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空气载能空调房间输入■算法 及系统■成本应用分析
龚光彩?,尹丹
- , 2019,
Abstract: 通过分析辐射孔板的传热特性,结合金属辐射板和对流型空气处理末端的■分析方法,提出了空气载能辐射空调房间的输入■计算方法,并且基于■成本分析法,建立了空气载能辐射空调系统的■成本分析模型.在满足人体热舒适要求的前提下,以单位■成本为评价指标,对空气载能辐射空调系统、毛细管辐射空调系统和分体式空调加地暖系统进行■成本分析.研究发现:运用于办公建筑时,毛细管辐射空调系统的各单位■成本高出空气载能辐射空调系统1~3倍;运用于住宅建筑时,分体式空调加地暖系统全年的产品■单位成本为空气载能辐射空调系统的1.2倍.研究表明空气载能辐射空调系统的总体■经济性更好,该研究结果对空气载能辐射空调后期在工程上的实际推广应用具有一定的指导意义.
Based on the heat transfer process of orifice plate and the exergy analysis method of traditional mental radiant panel and convective air-conditioning terminal, the algorithm of room input exergy for air carrying energy radiant air-conditioning system(ACERS) was proposed. The exergy cost analysis model of ACERS was established by exergy cost analysis method. The unit exergy cost of three radiant air-conditioning systems including ACERS, capillary radiant air conditioning system and a combined system of split air conditioning with floor radiant air conditioning,was compared under the premise of thermal comfort. The results show that the unit exergy costs of capillary radiant air conditioning system are 1~3 times higher than that of ACERS in office buildings. The unit product exergy cost for the year of a combined system of split air conditioning with floor radiant air conditioning is 1.2 times higher than that of ACERS in residential building. It is found that the overall exergy economic performance of ACERS is superior to the other two radiant air-conditioning systems, which is of great significance for future engineering application of ACERS.
超限运输车辆通过T梁桥的合理横向位置分析
闫君媛,邓露,?
- , 2018,
Abstract: 对超限运输车辆通过多梁式简支T梁桥时的合理横向位置进行了分析.以我国公路桥梁中常见的中小跨径T梁桥为例,通过有限元分析提取了车辆在不同横向位置加载时梁底跨中截面处的最大弯曲应力,并对计算结果进行了对比,从优化结构受力的角度确定了超限运输车辆过桥时的最佳横向行驶位置.分析了桥梁跨径、主梁根数、主梁连接方式等因素对超限运输车辆过桥时的合理横向位置的影响.结果表明:超限运输车辆的横向加载位置对多主梁桥的结构响应有较大的影响;当主梁根数为奇数时,车辆的最佳横向行驶位置位于中心梁与其相邻梁的中间位置处;当主梁根数为偶数时,超限运输车辆的最佳横向行驶位置与桥面中心线重合;主梁之间的连接方式对车辆荷载作用下桥梁的结构响应影响显著.
This paper aims to investigate the optimal transverse position for overweight trucks to cross the simply-supported multi-girder bridges. Finite element analysis is performed for a group of prefabricated concrete T-beam bridges commonly used in China under the action of overweight trucks with varying transverse positions. The maximum bending stresses at the mid-span of the girders are extracted from finite element analysis and compared with each other. The optimal transverse position is determined from the point of optimizing the structural response. The effects of a few important parameters, including the length of bridge spans, number of girders and type of girder connections on the optimal transverse truck position are investigated. It is found that the transverse loading position of overweight trucks has a significant impact on the responses of multi-girder bridges. For the T-beam bridges with odd number of girders, the optimal transverse position for overweight trucks is in the middle between the center girder and the adjacent girder; for the T-beam bridges with even number of girders, the optimal transverse truck position is the centerline of the bridge. The influence of the girder connection condition on the bridge responses is significant.
