压力容器寿命控制方法

LIFE CONTROL METHOD FOR PRESSURE VESSEL

对于各类压力容器 ,尽管它们的预测寿命可能完全不同 ,但都是按有关规程统一规定的检修周期进行检修的。在这种检修周期事先指定的情况下 ,寿命预测方法已无法保证结构安全 ,这也是压力容器发生事故的主要原因之一。为此 ,提出一种压力容器寿命控制方法 ,建立含多种损伤的寿命控制方程和常用的单损伤寿命控制公式 ,并对疲劳、应力腐蚀和蠕变等具体情况下的压力容器寿命控制进行讨论。寿命预测是从缺陷的初始尺寸积分到临界尺寸来估算寿命的 ,而寿命控制正好与之相反 ,是事先指定寿命 ,然后反求初始缺陷尺寸 ,并通过无损检测可靠性方法检出结构中大于该尺寸的缺陷 ,对检出的缺陷进行维修或更换相应的零部件 。

Although all kinds of pressure vessels have the different predicting lives, they are inspected according to unified inspection period. When the inspection period is predetermined, the life prediction method cannot insure the structural safety, which is one of the prime reasons of pressure vessel accident. A new life control method for pressure vessel is presented. The life control equation of multiple damage and general life control formula of single damage are established. The life control equations for fatigue, stress corrosion and creep are discussed in detail. The life prediction is to estimate the life when the flaw initial size and critical size are known. On the contrary, the life control is to estimate the flaw initial size at the predetermined life. Nondestructive test would be used to detect the flaws whose sizes are bigger than the allowable initial size estimated by the method, and corresponding repair or replacement of parts or components would insure the reliability and safety of structure in its lifetime.