装置的抗爆性能是否满足作业需求,以ANSYS软件为技术平台,建立了该排爆装置抗爆性能的仿真计算模型。依托该模型,对不同TNT当量、不同爆炸位置等多种工况下排爆装置的抗爆性能进行了分析,得到其结构变形量和速度特性。同时,搭建了链枷式排爆装置的抗爆性能试验台架,通过台架试验验证了仿真模型的可信性,为排爆装置抗爆性能分析评价与结构优化设计提供参考。     

固支圆形泡沫铝夹芯板在爆炸作用下变形研究

为研究泡沫铝夹芯板(简称"AFSP")的抗爆特性及其与泡沫铝板或实体金属板抗爆性能差异,对3种固支圆形板在钢管内油气混合物点火产生的爆炸荷载作用下残余变形进行试验研究。主要分析泡沫铝板在爆炸荷载下破坏特点、相同荷载条件下AFSP与实体金属板残余变形大小差异、面板材质与芯材厚度的变化对AFSP残余变形的影响等。试验结果显示:单独泡沫铝板在爆炸荷载作用下易发生整体剪切破坏;与实体板相比,芯材厚度为16 mm的AFSP在质量仅增加25.9%的条件下,残余变形减小48.5%;同载同重的钢面板较不锈钢面板AFSP的残余变形量减小30.7%;AFSP的芯材厚度由8 mm增加至16 mm,在荷载稍有增加时,残余变形反而减少了51.6%。AFSP较相同重量的实体金属板具有更好抵抗爆炸荷载的能力,AFSP的芯材厚度与面板材料是影响其抗爆性能的两个重要因素,AFSP是一种具有较好抗爆性能的复合材料。     

POZD涂覆钢板加固钢筋混凝土板抗爆性能研究

为了研究聚异氰氨酸酯噁唑烷(Polyisocyanate oxazodone, POZD)聚合物高分子材料涂覆钢板-钢筋混凝土板在接触爆炸荷载作用下的抗爆性能,开展了接触爆炸试验和数值模拟研究,对其破坏特征进行分析。采用有限元软件LS-DYNA建立了钢筋混凝土板、炸药、钢板和POZD的有限元模型,讨论了不同药量下POZD涂覆钢板加固钢筋混凝土板的破坏模式和破坏特征。试验及数值结果表明：在钢板-钢筋混凝土板背面涂覆POZD涂层能有效提升结构的抗爆性能;在接触爆炸作用下,POZD涂覆钢板加固钢筋混凝土板试件呈现四种破坏模式。     

高强钢丝绳网片-聚合物砂浆加固RC板抗爆性能试验研究

为了研究高强钢丝绳网片-聚合物砂浆对钢筋混凝土(RC)板的抗爆加固效果,对5块加固RC板和1块未加固RC板进行了野外现场爆炸试验,研究了砂浆强度、钢丝绳间距、钢丝绳预应力和界面增设销钉等因素对试件的破坏形态、裂缝分布及发展、跨中位移、钢筋应变等影响规律,并对爆炸试验后的试件进行了剩余承载力试验和爆炸损伤评估。研究表明:高强钢丝绳网片-聚合物砂浆加固能显著提高RC板的抗爆性能,相比于未加固板,加固板的裂缝宽度,板底跨中的峰值位移、残余位移和钢筋应变均大幅减小;加固后,构件剩余承载力大幅增加,其损伤程度大为降低。     

重力坝水下接触爆炸的数值分析

采用显式程序AUTODYN中的Euler-Lagrange耦合算法模拟混凝土重力坝水下接触爆炸。研究在不同炸点的水下接触爆炸荷载作用下大坝的动力响应以及损伤裂纹分布特点。针对上述特点采用泡沫铝作为抗爆材料,研究了泡沫铝的抗爆效果。研究结果表明:采用泡沫铝作为大坝水下爆炸抗爆材料能大幅降低爆炸冲击波幅值,减小大坝的动力响应,同时能减小爆炸对坝体产生损伤及裂纹分布范围,具有良好的抗爆性能。     

