Aiming at the existing problems such as low positioning accuracy and poor imaging resolution for damage detection of sparse array, a guided wave multi-mode fusion imaging method was proposed for damage detection of thin-walled structures based on the dispersion and multi-mode effects of guided wave. Firstly, the dispersion pre-compensation mechanism was adopted to construct excitation signal with dispersion pre-compensation to eliminate dispersion effect of ultrasonic guided wave response signal and correct phase distortion. In this way, the synthesis wavefront of guided wave signal achieved dynamic focusing. Secondly, the narrowband high frequency guided wave response signal dominated by A0 mode and S0 mode was extracted as detection waveforms by Chirp linear frequency modulated excitation signal. And the total focusing method was employed to establish the single mode total focusing imaging of guided by those detection waveforms, respectively. Finally, the significant difference in dispersion characteristics of guided wave for different modes were utilized to achieve guided wave multi-mode fusion imaging by fusion of various total focusing imaging results from A0 mode and S0 mode guided wave. The results show that the proposed guided wave multi-mode fusion imaging method achieves high precision positioning and high resolution imaging for both single and multiple damage detection of aluminum plate without baseline signals. And the maximum positioning error is 7.2 mm for multiple damage detection. In conclusion, the proposed multi-mode fusion imaging method can effectively improve the resolution and signal-to-noise ratio of damage imaging, suppress side lobe and avoid artifacts compared with single-mode focusing imaging. The proposed method can provide an effective way for multiple damage detection of thin-walled structures.

Aiming at high-pressure water jet hydraulic system profiles, AMESim is applied to two different hydraulic system simulation analysis, and better pressure and flow output characteristics are obtained using high-pressure wa-ter jet system with two double-acting hydraulic turbocharger driven. Besides, the impact hydraulic system accumula-tor volume of the hydraulic system are analyzed in this paper.

通过对工程机械应急救援中救援理论、救援技术和救援管理这一纵向思路的具体阐述，对工程机械应急救援研究体系进行了探讨。分析了上述三个方面具体涉及的问题，为建立工程机械应急救援系统的总体框架、管理、实施提供参考。

红外热成像检测技术是一种非接触式无损检测技术.目前,红外热成像检测技术在沥青路面道路施工工程领域的温度检测中的得到广泛应用,并得到较好的结果.沥青路面的早期损坏与沥青混合料的施工温度有关,道路施工的整个过程中沥青混合料的温度很高,传统的检测方法具有很大的局限性,不能很好的检测,而此时红外热成像检测技术就派上了用场.

Spraymec 7110WPC型湿喷台车进行喷射作业前，需要对其泵送充满度进行测定，以保证速凝剂配料的精确，达到湿喷配合比要求，确保施工质量。提出了一种简单易行的测定数学模型，并且对计算出的数据进行整理分析，为此类设备施工提供借鉴。

运用ANSYS有限元软件中的LY-DYNA模块进行了动力学仿真分析,针对不同性能凿岩参数对钻头破岩参数的影响进行了仿真分析,讨论了不同性能凿岩参数对于钻头破碎岩石的影响,得到了在不同性能凿岩参数匹配作用下岩石的破碎机理.为今后实际工程应用中凿岩台车凿岩钻进机具的合理选择与参数匹配提供了理论指导,同时也为凿岩台车的设计与改进提供了一定的参考依据.

通过阐述我国工程机械在自然灾害下的抢险功能,对工程机械应急救援的现状及需求进行了探讨。分析了我国工程机械应急救援装备的研究现状及存在的不足,指出了工程机械应急救援装备与相关技术的研发需求,以提高工程机械应急救援效率。

Taking 100t/38m portal crane as a research object, trying to use changing the height of a supporting leg to solve the problem of the resistance force when climbing the slope brought by of the girder. A finite element model of the girder was established by the general finite element software ANSYS. Structural strength and stiffness of the girder were analyzed, and achieved the expected results. Then analyzed the stress of the car and knew that resistance was offset by some percent through this improvement,meanwhile make the car passed smoothly and does not cause the motor overloaded.The research provides reference for the future research.

It introduces infrared how to apply the heat image formation to electric system, automotive industry, and other fields, while in consideration with its technical advantages to find usage in asphalt paving, which is to check temp in the asphalt mixture and detect thermal isolation during work operation before formulating logic operational processes, thus controlling the work quality.

In the light of domestic and international present maintenance procedures for potholes in asphalt pavements,the traditional procedure designs and their configurations are analyzed.On the basis of the permanent demands on pothole repair,a new repair procedure of the static hot rolling method is advanced,and a new patching equipment is designed.Furthermore,through indoor simulated experiment of pothole hot repair,the feasibility and adaptability of new repair method are proved.

On the basis of the ultimate aim and compatibility criterion of pothole repair in asphalt concrete pavements,the compatibilities of the asphalt binder and the aggregate,patching materials and old pavement materials are analyzed and researched.A good compatibility is beneficial to increase the performance and endurance of pothole repair.

对振捣机构的结构和工作过程进行分析,建立简化的物理模型,发现相位关系对振捣机构的惯性力有很大影响。建立了运动方程并采用数值分析软件Matlab对振捣过程进行仿真计算,得到了较合理的相位关系,为振捣机构的设计提供了参考依据。

为使读者全方位地了解国内高速公路沥青路面养护的情况,著名专家长安大学工程机械运用工程研究所所长康敬东教授在百忙之中接受本刊邀请,就相关问题作了深入探讨。

在公路工程中需要大量的碎石材料作为沥青混合料的骨料,其含量超过80%,而各种碎石除了要有一定的级配,还应脱水、脱泥、脱各种杂物.特别是当石料受泥土污染时,会严重影响其与沥青的粘附性,进而影响沥青混合料及其铺设路面的质量和耐久性.对于石料中泥土的处理方法通常有两种:第一种方法是在使用前将石料清洗干净、晾干或烘干后备用;第二种方法是用沥青材料或煤油进行预处理,即采用很少量(约0.5%～0.8%)的液态沥青或煤油对石料进行预拌和处理,使石料表面裹附一层很薄的油膜,以保证石料与沥青粘结可靠.

当前,多数沥青洒布车能够基本满足洒布量的精度要求,但是对沥青洒布的均匀性控制不好,洒布层常常出现纵向条纹(即明显的横向不均匀).

根据沥青路面裂缝填封的最终目的以及裂缝填封材料的受力状况,分析研究了沥青路面裂缝的填封机理,提出了获得理想维修效果的具体要求.

In order to check the effects of pavement cracks sealing and pot holes mend, the pavement failure types are summarized. The reasons of the failure after cracks sealing and pot holes mend are analyzed.

为了提高平地机冬季除雪的作业质量和作业效率,分析了平地机冬季除雪的特点和具体运用方法,给出了平地机切削和水平调整角的合理取值范围,论述了平地机联合除雪作业和破冰除雪作业的施工方法,总结了平地机冬季除雪的注意事项.

By adopting the current identification method,namely monitoring stator current with noninvasive transducers,the failure diagnoses of motor bearings are made.The feasibility and adaptability are proved by a verification experiment.

On the basis of grey theory model GM(1,1), the determination model of the number of broken bars in cast aluminum rotor is established, and a living example shows that its precision is high, and its computation is simple.