壓力容器結構安全法規分析與實驗驗證之研究

壓力容器不論在設計、製造及檢驗上皆須符合相關規範之規定，各國政府依該地域與需求建立或採用相關法規，嚴格執行以保障容器使用上之安全性。然而，當引進引用國外相關法規所製造之容器時，其能否符合我國之標準與規定，在法規上應有相當程度之比較與分析。本研究係將我國CNS 9788及其相關標準，與國內較常見之他國壓力容器安全構造規範，包含日本JIS B 8265及JIS B 8266、英國PD 5500以及美國ASME Sec. VIII, Div. 1等，針對通則及設計板厚部份進行比較分析。結果發現，就通則而言，各國法規之間均有相當之差異；而設計板厚方面，以相同設計條件並以CNS第1種容器為比較基準，結果顯示，依規範種類、設計壓力範圍等不同，各國法規之間有相當之差異。由本研究分析歸納顯示，應無法建立所謂的「規範等效通則」，反而應在設計採用不同規範前，針對個案，將之與我國壓力容器規範，詳細比對與檢討，才能確保容器之使用安全。另外，本研究另針對法規及標準中，胴體開孔接管補強之規定，在靜態載荷作用且不實施補強板之情況下，透過改變幾何形狀以分析其接合處應力之分佈，以CAE軟體模擬並與實驗相互驗證。結果顯示，一般法規所規定之接合處內部施以圓角、倒角，確實可有效減緩由彎曲力矩所造成之局部高應力及減緩應力分佈之落差或驟增等影響，且模擬與實驗結果亦相當吻合；但實驗結果在幾何形狀間之差異，則較模擬分析者顯著。若另又承受時變載荷時，其應力變化程度則與受靜態初始負載時之應力大小呈正比關係；應適當地降低幾何不連續處之應力以避免應力及疲勞破壞。

關鍵字

壓力容器規範；規範比較；不連續應力

並列摘要

It is well known that in order to ensure the structural safety, the construction of pressure vessels shall comply with the codes or standards. In fact, the individual organizations or governments have drawn up their construction codes according to the regional characteristics. From the point view of Taiwan, the pressure equipment that complies with a foreign code and is directly imported and operated within Taiwan is inevitable. However, whether the equipment can fulfill the requirement of the local safety standard is then vital to the domestic industries. Thus, this research is to compare a few commonly used pressure vessel codes with the local CNS9788 and related standards. These codes include JIS B 8265 and B 8266, ASME Sec. VIII, Div. 1, and British PD 5500. Based on the comparative results, the deviations can be clearly observed even in the general construction rules. In addition, the minimum required thicknesses of shell and end plates are also analyzed. Based on the calculation of the deviation index that is defined by the current study, the required thickness of shells or end plates deviates quite severely except for cylindrical shells. As the conclusion, the so-called equivalence of codes is not recommended, nor directly applying any foreign codes without further detail study or analyses. In addition, this research also focuses on the variations of local stress distributed at the junction of a shell-nozzle in which the geometry varies. The shell-nozzle junction is not subjected to the membrane stress like the ones from the internal or external pressure since it can be linearly added, but to the bending moments caused by applied unidirectional forces. Two methods, including CAE and experiment, are used to obtain the stress distribution. It shows that the stresses of the arc-trimmed or chamfered corner exhibits relatively less severe than that of sharp angles. By the verification, the results of the experiment nearly coincide with the CAE simulation results. In addition, the alternating amplitude of stress is proportional to the initial static load when the nozzle is subjected to dynamic load. Thus, it is necessary to adopt appropriate method for decreasing the local stresses located at the shell-nozzle junction to avoid stress or fatigue damage in design.

並列關鍵字

Pressure Vessel Codes ； Comparisons of Codes ； Discontinuous Stress

參考文獻

[3] 沈育霖、黎文龍、曾百由，國外壓力容器標準之國內適用性研究，研究計劃報告IOSH95-S308，台北：行政院勞委會勞安所，2007，第1頁。

[4] John D. Fishburn, “A Single Technically Consistent Design Formula for the Thickness of Cylindrical Sections Under Internal Pressure,” J. Pressure Vessel Tech., Vol. 129, Issue 1, Feb. 2007, pp. 211-215.

[6] Brian B. Kerezsi, and John W. H. Price, “Using the ASME and BSI codes to predict rack growth due to repeated thermal shock,” Intern. J. of Pressure vessels and Piping, Vol. 79, Issue 5, May 2002, pp. 361-371.

[7] K. Behseta and S. Schindler, “On the design of the tubesheet and the tubesheet-to-shell junction of a fixed tubesheet heat exchanger,” Intern. J. of Pressure Vessels and Piping, Vol. 83, Issue 10, October 2006, Pages 714-720.

[8] Rao KR, editor, “Companion guide to the ASME boiler & pressure vessel code,” New York: ASME Press, vol. 2, 2002.

國際替代計量

壓力容器結構安全法規分析與實驗驗證之研究

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