爆炸作用下高强钢绞线网片-聚合物砂浆加固钢筋混凝土板的数值模拟

为了探究高强钢绞线-聚合物砂浆加固技术对钢筋混凝土板的抗爆性能的影响,应用有限元分析软件ANSYS/LS-DYNA对其进行了在爆炸荷载作用下的数值模拟。在验证有限元模型合理性的基础上,对比分析了爆炸荷载作用下砂浆层厚度、砂浆强度和钢绞线直径等不同加固参数对钢筋混凝土板的破坏形态与板底位移的影响。结果表明:采用高强钢绞线-聚合物砂浆加固后钢筋混凝土板的抗爆性能显著提高;在砂浆加固层厚度、砂浆强度、钢绞线直径3种加固影响参数中,砂浆加固层厚度对钢筋混凝土板的加固效果影响显著,而砂浆强度和钢绞线直径对板的加固效果不明显。如果运用该技术提高钢筋混凝土板的抗爆性能,优先考虑增大加固层厚度。     

Experimental Investigation on Turning of Double Metal Composite with Network Interpenetrating Structure

The interpenetrating double metal phase composite is anisotropic. According to the structural and mechanical properties, the cutting process becomes more complicated. In this work, experimental investigation was systematically studied by means of turning experiments, and focused on cutting force and surface roughness; extra attention has been paid to the cutting phenomena in the zone of reinforcing phase and bimetal interface. Cutting force performance is similar to the ordinary materials, but there are several impact forces in cutting process. In addition, it is easy to produce cracks and exfoliations at metal/metal interface. These phenomena will lead to the decline of the machined surface quality.     

Progress in cold roll bonding of metals

Abstract

Layered composite materials have become an increasingly interesting topic in industrial development. Cold roll bonding (CRB), as a solid phase method of bonding same or different metals by rolling at room temperature, has been widely used in manufacturing large layered composite sheets and foils. In this paper, we provide a brief overview of a technology using layered composite materials produced by CRB and discuss the suitability of this technology in the fabrication of layered composite materials. The effects of process parameters on bonding, mainly including process and surface preparation conditions, have been analyzed. Bonding between two sheets can be realized when deformation reduction reaches a threshold value. However, it is essential to remove surface contamination layers to produce a satisfactory bond in CRB. It has been suggested that the degreasing and then scratch brushing of surfaces create a strong bonding between the layers. Bonding mechanisms, in which the film theory is expressed as the major mechanism in CRB, as well as bonding theoretical models, have also been reviewed. It has also been showed that it is easy for bcc structure metals to bond compared with fcc and hcp structure metals. In addition, hardness on bonding same metals plays an important part in CRB. Applications of composites produced by CRB in industrial fields are briefly reviewed and possible developments of CRB in the future are also described.     

三基发射药单螺杆压伸模具流场仿真及实验验证

为了实现三基发射药生产工艺中的连续化压伸,同时避免模具内部螺旋状流道造成的三基发射药成型的质量和安全问题,应用ANSYS软件模拟了发射药物料在模具内的挤压过程及模针的受力情况。分析了收缩角、出料方向和模具结构对物料在模具中的温度、模具壁面压力、模针表面受力和物料出料速度分布的影响规律,并通过实验进行了验证。结果表明:模具收缩角越大,模具内压力越大,物料温度也越高,且越容易形成热点,同时模针外表面受到的挤压力和摩擦力也越大,模针越容易出现变形和断裂;竖直挤出过程中,模具壁面压力及模针受力均远大于水平挤出中的相应参数,且容易造成挤出后物料的弯曲;增加多孔板有利于物料在挤出模具中的整流和取向,大幅减少物料的径向流动,降低模针在挤出过程中的受力,且成型质量更好。     

Bio-inspired study of structural materials

The terminology of materials study inspired by biological systems or phenomena is analyzed at first. It is pointed that the term “bio-inspired” may be better than the terms “bionic” or “biomimetic”, since the former is relatively easy to be accepted. The new trends of bio-inspired study of structural materials are analyzed in short. Some progress in bio-inspired design and processing of materials in this institute (IMRCAS) are summarized briefly in this talk, such as biomimetic design of worst bonding interface for composites; dumbell-like whiskers simulating animal bone; fractal tree reinforcement by mimicry of branched roots in soil; etc.The possibility of modification and recovery of materials by nonequilibrium bio-inspired treatment are further explored, including the nonequilibrium process under transient heating, dissipative structure and self-organization process of open system, inspiration by living process, influence of high intensive electropulsing on the working life of materials, a possible way of fatigue recovery of materials and the healing effect of electropulsing in metals. Some tentative practice in biomaterial modification are also studied such as the reformed bamboo reinforced aluminium laminates, etc. A discussion on the methodology of bio-inspired study of materials consists briefly in the last part of the talk.     