I-V型夹芯板在近爆冲击波和 破片群联合作用下防爆性能研究
田力,?,胡建伟
- , 2019,
Abstract: 针对民用建筑物墙、板构件提出一种新型的I-V型夹芯板防护结构,采用非线性有限元软件LS-DYNA,开展近爆冲击波和破片群联合作用下I-V型夹芯板的防护性能研究.从质量损失、能量吸收和竖向峰值位移响应3个方面,研究了炸药比例距离、炸药起爆位置对夹芯板防护效果的影响,同时对夹芯板的实际防护性能进行了验证.结果表明:炸药比例距离对I-V型夹芯板的防护性能有较大的影响;不同炸药起爆位置对I-V型夹芯板的毁伤程度不同,在轴向增加起爆点的个数并不能显著增大I-V型夹芯板的毁伤程度;有I-V型夹芯板防护的钢筋混凝土板迎爆面只有少量混凝土脱落,且无钢筋外露,背爆面无混凝土脱落,也无钢筋外露,塑性变形区域较小,整体没有形成贯穿破坏,I-V型夹芯板的实际防护效果 很好.
This paper presents a new I-V type sandwich panel structure for civil building wall and plate, and uses the nonlinear finite element software LS-DYNA to study the explosion protection properties of I-V type sandwich panel under the combined loading of close-range blast wave and fragments. In terms of three aspects of mass loss, energy absorption and vertical peak displacement response, the influence of the explosive proportion distance, explosive initiation position on the protection effect of sandwich panels and the actual protective performance of sandwich panels were studied. The results show that the ratio of explosive distance has great influence on the protective performance of I-V type sandwich panels. The damage degree of different explosive initiation points to I-V type sandwich panels is different, and the number of initiation points in axial direction can not significantly increase the damage degree of I-V sandwich panels. There is only a small amount of detached concrete and no reinforcement exposed on the front surface, while on the back surface, no concrete falls off and no reinforcement exposes with lesser plastic deformation area,and there is no penetrating damage to the whole with the protection of I-V sandwich panels. The damage degree of the reinforced concrete slab with I-V sandwich panel is far less than that of the unprotected concrete slab.
楼板局部设缝框架结构概率地震需求分析
蒋洪波,邱洪兴,张敏
- , 2018,
Abstract: 楼板局部设缝框架通过在梁端设置贯穿楼板的通缝将楼板内纵筋与框架梁端分离,以实现“强柱弱梁”屈服机制.本文基于概率地震需求分析方法对该楼板局部设缝方法进行研究.首先利用楼板局部设缝框架振动台试验数据,验证采用OpenSees进行动力有限元分析的合理性;在此基础上,建立纯框架、传统框架、楼板局部设缝框架数值模型,选取22条地震动记录,对三种框架进行概率地震需求分析,从概率层面探究楼板和楼板局部设缝对框架结构抗震性能的影响.分析表明:楼板局部设缝可在一定程度上改善含现浇楼板框架结构的屈服机制,削弱现浇楼板带来的不利影响,提高传统框架的抗震性能以及结构的抗地震倒塌能力.
To implement the seismic design principle of “strong column and weak beam”,frame structure with local slot in floor slab is designed, where the continuous slot penetrating through the slab along the beam ends was set to separate the longitudinal reinforcement in the slab from the beam ends. Based on the probabilistic seismic demand analysis method, frame structure with local slot in floor slab was investigated. To investigate the accuracy of numerical model, shaking table test data was utilized to verify the calculated data of frame structure with local slot in floor slab modelling by the finite element software, OpenSees. The numerical models of frame structure without slab, conventional frame structure with cast-in-place slab, and frame structure with local slot in floor slab were established subsequently. Seismic performance was studied to explore the effect of the local slot of floor slab in the viewpoint of probability based on the probabilistic seismic demand analysis,which used 22 seismic ground motions. The results showed that the cast-in-place floor slab decreased the seismic performance. Besides,the slot in floor slab weakened the adverse influence of cast-in-place floor slab and increased the seismic performance and collapse-resistant capacity of frame structure.
