新型地质力学模型材料(MIB)

研制高容重、低弹模、低强度模型材料是地质力学模型试验的一个重要课题,本文分析了以往国内外有关该课题的研究成果,提出研制这种材料的若干新见解和原则,并介绍了所研制出的一种适用于地质力学模型试验的新型材料,取名为MIB材料。     

大型窑洞式地下厂房围岩稳定性试验分析

本试验利用自制的地质力学模型材料(MSB),在窑洞式地下厂房的立式平面应力模型的周边上,按实际主应力方向进行加载。成功地模拟了原始地应力场,得出了洞室在实际开挖过程中围岩应力变化、洞室变形状况及破坏形态。     

SBR-水性环氧-脱色乳化沥青复合胶结料性能研究

为提升脱色乳化沥青的柔韧性和黏附性,探究SBR-水性环氧-脱色乳化沥青复合胶结料的最佳配比,在室内制备了不同配比的SBR-水性环氧-脱色乳化沥青复合胶结料,并采用拉拔试验、拉伸试验、低温韧性试验、荧光显微镜试验等方法,对复合胶结料的黏附性、强度、低温抗裂性等进行了测试。研究结果表明：水性环氧树脂掺量为50%、SBR掺量为4%时,复合胶结料的强度和柔韧性显著提升;水性环氧树脂的掺量为50%、SBR的掺量小于5%范围内,SBR-水性环氧-脱色乳化沥青复合胶结料具有稳定的交联结构体系且稳定性最好;水性环氧树脂掺量不超过40%,其低温抗裂性最好;推荐水性环氧树脂掺量为50%、SBR掺量为4%时为SBR-水性环氧-脱色乳化沥青复合胶结料最佳配比。     

地下洞群围岩稳定的试验研究

本文采用模型试验的方法．研究地下洞群围岩稳定的问题．模型使用一种特制的新型地质力学模型材料，它基本上满足模型与原型全相似的要求．由于采用这种材料，使得模型加载装置得以轻型化．试验通过平面应变和三维两种破坏模型进行．平面应变模型为立式的．试验成果与相应计算成果很相接近．     

岩体相似材料的研究

在新型地质力学模型材料的基础上，对该项材料的特征，相关参数，配比组合，胶结剂性能，成型工艺以及物理力学性能等作了进一步的深入研究，改善了某些不足之处，并根据大量的试验数据绘制了综合特性曲线，使有关材料和参烽的选择达到系列化、规范化，扩大了该项材料的适用范围。     

岩体相似材料的研究

在新型地质力学模型材料（ＭＩＢ）的基础上，对该项材料的特征、相关参数、配比组合、胶结剂性能、成型工艺以及物理力学性能等作了进一步的深入研究，改善了某些不足之处，并根据大量的试验数据绘制了综合特性曲线，使有关材料和参数的选择达到系列化、规范化．扩大了该项材料的适用范围     

复杂岩基上重力坝坝基稳定模型试验与有限元分析

软弱结构面发育、断层与错动带相互交错是复杂岩基的重要特征。针对武都重力坝地质条件极其复杂的特点,试验研制出适合该工程地质条件的模型材料,建立了典型坝段坝基的地质力学试验模型和3维非线性有限元计算模型。采用地质力学模型综合法试验和3维非弹性有限元计算方法研究武都重力坝加固方案的坝基稳定问题,两种方法得出16^#-19^#坝段的综合安全系数Kc分别为3.6-4.8和3.8-5.4,两种研究方法的结果基本一致。同时,试验和计算研究成果表明,坝基加固处理后,坝与地基的变形明显减小,稳定安全系数显著提高,为坝基抗滑稳定安全性评价和加固设计提供了科学依据。将试验与计算紧密结合起来进行复杂岩基上重力坝的坝基稳定分析为其他类似工程提供了参考。     

胶结充填材料的强度特性与强度设计(Ⅰ)——胶结充填体的强度设计

目前国内外胶结充填体强度的设计方法可分为三类,即类比法、模型法及数值分析法。本文对国内外部分矿山胶结充填体的强度设计方法及主要参数进行了归纳和分析,并采用模型法按照胶结充填体的高度与强度这一对矛盾因素,得出了一条强度经验曲线和计算公式。文中还介绍了胶结充填料强度测试的基本方法。     

基于正交试验的汉堡轮辙深度影响因素分析

汉堡轮辙试验是目前用于评价沥青混合料水稳定性及高温稳定性最为苛刻的试验方法之一,其评价指标主要有轮辙变形深度、蠕变线、剥落线、剥落拐点。文章以沥青胶结料的135℃旋转黏度、试验次数、试验温度及试件孔隙率四个因素作为控制因素,通过正交试验,对汉堡轮辙试验的结果进行方差分析,研究了不同因素对汉堡轮辙深度的影响程度。结果表明:对汉堡轮辙变形深度的影响显著顺序依次为:试验温度胶结料黏度试件孔隙率试验次数;随着沥青胶结料黏度的增大变形深度减小比较明显,随着试验温度的升高变形深度成倍数增加,随着碾压次数的增加即孔隙率的减小,变形深度逐渐减小;四种因素对汉堡轮辙变形深度的作用效果均不具有显著性;对汉堡轮辙试验变形深度影响最大的是沥青混合料所选用的胶结料类型及试验温度。     

