During design of pressure vessel, I came across this issue number of time. Unfortunately, ASME VIII Div.1 doesn’t give a clear picture, whether to add the undertollerance in the min. required thickness as calculated by ASME VIII Div.1 ASME VIII Div. 2, give a clear cut understanding on this issue, can clears all ambiguity. (Clause…
Ok, TEMA Ninth edition is here. Other Than complete change in Page Indexing (Page number), Following are note worthy changes from eigth edition : Followings are Prominent Changes and Listed at TEMA website 1. New rules for flexible shell elements (expansion joints), which are based on a Finite Element Analysis (FEA) approach. 2. Tables for…
It is customary for most vessel designers to establish the minimum vessel shell and trend thickness according to the pressure temperature conditions and then calculate the thickness required at the bottom head seam due to bending moments imposed by wind or earthquake forces. Stresses in the longitudinal direction are involved nod the following notation maybe…
We design pressure vessel for longitudinan and circumferencial stresses. Now whats that? Ok, longitudinal stresses comes on circumferencial joints, where as circumferencial stresses comes on longitudinal joints. And to add cherry on top circumferencial stresses are twise that of longitudinal stresses. If you are not yet twisted your tongue, and to avoid that we generally…
OK.. The Billion dollar Question… Just to make it easy, we will break the pressure vessel in two category..1. Pressure Vessel without external loading &2. Pressure Vessel With external Loading For Category 1, we can use ASME Section VIII Div. 1 directly, where as for Category 2, we need to consider additional loadings. And for…
Failure: Failure of a structure is an event, the transition from a normal working state, where the structure meets its intended requirements, to a failed state, where it does not meet its requirementsLimit states: A limit state is a structural condition beyond which the design performance requirements of a component are not satisfied. Limit states…
The differences have to be taken into consideration by both designer and welder. The high thermal expansionand low thermal conductivity of the austenitic steels lead to higher shrinkage stresses in the weld thanwhen carbon and ferritic steels are used. Thin sections of austenitic steels may therefore be deformed when an abnormally high heat input is…
In pressure Part Industry we use various type of material. Typically in industry like this, we mainly classify material as Mild Steel also known as Carbon Steel, we also use low & high alloy steel & yes stainless steel! What diffrentiate staineless steel from Carbon steel is its corrosion resistance properties, whcih comes because of…
Design : 2 : Shell (External Pressure)
External pressure can be due to internal negative Pressure, or external loading like wind, earthquake etc. or live load, snow load etc. One can design Pressure vessel for either sever combination of various load or for most possible occurrence of load combination. Load combinations are given in respective ‘Building Code’ like API, UBC, IS etc.…
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