环保型白色山羊缩纹革制作技术关键

对白色无铬鞣环保型山羊缩纹革制作工艺中各工序的工艺技术关键进行了探讨,重点介绍如何操作控制使山羊皮背部与边肷部位,缩纹大小均匀一致,减少部位差,提高次皮档次和成革利用率,达到皮革出口标准的要求。

进口蓝湿革制造缩纹家具革的工艺技术

进口蓝湿革经过严格挑选、组批、回软、脱铬、软化使其性质达到均匀一致后,再用收敛性强的醛类和植物鞣剂进行鞣制缩纹、多次加脂、分步填充和精细化的整理,生产的缩纹家具革高档、大方、粗犷,用低档次的蓝湿革制造出高档产品,提高了经济效益。

绵羊缩纹服装革工艺浅析

对绵羊缩纹服装革生产过程中基本工艺思路的分析,并借助英国SEATON公司的化工材料进行了工艺介绍。

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对绵羊缩纹革涂饰方法、机械操作进行了较为系统的介绍。通过对涂饰前革坯的挑选,涂饰过程中的机械操作以及涂饰化料的选择与搭配等方面进行合理控制,成革的质量可以显著提高。

拉深新能源动力电池壳表面颈缩纹的研究

为了探明多道次拉深电池壳表面产生颈缩纹的原因及其对3003铝合金板料力学性能的影响,对3003铝合金多道次拉深进行了显微组织分析,并对其原材料3003铝合金进行力学性能、金相组织、化学成分以及原材料生产过程分析.研究结果表明:有颈缩纹缺陷的电池壳原材料的晶粒组织粗大且不均匀,其板料延伸率明显偏低.由于3003铝合金板料生产过程中退火温度过高、保温时间过长而形成的不均匀粗晶导致了多道次拉深时变形不均匀,最终表现为颈缩纹,而延伸率是影响颈缩纹形成和反映颈缩纹材料特征的参量之一.

1515型复动式单花筒多臂机的缩纹处理

１５１５型复动式单花筒多臂机的缩纹处理石维龙（南通市色织二厂）１前言在棉织生产中，国产多梭箱装置大多数采用的是４×１多梭箱装置，龙头机大多数采用１５１５型复动式单花筒多臂机。在色织生产中，我们常碰到一些特殊的织物，其织物组织结构是以平纹和小提花相互混...

水牛缩纹家具革生产工艺

简要介绍了我国南、北方水牛皮的特点 ,并给出了水牛缩纹家具革湿加工工艺。

绵羊皮缩纹革工艺探讨

重点介绍了德赛尔化工实业有限公司皮化产品在生产绵羊缩纹革方面的工艺要点和工艺规程。

山羊皮缩纹鞋面革生产工艺

对山羊皮缩纹鞋面革的生产工艺,质量要求及生产过程中的注意事项进行了讨论和总结。

环保型植鞣缩纹革制作技术关键

对无铬鞣环保型山羊缩纹革制作工艺中各工序的工艺技术关键进行探讨，重点介绍如何操作控制使山羊皮背部与边肷部位，缩纹大小均匀一致，减少部位差，提高次皮档次和成革利用率，达到皮革环保标准的要求。

木竹地板含水率及横纹胀缩性的研究

本文研究了17种木竹地板的含水率、宽度和厚度的逐月变化。同时检查其拼合效果、弯曲和开裂情况。试验结果表明,14种木地板的含水率和宽度在一年中的变化,存在一定的规律性,并且与空气湿度和温度的变化有密切关系。根据相邻二月地板宽度的差值,提出在龙岩地区铺装木地板的适宜季节,最后对17种木竹地板作出初步评价。

Failure characteristics and its influencing factors of rock-like material with multi-fissures under uniaxial compression

The compression test on rock-like specimens with prefabricated closed multi-fissures made by pulling out the embedded metal inserts in the precured period was done on the servo control uniaxial loading instrument. The influence of fissure inclination angle and distribution density on the failure characteristics of fissure bodies was researched. It was found that, the fissure inclination angle was the major influencing factor on the failure modes of fissure bodies. The different developmental states of micro-cracks would appear on specimens under different fissure inclination angles. However, the influence of fissure distribution density on the failure mode of fissure bodies was achieved by influencing the transfixion pattern of fissures. It was shown by the sliding crack model that, the effective shear, which drove the relative sliding of the fissure, was a function of fissure inclination angle and friction coefficient of the fissure surface. The strain-softening model of fissure bodies was established based on the mechanical parameters that were obtained by the test of rock-like materials under the same experimental condition. And the reliability of experimental results was identified by using this model.

