打底层焊道裂纹的优化检测方法

通过采用多种无损检测方法对船体焊道打底层微裂纹缺陷检出率进行对比分析和应用,从实用性和有效性两个方面确定了对焊接过程和完工后焊缝检测方法的研究和选择,最终优化了检测方法;并且消除和避免了大量裂纹类缺陷的存在,确保了焊接产品的完工质量,提高了船体的整体安全性。

超声波检测Y型节点打底层焊道异常信号研究

对超声波检测获取的异常信号分析是缺陷定性的主要手段。裂纹缺陷是焊接过程经常出现和最严重的缺陷之一,在所有标准和规范里都严禁存在。文章通过对Y型全熔透焊缝采用FCAW-CO_2焊接方法的焊接过程质量进行了多角度和多手段的综合评价对比,确定了异常信号缺陷的性质和优化了无损检测工艺参数。

焊缝根部缺陷的综合检测

通过综合应用无损检测技术,对船体分段合拢焊缝打底层焊道出现的异常超声波反射信号进行分析及评价。以射线、磁粉等检测手段分析了异常信号所对应的缺陷性质及定性可靠性,为根部微裂纹缺陷检测和提高焊接工艺规范提供了依据。

Experimental study on tensile failure process of double-K fracture parameters in roller compacted concrete layer

Study on failure of soft stratum of roller compacted concrete (RCC) is an important aspect of stability of high RCC dam. Six kinds of specimens with different interfaces were investigated by wedge splitting method. Double-K fracture parameters (initial fracture parameter and unsteady fracture parameter) were calculated by the concrete double-K fracture theory. It is indicated that the approach of construction joint or old joint after RCC final set is the most efficient among the six cases, and its fracture parameter is the largest among them. Its propagation path is sinuous. Its failure surface is scraggly. Bedding plane crack fails at the underside of the concrete surface, bond course or the surface between them for each approach. So disturbance on the underside of the concrete surface should be avoided or decreased at best during RCC construction.