T型件连接梁柱节点冲击试验研究和数值分析
霍静思,?,王海涛,张磊
- , 2018,
Abstract: 设计采用了T型件连接的2个半刚性钢结构梁柱节点试件,对试件施加落锤冲击荷载来模拟结构的动态倒塌效应,考察T型件翼缘和腹板的厚度对钢框架梁柱节点抗冲击性能的影响.通过试验获得节点试件的破坏形态及其冲击荷载和位移时程曲线,分析试件冲击过程动态响应规律以及节点动态转角和耗能能力.试验结果表明:节点试件的主要破坏形态是节点核心区域的T型件的翼缘或腹板断裂破坏和受弯变形,以及钢梁腹板扭曲变形;2个半刚性连接的节点试件的抗冲击转动能力主要受制于T型件部位,且由于T型件构件承载力不足,其最大转角均未到达FEMA350标准倒塌控制转角限值(θ = 0.109 rad)要求;T型件连接的半刚性节点相对普通全焊接的刚接节点的耗能能力和延性均有降低.采用ABAQUS软件建立了T型件连接梁柱节点子结构的有限元分析模型,通过分析T型件连接梁柱节点在冲击作用下内力发展规律可知,设计采用部分强度半刚性连接的T型件连接节点设计不利于构件向悬链线效应转换. 关键词:T型件;半刚性节点;动力性能;延性;有限元;内力分析
Two semi-rigid beam-column connection specimens with T-stubs of steel frame were designed. The impact tests using drop-hammer were conducted to simulate the collapse behavior under impact loading. The influence of thickness of T-stubs flange and web for the beam-column connection on the impact resistance of steel frame substructure was investigated. The failure modes and time histories of impact load and deformation were obtained,and the dynamic responses of the impact load and deformation time histories were analyzed as well as the dynamic rotation and energy dissipation of the substructures. Test results show that the failure modes of T-stub beam-column connection specimens mainly include the fracture and bending deformation of T-stub flange and web as well as distortional deformation of steel beam web. The rotation capacity of two connection specimens were dominated by the T-stubs,and their maximum rotations are less than the FEMA350 design limit (θ = 0.109 rad) due to the premature failure of T-stubs. The energy dissipation and ductility of semi-rigid beam-column connection specimens with T-stubs are inferior to the ordinary welded rigid beam-column connections. The finite element (FE) analysis model of T-stub beam-column connection was established using ABAQUS software. The internal force development of specimens during the impact loading was analyzed and it demonstrated that the T-stub beam-column connection with design of partial strength and semi-rigid connection degraded the formation of catenary action.
生物质/聚吡咯复合材料的电化学性能研究
钟文斌?,王传志
- , 2018,
Abstract: 在造纸行业中作为废液的木质素磺酸盐是一种含有甲氧基和酚羟基的生物质衍生物,由于具有可逆的氧化还原反应而提供赝电容.但木质素磺酸盐的导电性低,从而不能直接作为超级电容器电极.本文在含木质素磺酸钠(Lig)的体系中原位聚合吡咯(Py)制备了具有导电性能的木质素磺酸钠/聚吡咯复合材料(LP).通过扫描电镜(SEM)和傅里叶红外光谱(FTIR)测试对其形貌和结构进行表征.结果表明:当Lig与Py质量比为1 ∶ 1和电流密度为 1 A/g时,复合材料具有高的比电容(346.8 F/g), 相比于单纯聚吡咯(PPy)的比电容提高了约50 F/g.而且当电流密度从1 A/g升高到10 A/g时,LP1的倍率性能高达60.8%,比PPy提高了9.3%.在高电流密度10 A/g时,复合物LP1经过1 000次恒电流充放电后仍保留了47 %的电容值,表明复合物LP1表现出好的循环稳定性.
