In Eurocode 3, the effective cross-sectional area (𝐴eff) is calculated by reducing the contributions of slender plate elements (e.g., flanges and webs) prone to local buckling, unlike the gross cross-sectional area (𝐴), which considers the entire section without reduction. For 𝐴eff, slender elements with width-to-thickness ratios exceeding critical limits are adjusted using a reduction factor (such as 𝜌) based on their slenderness and stress distribution, resulting in reduced effective widths (𝜌⋅𝑏). 𝐴eff is the sum of these reduced areas and any non-slender elements (Aeff =∑(ρ⋅b⋅t)+non-reduced areas where, ensuring only the load-bearing portion of the section is considered, while 𝐴 assumes the entire section contributes to resistance. b = width of the slender plate element t = thickness of the plate.

@@HITS2009 : Thank you my brother for your prompt reply and I appreciated! Your videos are very well thought and presented. They are some of the best videos that I have come across but I am very disppointed not watched by many. I forward the links to my friend to watch them. Keep up the good work and GOD bless you and "Happy New Year and Best Wishes for 2025"!

@@rahmanrahmani2896 Thanks a lot. I truly appreciate your support and for sharing my videos with your friends ; it means a lot. Please, feel free to ask.

The forces applied on welds are determined based on a frame or beam analysis permititng to assess the shear force and the normal force at the considered weld. You can see this link: kzbin.info/www/bejne/iJLFoZaBnqiheNE. Thanks for your interest.

You're welcome

Oui vous avez parfaitement raison. Merci.

Thanks a lot.

Ok sir, as soon as possible. Thank you very much indeed for your interest.

You are sir, i am not sir :D I am just a humble junior tank engineer from Egypt and I send you and all Tunisia my warm regards < 3 @@HITS2009

Thank you for your interest. The corrosion allowance is determined based on some factors, principally the construction material and the stored fluid properties, but also the operating conditions, the expected service life of the storage tank, the safety factors and the applicable standards, etc. Typical corrosion allowances can range from 1.5 mm to 6 mm for carbon steel storage tanks and sometimes as low as 1 mm or less for more resistant material to corrosion such as stainless steel. It is to not that corrosion allowance shoud be optimized under some economic consideratons and it should be, also, agreed by the customer. Please feel free to ask.

تفتح صمامات الأسطوانة ربع دورة وهذا كافي.

Thank you for your interest. First of all, it is to note clearly that the shell courses extend from the bottom of the tank to the top, where they meet the roof or cover of the tank. Thus, the height distance between the top of the "last" shell course and the beginnig of the roof is theoretically zero. But, please note that in the "last" shell course, the level of the stored fluid may not cover the whole height of the "last" shell course. The level of the stored fluid can be, for example, just one half or one third the height of the "last" shell course. It depends on the design liquid level of the stored fluid (imposed by an overfill slot governing the maximum capacity of the storage tank) with regard to the height of the storage tank between the bottom and the top of shell height where the roof begin. For further assimilating my answer, please see Figure 5-4-Storage Tank Volumes and Levels in API650.

Thanks Mr. Rashed , I appreciate your helping.

@@MUAADHMOHAMMEDMOHSENAL-QUSARI I am at your service. Do not hesitate to ask.

Bonjour. Merci pour votre interêt. Généralement sur une plieuse manuelle (plieuse universelle appelée aussi plieuse à sommier), la force de pliage est calculée en se basant sur la formule: F=L×E×R. Avec: F est la force de pliage en newtons (N); L est la longueur de la pièce à plier en mètres (m); E est l'épaisseur du matériau à plier en mètres (m); R est le facteur de résistance du matériau (voir les Tables de résistance des matériaux). Il est à noter ici que la formule ci-dessus est une simplification. En réalité, d'autres facteurs interviennent tels que le type d'outillage utilisé, forme de la pièce, ...etc. Pour aboutir à des résultats plus précis, il est judicieux de consulter les manuels fournits par le fabricant de la presse universelle considérée.

Than you very much indeed for your interest.

Thanks a lot for your interest. No, it is not an error. In fact, the negative sign arises due to the sign convention used in structural mechanics. It's a convention to consider positive curvature as being concave upward. In other words, if a plate is concave upward, the curvature is positive, and if it is concave downward, the curvature is negative. The negative sign in the equation ensures that the sign of curvature aligns with the direction of the bending moment in the plate. It makes the relationship consistent with the conventions used in structural engineering analysis and design. When you see the equation rx=-w''(x), it means that positive curvature corresponds to a concave upward deflection of the plate.

Thank you for your interest. You talk about a shell not a plate problem. The biharmonic equation is applicable to thin plates, the analysis of shell deflection typically involves more complex equations that account for the specific geometry and deformation characteristics of shells. The specific equations will depend on the assumptions and theories used for shell analysis, such as the Love-Kirchhoff theory for thin shells or other theories for thick shells. The basic equations for thin shells are derived from the equilibrium and compatibility conditions and are usually expressed as a system of coupled partial differential equations. The Love-Kirchhoff theory considers the first-order approximation of the shell's geometry and leads to equations involving the curvatures and membrane strains of the middle surface. The equations describe the balance of external and internal forces and moments, as well as the compatibility between deformations. I will work on an example about the shell elasticity in the next month.

@@HITS2009 Yes Shells indeed are interesting. That example would be great.

The size of the leg of the weld bead is determined out of the ASME code by the formula: L=T/cos(45°) with L=Leg of the weld of bead. T=Throat of the weld bead. You can see this link: www.mtm-inc.com/welding-basics-the-fillet-weld.html. The throat of the weld bead is determined based on the correct sizing of weld bead. You can see these educational videos at these links: kzbin.info/www/bejne/Zl68mGqJdtuKbNk and kzbin.info/www/bejne/hIDMg2qFmLN4odU. Thank you for your interest.

@@HITS2009 Thank you so much, i'm stuck here but you show me clearly!!!!

Thanks a lot. Very nice. If you have any questions do not hesitate to mention it in the comments.

Merci bien pour votre encouragement.

Thank you very much for your interest. I'll post an educational video about your request as soon as possible.