裂纹

Fatigue cracking is one of the major modes of premature distresses in asphalt pavements. Cracks of asphalt pavements start as microcracks and later propagate, densify, and coalesce due to repeated traffic loading or low temperature thermal stresses or combinations of both to form macrocracks, and result in structural distresses of asphalt pavements.

疲劳开裂是沥青路面主要的早期破损形式之一，由于交通荷载和低温应力的反复作用，沥青路面中的微裂纹不断扩展、增密并贯穿连通形成宏观裂纹，导致。。。

By means of chemical analysis, rigidity test, metallographic examination and fracture analysis, it was found that the main reason for the backup roll's desquamation was possible crack headspring which was offered by impurity in interior tissue.

通过对其进行成分分析、硬度测试、金相检验及断口分析，确定了支撑辊剥落的原因：内部组织中夹杂物等提供了可能的裂纹源，裂纹在此产生并逐渐扩展，起初因摩擦磨损在轧辊表面形成轻微点蚀及小块剥落，受到辊型和载荷等其他外部因素的影响，在应力集中部位产生大面积剥落，从而导致轧辊报废。

By means of chemical analysis,rigidity test,metallographic examination and fracture analysis,it was found that the main reason for the backup roll's desquamation was possible crack headspring which was offered by impurity in interior tissue.The crack came into being here and then extended outward gradual...

通过对其进行成分分析、硬度测试、金相检验及断口分析，确定了支撑辊剥落的原因：内部组织中夹杂物等提供了可能的裂纹源，裂纹在此产生并逐渐扩展，起初因摩擦磨损在轧辊表面形成轻微点蚀及小块剥落，受到辊型和载荷等其他外部因素的影响，在应力集中部位产生大面积剥落，从而导致轧辊报废。

It is demonstrated that the pipe meets the conditions that the crack is stable and the leakage is detectible which LBB asks for, and it also satisfies the time request from the beginning of leak to the moment at which the crack is unstable.

经验证，该管道符合LBB技术对于裂纹稳定性及泄漏量可探测性的条件，满足从开始泄漏到裂纹失稳的时间要求。

The big size anvil used wax as plasticizer at dewaxing. The main dewax stage from 270℃ to 400℃. Have gas release summit between 400℃ and 750℃. Setting up rational process date at dewax stage can prevent cemented carbide crack. But the crack will appear and impair the quality of products when the microcrack flaw inner compact.

石蜡工艺大制品顶锤在脱蜡阶段，270℃-400℃为成型剂石蜡的主要脱除阶段，400℃-750℃时有气体释放高峰状态，在脱蜡预烧阶段设置合理工艺参数可以防止合金裂纹，但压坯本身若存在微裂纹缺陷，必然会显露出来影响产品质量。

In the high-speed steel with hard temper by dipping in water, rupture the gap that the process includes initiative carbide crackle to cause appears, or cause as a result of martensite matrix organization in area of crackle endmost flexibility decrease get together force arises.

在淬硬的高速钢中，断裂过程包括起始碳化物裂纹引起的缝隙出现，或裂纹末端的弹性区中由于马氏体基体组织造成的减聚力产生。

Cracks started formin' in the ground, then those cracks ripped wide open.

地面上开始出现裂纹，然后很快裂纹扩大开来。

Consequently,the model obviates the needs for fitting and reducesthe arbitrariness to minimum,if the law of crack growth in mesoscopic level,i.e.,theR curve,is known.Naturally,the model relates the macrostructural response of thesolid with its mesotructure(the density,size and orientation of the crack).

如果细观微裂纹扩展阻力，即R曲线已知，无需再在演化规律中引入大量的经验参数，即可自然地建立起材料的细观结构(微裂纹尺寸，密度和方位)演化与材料的宏观响应的联系。

The characteristic of machined surface of high speed machining aluminum alloy 7050-T7451 is researched by micrographic experiments and analysis. The formation mechanics of machined metamorphism layer has been analyzed and studied. The dislocation-energy model in machined metamorphism layer was established and applied to explain the micrographic mechanics work-hardening using the thermo-mechanical coupling deformation theory and dislocation theory. The experimental results show that the interaction of high dislocation density effect on hardening is more remarkable than that of thermal stress in high speed machining.

利用显微观察方法对铝合金7050-T7451高速铣削加工的工件表面断面和不同深度的表层的微观形貌特征进行系统的研究，确定了高速切削加工铝合金7050-T7451的表面变质层深度为30～35μm；应用位错能量研究了高速铣削加工过程的热力耦合对变质层的影响机理，并通过微观形貌观察证明：与普通切削相比，高速铣削表层塑性变形的能量和位错密度更高；建立了位错密度的加工硬化的动力学模型，研究了加工硬化的热-力耦合形成机理；对微观裂纹的形成机理进行了理论分析，证明位错密度高的高速切削过程中较低速加工更容易产生明显的微裂纹，从分子级乃至原子级的水平进一步揭示高速切削加工表面变质层的形成特征。

Starting with the toughening of ceramics, the subcritical crack growth model on monotonical loads was set up for the first time, and the V—K curves in the subcritical crack growth process and the effects on them were obtained by use of computer simulation.

首次从材料增韧入手，建立了单向载荷形式下亚临界裂纹扩展模型，并利用计算机数值计算获得裂纹扩展过程中V—K曲线及其影响因素，由此对多晶陶瓷材料疲劳现象的本质进行了分析。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。