Lignosulfonate (Lig), a by-product of paper processing, is a biomass-derived compound including methoxy and phenolic functional groups, and it can generate pseudo capacitance by the redox reaction. However, it has a poor conductivity,limiting the application directly to supercapacitor electrode material. Herein, the good conductivity Lig/PPy composites were prepared by conducting polymer monomer (Pyrrole) via an in-situ polymerization under the Lig system. The morphology and structure were examined by scanning electron microscopy (SEM) and Fourier transformed infrared(FTIR). The effect of mass ratio of Rm(Lig : Py) on the electrochemical properties of the compound was reported. When the rational mass ratio of Rm = 1 ∶ 1 was used, LP1 had high capacitance of 346.8 F/g at 1 A/g. Lignosulfonate improved the specific capacitance by 50 F/g and 51.5 % to 60.8 % rate capability from 1 to 10 A/g. LP1 showed a capacitance retention of about 47% after 1 000 cycles at current density of 10 A/g, which indicated the composite had a good cycle life.
位错与纳米裂纹干涉的反平面问题
肖万伸?,席俊平
- , 2018,
Abstract: 针对位错与纳米裂纹干涉的反平面问题,提出了一种新方法,得出了精确解.首先利用复变函数中的保角变换方法,将直线裂纹问题化为孔板问题,再借助于柯西积分,获得了该问题的精确解答,然后分别推导出有、无表面效应作用时的应力场和位错力的解析表达式.数值结果表明:当裂纹尺寸缩减到纳米量级时,表面效应的影响使裂纹尖端附近的应力场和位错力减小,但随着裂纹长度的增大,表面效应的影响能力逐渐减弱,含表面效应的解答逐渐趋近于无表面效应的经典弹性理论解答.
A new method was presented to exactly solve the anti-plane problem of the interaction between a dislocation and nanoscale crack.Firstly,the problem of straight line crack was turned into an orifice plate problem by using conformal mapping method of the complex function. Secondly,the exact solutions of this problem were obtained by Cauchy integral theorem.Then,the stress field and image force with and without surface effect were formulated.The numerical results show that the stress field near crack tip and image force are decreased due to the surface effect when crack size is reduced to the nanometer level. However the influence of the surface effect can be gradually weakened with the increase of the crack length,and the solutions considering the surface effect approach to the classical elastic theory solutions without the surface effect.
熔覆层厚度对激光熔覆316L 涂层组织及性能的影响
陈刚,范才河?,曾广胜,刘彬
- , 2018,
Abstract: 利用YLS-6000型掺镱光纤激光器在27SiMn液压支架立柱表面进行不同厚度单道次316L合金粉末熔覆,采用光学显微镜(OM)、扫描电镜(SEM)、能谱(EDS)、显微硬度计及电化学分析等手段,研究了熔覆层厚度对涂层组织、力学性能及耐腐蚀性能的影响.结果表明:随着熔覆层厚度的增加,熔覆层组织由单一的柱状晶结构演变为平面晶、柱状晶和树枝状晶组成的层状结构,熔覆表层的显微硬度不断降低,熔覆层的自腐蚀电位和极化电阻率不断增大,自腐蚀电流密度不断减小;与0.3 mm、0.5 mm厚熔覆试样比较,1.0 mm厚熔覆层试样的自腐蚀电位和极化电阻率值均最大,分别达0.053 V和22.881 Ω·cm2,自腐蚀电流密度最小,为1.018 mA·cm-2.综合得出,1.0 mm厚熔覆层试样的耐腐蚀性最佳.
Single pass 316L alloy powder cladding with different thickness has been carried on the surface of 27SiMn hydraulic support column by using YLS-6000 type ytterbium doped fiber laser. The effect of cladding layer thickness on the coating structure, mechanical properties and corrosion resistance was studied by optical microscope (OM),scanning electron microscope(SEM),energy spectrum(EDS) microhardness meter and electrochemical analysis methods.The results show that,with the increase of cladding layer thickness,the cladding layer structure changes from a single columnar crystal to a layer structure including planar crystal,columnar crystal and dendritic crystal,the surface microhardness of the cladding layer decreases,the corrosion potential and polarization resistance rate increase and the corrosion current density decreases;Compared with 0.3 mm and 0.5 mm thick cladding specimens,both the corrosion potential and polarization resistance rate of 1.0 mm thick cladding layer samples show the largest values of 0.053 V and 22.881Ω·cm2,respectively,while the smallest corrosion current density of 1.018 mA·cm-2 occurs. It is concluded that 1.0 mm thick cladding layer exhibits the best corrosion resistance.