老化对水泥沥青复合胶结料粘弹特性的影响

为了研究老化对水泥沥青复合胶结料蠕变特性及粘弹性力学参数的影响,结合不同材料配比的水泥沥青复合胶结料的老化试验及蠕变试验,分析了老化时间及材料配比对复合胶结料粘弹性力学参数的影响。建立了考虑老化影响的粘弹性力学参数的演化方程;基于三元件四参数分数导数模型,提出了水泥沥青复合胶结料的老化因子,建立了水泥沥青复合胶结料的老化预测模型。研究表明:随着材料老化程度的加深,水泥沥青复合胶结料的弹性成分所占比例增加,粘性成分减少;水泥沥青复合胶结料的老化速度在老化前期变化较快,随老化时间增加老化速度减缓;适当提高沥青的用量可以在发生老化的情况下使材料仍具有较好的柔性及变形能力。所建立的老化因子能够同时反映老化时间、配合比等因素对水泥沥青复合胶结料粘弹特性的影响。     

Hardfill筑坝材料应力—应变特性与本构模型研究

胶凝砂砾石（Hardfill）材料是用少量胶凝材料将砂砾料固结得到的一种低强度筑坝新材料。通过对材料试验资料的分析,获得Hardfill材料应力—应变关系的特点为：表现出较典型的弹塑性材料应力—应变特征;在低应力水平表现为线弹性性质,当应力达到峰值强度的60%～80%后逐步进入弹塑性阶段,直至达到峰值强度;其后,应力随...     

双材料参数对界面端应力场分布规律的影响

利用反平面平板搭接界面端应力奇异性指数和应力场的理论公式,通过不同材料参数的组合和不同角度的变化,研究了正交异性双材料以及一种各向同性和一种正交异性双材料两种不同的结合材料反平面界面端应力奇异性和应力分布,得到了两种不同结合材料的应力分布规律和反平面平板搭接界面端断裂判据的初步理论。结果表明,随着Γ和θ的变化,不同结合材料界面端应力会呈现出不同的规律,这些规律可以作为在双材料界面端裂纹断裂准则或其它工程应用方面的依据。     

脆性材料SHPB试验中实现近似恒应变率加载必要性的研究

基于分离式霍普金森压杆（SHPB）试验的数值模拟,对脆性材料SHPB试验中是否需要实现近似恒应变率加载的必要性进行了研究。结果表明在脆性材料的SHPB试验中,即使整形入射应力波在反射应力波中产生了一个近似平台,脆性材料试样中仍旧存在显著的由惯性产生的径向围压,说明在SHPB试验中实现了由反射应力波中的近似平台所表征的近似恒应变率加载也不能表示SHPB试样中的应变率为近似恒定。因此,在脆性材料SHPB试验中应用波形整形技术并不能改变转折应变率表征SHPB试样中应力状态转变的特性。无论是否采用了波形整形技术,应用脆性材料SHPB试验结果时都应考虑惯性引起的径向围压的影响。     

The Properties and Applications of High-effective Mineral Admixture GRM for Concrete

To utilize industrial residue as building materials is not only the demand for modern concrete technology but also the requirements for maintaining ecological balance and sustainable development. CRM, a new high-effective mineral admixture for concrete, is developed recently from industrial residue, and the systematical studies on CRM's various properties have been performed. The laboratory tests, industrial tests and field applications have shown that CRM can be used as inorganic cementitious material to replace cement, and is also an excellent supplementary cementitious material tor high performance concrete (HPC).     

Dynamic flow resistivity based model for sound absorption of multi-layer sintered fibrous metals

The sound absorbing performance of the sintered fibrous metallic materials is investigated by employing a dynamic flow resistivity based model, in which the porous material is modeled as randomly distributed parallel fibers specified by two basic physical parameters: fiber diameter and porosity. A self-consistent Brinkman approach is applied to the calculation of the dynamic resistivity of flow perpendicular to the cylindrical fibers. Based on the solved flow resistivity, the sound absorption of single layer fibrous material can be obtained by adopting the available empirical equations. Moreover, the recursion formulas of surface impedance are applied to the calculation of the sound absorption coefficient of multi-layer fibrous materials. Experimental measurements are conducted to validate the proposed model, with good agreement achieved between model predictions and tested data. Numerical calculations with the proposed model are subsequently performed to quantify the influences of fiber diameter, porosity and backed air gap on sound absorption of uniform (single-layer) fibrous materials. Results show that the sound absorption increases with porosity at higher frequencies but decreases with porosity at lower frequencies. The sound absorption also decreases with fiber diameter at higher frequencies but increases at lower frequencies. The sound absorption resonance is shifted to lower frequencies with air gap. For multi-layer fibrous materials, gradient distributions of both fiber diameter and porosity are introduced and their effects on sound absorption are assessed. It is found that increasing the porosity and fiber diameter variation improves sound absorption in the low frequency range. The model provides the possibility to tailor the sound absorption capability of the sintered fibrous materials by optimizing the gradient distributions of key physical parameters.     