Flexible replication technique for high-aspect-ratio nanostructures

A flexible, nondestructive, and cost-effective replication technique for nanostructures is presented. The advantages of the process are: 1) it allows for tailoring structural parameters of the replica (e.g., line width) nearly independent of the structural geometry of the master; 2) it allows for replication of high-aspect-ratio structures also in polymer materials from solution (especially noncurable polymers) such as polystyrene and polymethylmethacrylate; 3) it includes an easy separation process, thus preserving the master for repeated use. Linear grating replicas with line widths ranging from 88 to 300 nm are obtained using a single nanostructured master. Nanofibers and complex nanopatterned replicas are achievable. The presented technique and its flexibility show that atomic layer deposition is a unique tool for the preparation of high-efficiency polarizer diffractive optics, photonics, electronics, and catalysts.     

Optimization of Microporous Carbon Structures for Lithium–Sulfur Battery Applications in Carbonate‐Based Electrolyte

Developing appropriate sulfur cathode materials in carbonate‐based electrolyte is an important research subject for lithium‐sulfur batteries. Although several microporous carbon materials as host for sulfur reveal the effect, methods for producing microporous carbon are neither easy nor well controllable. Moreover, due to the complexity and limitation of microporous carbon in their fabrication process, there has been rare investigation of influence on electrochemical behavior in the carbonate‐based electrolyte for lithium‐sulfur batteries by tuning different micropore size(0–2 nm) of carbon host. Here, we demonstrate an immediate carbonization process, self‐activation strategy, which can produce microporous carbon for a sulfur host from alkali‐complexes. Besides, by changing different alkali‐ion in the previous complex, the obtained microporous carbon exhibits a major portion of ultramicropore (<0.7 nm, from 54.9% to 25.8%) and it is demonstrated that the micropore structure of the host material plays a vital role in confining sulfur molecule. When evaluated as cathode materials in a carbonate‐based electrolyte for Li‐S batteries, such microporous carbon/sulfur composite can provide high reversible capacity, cycling stability and good rate capability.     

Mass production of multi-wall carbon nanotubes by metal dusting process with high yield

Carbon nanotube materials were synthesized over Fe-Ni nanoparticles generated during disintegration of the surface of alloy 304L under metal dusting environment. The metal dusting condition was simulated and optimized through exposing stainless steel samples during long term repetitive thermal cycling in CO/H₂ = 1/1, total gas flow rate 100 cm³/min, at 620 °C for 300 h. After reaction, surface morphology of the samples and also carbonaceous deposition which had grown on sample surfaces were examined by stereoscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results revealed that multi-wall carbon nanotubes could be formed over nanocatalyst generated on the alloy surface by exploiting metal dusting process. By optimization of reaction parameters the yields of carbon nanotube materials obtained were 700-1000%. Also it has been shown herein that the amount of carbon nanotube materials remarkably increases when the reaction time is extended up to 300 h, indicating a possibility of the mass production by this easy method.     

组合式半轴法兰摆辗模具设计

就半轴法兰摆辗模具中存在的问题,对原摆辗模具进行了改进设计,并对模具材料进行了改进,使模具适合在冲击载荷很大的环境下使用。对改进的模具结构和模具材料进行了实际生产验证,表明改进后的模具凸模更换方便,易于操作,在模具需要返修或者报废时,减少模具更换模块,模具返修次数减少,而且易于加工,降低了模具成本。     

A "paint-on" protocol for the facile assembly of uniform microgel coatings for color tunable etalon fabrication

Robust, uniform, monolithic microgel thin films can be created by actively spreading a concentrated solution of microgels onto a Au surface at 30 °C. The method is easy, fast, and seemingly universal: it can be used to coat a variety of Au coated surfaces with microgels containing different chemical functionalities. No control of the deposition conditions, other than temperature and microgel concentration, is required. We show that this technique consistently produces monolithic microgel films on Au-coated surfaces, and it has been extended to coat Si substrates. After deposition of a thin Au overlayer onto the deposited microgel layer, the materials are colored, as evidenced by multiple peaks in their reflectance spectra. The assemblies deposited using the described "paint-on" technique show increased spectral and visual purity over the entire surface area as compared to colored materials made by a previously used passive drying process.     

‘Soft solution processing’in situ fabrication of morphology-controlled advanced ceramic materials in low temperature solutions without firing

A process called ‘soft solution processing’ has been introduced to fabricate advanced solid state materials in an economical, environmental friendly, and energy and material efficient way. A concise discussion of how to improve the synthetic conditions and how to extend the applied system is given. The successful examples show that soft solution processing is capable of preparing advanced materials with planned properties through the easy control of reaction conditions in a suitable aqueous solution in a single synthetic step without huge energy consumption for sintering or melting and without any sophisticated equipment.