薄壁箱梁约束扭转的有限元分析及弯扭力矩新算法
夏桂云?,李传习,杨美良
- , 2019,
Abstract: 利用初参数法和传递矩阵,建立了薄壁箱梁约束扭转分析的有限元列式,导出了均布扭矩和均布双力矩的非结点荷载的等效公式.基于约束扭转的有限元位移解,进一步建立了弯扭力矩新算法,导出相应的刚度矩阵、均布扭矩和均布双力矩作用下的固端力公式,方便正应力和剪应力的计算.算例表明,本文的计算结果与理论值完全符合,所建立的薄壁箱梁约束扭转有限元列式、均布扭矩和均布双力矩的非结点荷载等效公式、弯扭力矩新算法公式正确.
Using initial parameter solutions and transfer matrix method,the finite element formulation for restrained torsion of a thin-walled box girder was presented. The equivalent nodal forces of distributing torque and bimoment acted on an element were also derived. Based on the displacement solutions of the finite element method for restrained torsion, a new algorithm for calculating the flexural-torsional moment was developed. The relevant stiffness matrix and fixed-end forces for distributing torque and bimoment acted on the element were established. It facilitated the calculation of normal stress and shear stress. The examples show that the calculation results of the proposed method agree well with the theoretical solutions, which proves that the stiffnesses for restrained torsion, equivalent nodal forces for distributing torque and bimoment acted on element as well as new algorithm for flexural-torsional moment are exact.
双向和三向土工格栅筋土界面特性对比试验研究
曹文昭,郑俊杰?,周燕君
- , 2019,
Abstract: 以双向土工格栅SS20和三向土工格栅TX160为对象,通过开展室内直剪试验和拉拔试验,并对拉拔试验中土工格栅试样4个断面的位移进行量测,研究了SS20和TX160的变形及筋土界面特性,对比分析了SS20和TX160方案的筋土界面剪应力发挥过程和作用机制、土工格栅变形、筋土界面剪胀(缩)特性和强度参数,同时探讨了试验方法对试验结果的影响.研究结果表明:拉拔试验中,TX160的筋土相互作用集中在拉拔端附近,而SS20沿试样全长均能较好地发挥其作用;相比于SS20,增大竖向压力可以更好地增强TX160与周围填料颗粒的相互作用;SS20方案的峰值摩擦角和残余摩擦角均大于TX160方案,但黏聚力刚好相反;竖向压力对直剪试验和拉拔试验所得筋土界面强度参数均有明显影响,实际工程应用中应根据土工格栅的实际应力状态确定合理的试验竖向压力.
Laboratory direct shear test and pullout test were conducted focusing on biaxial geogrid (SS20) and triaxial geogrid(TX160) to investigate the deformation and geogrid-soil interface behavior. The displacements of geogrid specimens were recorded at 4 sections in the pullout test. The development of geogrid-soil interface shear stress, geogrid deformation, shear dilatancy/shrinkage behavior and interface parameters were analyzed, and the effect of test methods on the testing results was also investigated. The results show that the interaction between the geogrid and soil of TX160 concentrates at the vicinity of pullout end. However, this interaction is well developed along the full length of SS20 specimens. Meanwhile, this interaction of TX160 can be better enhanced with the increase of vertical stress compared with that of SS20. Both the peak and residual friction angles of SS20 case are greater than that of TX160 case, while the cohesion is just opposite. The vertical stress has obvious effect on the geogrid-soil interface strength parameters obtained from both the direct shear test and pullout test. Thus, the vertical stress adopted in the test should be determined based on the actual stress status of the geogrid for engineering application.
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