Fatigue life prediction and experiment research for composite laminates with circular hole

Based on the fatigue prediction model of exponential function and Whitney-Nuismer(WN) criterion of static strength for the composite material laminate with a circular hole, the stress correct factor (β) was put forward and a new fatigue prediction model for composite material laminate was set up. T300/KH304, which is recently studied and is a high capability composite material, was used as the raw material. In order to gain the factor β, the fatigue experiments of the laminates with holes in different diameters and the same ratio of width to diameter were conducted. The fatigue analysis and tests of the laminates with a hole 5 mm in diameter are carried out at different stress levels, and the results meet the engineering requirement. The simple, prompt and practical method is provided for the prediction of S-N curve of composite laminate with a circular hole.     

礼服设计中面料性能与立体造型效果

分析了立体构成技术用于礼服设计的适用性。测试了多种礼服常用面料的性能，采用立体构成技术对其进行三种常用造型设计，通过对不同性能的面料在相同板型下的立体造型效果比较，得出较适合的面料性能，为不同风格的礼服提供面料选择依据。     

Dynamic mechanical characteristics and application of constant resistance energy-absorbing supporting material

In deep underground engineering, rock burst and other dynamic disasters are prone to occur due to stress concentration and energy accumulation in surrounding rock. The control of dynamic disasters requires bolts and cables with high strength, high elongation, and high energy-absorbing capacity. Therefore, a constant resistance energy-absorbing (CREA) material is developed. In this study, the dynamic characteristics of the new material are obtained via the drop hammer tests and the Split Hopkinson Pressure Bar (SHPB) tests of the new material and two common bolt (CB) materials widely used in the field. The test results of drop hammer test and SHPB test show that the percentage elongation of CREA material is more than 2.64 and 3.22 times those of the CB material, and the total impact energy acting on CREA material is more than 18.50 and 21.84 times, respectively, indicating that the new material has high elongation and high energy-absorbing capacity. Subsequently, the CREA bolts and cables using the new material are developed, which are applied in roadways with high stress and strong dynamic disturbance. The field monitoring results show that CREA bolts and cables can effectively control the surrounding rock deformation and ensure engineering safety.     

Elasto-plastic analysis of masonry with anisotropic plastic material model

This paper establishes an anisotropic plastic material model to analyze the elasto-plastic behavior of masonry in plane stress state.Being an anisotropic material,masonry has different constitutive relation and fracture energies along each orthotropic axes.Considering the unique material properties of masonry,a new yield criterion for masonry is proposed combining the Hill’s yield criterion and the Rankine’s yield criterion.The new yield criterion not only introduces compression friction coefficient of shear but also considers yield functions for independent stress state along two material axes of tension.To solve the involved nonlinear equations in numerical analysis,several nonlinear methods are implemented,including Newton-Raphson method for nonlinear equations and Implicit Euler backward mapping algorithm to update stresses.To verify the proposed material model of masonry,a series of tests are operated.The simulation results show that the new developed material model implements successfully.Compared with isotropic material model,the proposed model performs better in elasto-plastic analysis of masonry in plane stress state.The proposed anisotropic model is capable of simulating elasto-plastic behavior of masonry and can be used in related applications.     

Research on the Sound Characteristic in the Active Sound Absorption and Isolation of the Piezoelectric Ceramics

压电复合材料的声学特性的理论研究

朱从云,牛继高,鲁付杰,邢会府,丁国芳

（中原工学院 机电学院）

中文摘要：

压电复合材料具有良好的力电耦合性能,被广泛用于诸如传感器,换能器,制动器等的主体材料,可以应用于振动与噪声的控制。基于此,本文用一片压电材料作为主动吸声系统中的吸声材料,通过布置于压电材料正前方的两个PVDF（Poly Vinylidene Fluoride）传感器,检测出平面入射声波与反射声波,利用压电材料的压电性能,在两片压电材料上分别加电压,使得反射声波与透射声波为零,从而达到主动吸声与主动隔声的目的。在平面入射声波入射下,进行了实验,取得了较好的主动吸声与主动隔声效果。

关键词：主动吸声;主动隔声;压电复合材料