Cracking process of rock mass models under uniaxial compression

Anisotropic strength and deformability of the rock mass with non-persistent joints are governed by cracking process of the rock bridges. The dependence of cracking process of jointed rock masses on the two important geometrical parameters, joint orientation and joint persistence, was studied systematically by carrying out a series of uniaxial compression tests on gypsum specimens with regularly arranged multiple parallel pre-existing joints. According to crack position, mechanism and temporal sequence, seven types of crack initiations and sixteen types of crack coalescences, were identified. It was observed that both tensile cracks and shear cracks can emanate from the pre-existing joints as well as the matrix. Vertical joints were included and coplanar tensile cracks initiation and coalescence were observed accordingly. For specimen with joint inclination angle ,8=75~, it was found that collinear joints can be linked not only by coplanar shear cracks but also by mixed tensile-shear cracks, and that a pair of them can form a small rotation block. Seven failure modes, including axial cleavage, crushing, crushing and rotation of new blocks, stepped failure, stepped failure and rotation of new blocks, shear failure along a single plane and shear failure along multiple planes, were observed. These modes shift gradually in accordance with the combined variation of joint orientation and joint persistence. It is concluded that cracking process and failure modes are more strongly affected by joint orientation than by joint persistence, especially when joint inclination angle is larger than 45~. Finally, variations of macroscopic mechanical behaviors with the two geometrical parameters, such as patterns of the complete axial stress-axial strain curves, peak strength and elastic modulus, are summarized and their mechanisms are successfully explained according to their different cracking process.

Cracks coalescence mechanism and cracks propagation paths in rock-like specimens containing pre-existing random cracks under compression

The mechanism of cracks propagation and cracks coalescence due to compressive loading of the brittle substances containing pre-existing cracks （flaws） was modeled experimentally using specially made rock-like specimens from Portland Pozzolana Cement （PPC）. The breakage process of the specimens was studied by inserting single and double flaws with different inclination angles at the center and applying uniaxial compressive stress at both ends of the specimen. The first crack was oriented at 50＆#176; from the horizontal direction and kept constant throughout the analysis while the orientation of the second crack was changed. It is experimentally observed that the wing cracks are produced at the first stage of loading and start their propagation toward the direction of uniaxial compressive loading. The secondary cracks may also be produced in form of quasi-coplanar and/or oblique cracks in a stable manner. The secondary cracks may eventually continue their propagation in the direction of maximum principle stress. These experimental works were also simulated numerically by a modified higher order displacement discontinuity method and the cracks propagation and cracks coalescence were studied based on Mode I and Mode II stress intensity factors （SIFs）. It is concluded that the wing cracks initiation stresses for the specimens change from 11.3 to 14.1 MPain the case of numerical simulations and from 7.3 to 13.8 MPa in the case of experimental works. It is observed that cracks coalescence stresses change from 21.8 to 25.3 MPa and from 19.5 to 21.8 MPa in the numerical and experimental analyses, respectively. Comparing some of the numerical and experimental results with those recently cited in the literature validates the results obtained by the proposed study. Finally, a numerical simulation was accomplished to study the effect of confining pressure on the crack propagation process, showing that the SIFs increase and the crack initiation angles change in this case.

