图。 2 。 (一)变化的因素吨增加壳牌参数为通过厚度缺陷; (二)依赖因子质谱缺陷深度的增加壳牌参数的表面缺陷。
首先考虑的结果显示在图。 2款( a ) 。虽然b值集的严重性,强调扩增对剩余的韧带,由于管胀,只有温和影响的SH = sref的比例,特别是对长期缺陷( la6.0 ) 。较短的裂缝( 1 ( 4.0 ) ,依赖的SH = sref比对B有点更加明显。例如,在2.0升的应力比,上海= sref ,改变w0.35的B 1.61 w0 0.55的B 0.62 。然而,应当强调的是,这种行为不一定
转化为弱影响参数B对爆裂强度,因为,例如,增加一倍, b值将意味着减少了大约30 %的SH = sref比率。事实上,因档游大为这将是讨论在第4节,因为没有压力管道的接触(从而标志着塑料地方不稳定其余韧带) ,小的压力,增加磨做负荷迅速蔓延的原因损行竖坏的地区,其余的韧带与强大的影响爆裂强度。
考虑未来的结果显示在图。 2款( b ) 。有固定的B值为1.61 ,应力比上海= sref异强烈,特别是对深层次问题,在短期内打击范围( l_ 2.0 ) 。在此短暂的地区,上海= sref比率相对不敏感的缺陷长度为所有的A / T型比率。弱依赖的SH = sref ,比对缺陷长度升“ 2.0来自应力场的看法,即在剩下的韧带差异主要是由于缺陷深度不再缺陷。类似的趋势也得到了其他b值。这些结果清楚地表明,经济增长的短期和深层次问题(这可能是在例行检查未被发现)跨越管壁厚由于疲劳或进一步腐蚀机制可能有强大的不利影响的结构完整性管道或容器。此外,很短(长( 3.0 )和深( a/ta0.8 )的缺陷,未能强调了通过厚度缺陷高于相应的破裂应力的表面缺陷。虽然没有涉及在目前情况下,这种行为可能与泄漏先打破条件[ 18 ]其中韧带失败的表面缺陷,通过建立一个稳定,厚度缺陷。
Fig. 2. (a) Variation of factor MT with increased shell parameter for a through-thickness defect; (b) Dependence of factor MS on defect depth with increased shell parameter for a surface defect.
Consider first the results displayed in Fig. 2(a). While the b-value sets the severity of stress amplification on the remaining ligament due to pipe bulging, there is only a moderate effect on the sh=sref -ratio, particularly for long defects (la6.0). For shorter cracks (l(4.0), the dependence of the sh=sref -ratio on b is a little more pronounced. For example, at l 2.0 the stress ratio, sh=sref , changes from w0.35 for b 1.61 to w0.55 for b 0.62. However, it should be emphasized that such behavior does not necessarily
translate into a weak effect of parameter b on the burst strength since, for example, doubling the b-value would imply a reduction of circa 30% in the sh=sref -ratio. Indeed, as it will be discussed in Section 4, as the failure pressure for the pipe
图。 2 。 (一)变化的因素吨增加壳牌参数为通过厚度缺陷; (二)依赖因子质谱缺陷深度的增铅则加壳牌参数的表面缺陷。
首先考虑的结果显示在图。 2款( a ) 。虽然b值集的严重性,强调扩增对剩余的韧带,由于管胀,只有温和影响的SH = sref的比例,特别是对长期缺陷( la6.0 ) 。较短的裂缝( 1 ( 4.0 ) ,依赖的SH = sref比对B有点更加明显。例如,在2.0升的应力比,上海= sref ,改变w0.35的B 1.61 w0 0.55的B 0.62 。然而,应当强调的是,这种行为不一定
转化为弱影颂弊响参数B对爆裂强度,因为,例如,增加一倍, b值将意味着减少了大约30 %的SH = sref比率。事实上,因为这将是槐樱棚讨论在第4节,因为没有压力管道is approached (thereby marking the plastic local instability of the remaining ligament), small increases in the pressure loading causes rapid spread of the damaged area in the remaining ligament with strong impact on the burst strength.
Consider next the results displayed in Fig. 2(b). For a fixed value of b 1.61, the stress ratio sh=sref varies strongly, particularly for deep flaws, in the short crack range (l_ 2.0). After this transient region, the sh=sref -ratio is relatively insensitive to flaw length for all a/t-ratios. The weak dependence of sh=sref -ratios on flaw length for l> 2.0 derives from the observation that stress fields in the remaining ligament vary primarily due to flaw depth for longer flaws. Similar trends are also obtained for other b-values. These results clearly show that the growth of short and deep flaws (which might be undetected during routine inspection) across the pipe wall thickness due to fatigue or further corrosion mechanisms may have a strong adverse
接近(从而标志着塑料地方不稳定其余韧带) ,小的压力,增加负荷迅速蔓延的原因损坏的地区,其余韧带强大影响爆裂强度。
考虑未来的结果显示在图。 2款( b ) 。有固定的B值为1.61 ,应力比上海= sref异强烈,特别是对深层次问题,在短期内打击范围( l_ 2.0 ) 。在此短暂的地区,上海= sref比率相对不敏感的缺陷长度为所有的A / T型比率。弱依赖的SH = sref ,比对缺陷长度升“ 2.0来自应力场的看法,即在剩下的韧带差异主要是由于缺陷深度不再缺陷。类似的趋势也得到了其他b值。这些结果清楚地表明,经济增长的短期和深层次问题(这可能是在例行检查未被发现)跨越管壁厚由于疲劳或进一步腐蚀机制可能有一个强有力的不利