Effects of strain rate and temperature on microstructure and texture for AZ31 during uniaxial compression

In order to investigate the effects of strain rate and temperature on the microstructure and texture evolution during warm deformation of wrought Mg alloy,AZ31 extruded rods were cut into cylinder samples with the dimension of d8 mm×12 mm.The samples were compressed using a Gleeble 1500D thermo-mechanical simulation machine at various strain rates(0.001,0.01,0.1,1 and 5 s- 1)and various temperatures(300,350,400 and 450℃).The microstructure and texture of the compressed samples at the same strain under different deformation conditions were studied and compared by electron backscatter diffraction(EBSD)in scanning electron microscope(SEM).The results show that the size of recrystallized grains in the deformed samples generally increases with the decrease of strain rate and the increase of temperature.After 50%reduction,most basal planes are aligned perpendicular to the compression direction at relatively high strain rate(>0.01 s- 1)or low temperature(<350℃).The optimized strain rate is 0.1 s- 1for uniaxial compression at 300℃,which produces about 80%of small grains(<5μm).

Wing crack propagation model under high hydraulic pressure in compressive-shear stress state

A new wing crack model subjected to hydraulic pressure and far-field stresses was proposed considering the effect of hydraulic pressure in wing crack and the connected part of the main crack on the stress intensity factor at the wing crack tip. With the equivalent crack length Ieq of the wing crack introduced, the stress intensity factor Kl at the wing crack tip was as- sumed to the sum of two terms： on one hand a component K1^（1） for a single isolated straight wing crack of length 21, and subjected to hydraulic pressure in the wing crack and far-field stresses; on the other hand a component K1（2） due to the effective shear stress induced by the presence of the equivalent main crack. The lateral tensile stress and hydraulic high pressure are the key factors that induce crack propagation unsteadily. The new wing crack theoretical model proposed can supply references for the study on hydraulic fracture in fractured masses, hydraulic fracturing in rock masses.

Mode-I-crack compression modeling and numerical simulation for evaluation of in-situ stress around advancing coal workfaces

The relatively high stress probably leads to generation of a fractured or even instable area around a working coalface. Also, the generated weak area often evolves into an easy-infiltrating field of water/gas to greatly increase probability of accident occurrence. To reveal the distribution of high stress around working faces, we put forward the mode-I-crack compression model. In this model, the goaf following a working face is regarded as a mode-I crack in an infinite plate, and the self-gravity of overlaying strata is transformed into an uniform pressure applied normal to the upper edge of the model crack. Solving this problem is based on the Westergaard complex stress function. For comparison, the software RFPA-2D is also employed to simulate the same mining problem, and furthermore extendedly to calculate the stress interference induced by the simultaneous advances of two different working faces. The results show that, the area close to a working face or the goaf tail has the maximum stress, and the stress is distributed directly proportional to the square root of the advance and inversely proportional to the square root of the distance to the working face. The simultaneous advances of two neighboring working faces in different horizontals can lead to extremely high resultant stress in an interference area.

Strength failure and crack coalescence behavior of sandstone containing single pre-cut fissure under coupled stress, fluid flow and changing chemical environment

In order to study the strength failure and crack coalescence characteristics of cracked rocks, uniaxial compression experiments were conducted on cylindrical sandstone specimens, sampled from Longyou Grottoes of Zhejiang Province, China, with a single pre-cut crack soaking in different chemical solutions. Based on the results of uniaxial compressive test under different chemical solutions and velocities of flow, the effect of strength and deformation characteristics and main modes of crack coalescence for cracked rocks under chemical corrosion were analyzed. The results show that the pH value and velocity of the chemical solutions both have great influence on the sandstone sample's uniaxial compressive strength and deformation characteristics. Cracked sandstone samples are tension-destructed under uniaxial compression, and the crack propagation directions are consistent with the loading direction. The phenomena of crack initiation, propagation and coalescence of sandstone are well observed. Four different crack types are identified based on the crack propagation mechanism by analyzing the ultimate failure modes of sandstone containing a single pre-cut fissure. The failure process of specimen in air is similar with the specimen under chemical solutions, however, the initial time of crack occuring in specimen under chemical solutions is generally earlier than that in the natural specimen, and the crack propagation and coalescence process of specimen under chemical solutions are longer than those of the natural specimen due to softening of structure of rock caused by hydro-chemical action. Immersion velocity of flow and chemical solutions does not have influence on the ultimate modes of crack coalescence.