Stress Distribution at the Fillet of an Internal Flange

Stress Distribution at the Fillet of an Internal Flange
This paper deals with the determination of the stress distribution at the fillet of a ANSI B16.5 flanges attached internally to a hollow cylinder. A load parallel to the axis of the cylinder and of variable eccentricity acts on a bearing plate which rests on the flange. The strains are measured by means of electrical resistance wire strain gages. The ratios of the mean cylinder diameter to the cylinder wall thickness and of the mean cylinder diameter to the flange thickness are varied. The principal stresses at the fillet are given as functions of these parameters. The experimental results are compared with the stresses calculated on the basis of an approximate theoretical solution for both an axial and an eccentric load.
Abstract Joining of steel pipes and pipe flanges use today the conventional method of fusion welding, where the flange is girth-welded onto the pipe. However, fusion welding of flanges to pipes is associated with many disadvantages such as the final quality of the weld, degradation of the mechanical properties of the base pipe near the heat affected zone, defects and cracks appearing in the weld, misalignments, to mention a few. The current study proposes a novel pipe-flange connection to replace the fusion welding process of steel pipes with a method based on cold working. The method is based on that the steel pipe is inserted into the neck of the flange, in which two circumferential grooves are manufactured. An expansion tool having two teeth is entered from the open side of the connection and is expanded hydraulically such that the teeth deform the pipe and cold work it plastically into the grooves. This will provide a strong joint between the flange and pipe. In this study the performance of the connection is maximized by optimizing the design of the flange and the expansion tool.
The use of bolted flange connections in the offshore wind industry has steeply risen in the last few years. This trend is because of failings observed in other modes of joints such as grouted joints, coupled with enormous economic losses associated with such failures. As many aspects of bolted flange connections for the offshore wind industry are yet to be understood in full, the current study undertakes a comprehensive review of the lessons learned about bolted connections from a range of industries such as nuclear, aerospace, and onshore wind for application in offshore wind industry. Subsequently, the collected information could be used to effectively address and investigate ways to improve bolted flange connections in the offshore wind industry. As monopiles constitute an overwhelming majority of foundation types used in the current offshore wind market, this work focusses on large ANSI welding neck flanges in the primary load path of a wind turbine foundation, such as those typically found at the base of turbine towers, or at monopile to transition piece connections. Finally, a summary of issues associated with flanges as well as bolted connections is provided, and insights are recommended on the direction to be followed to address these concerns.
As per recent reports, the offshore wind sector could bring in £17.5 bn investment to the U.K. economy over the next few years after faster than expected cost-cutting slashed subsidies for the technology by half [1]. On top of that, the baseline scenario for the United Kingdom’s installations by the end of 2030 is to reach the capacity levels of 40 GW, four times the current state [2]. Additionally, the target of £100 per MWh set for the year 2020 regarding the levelised cost of energy (LCOE) of offshore wind was achieved in U.K. projects four years earlier in 2016 [3]. The above figures reinforce the need for new technological developments that will enable the utilisation of larger and more efficient offshore wind turbines (OWTs). In this direction, one of the most important concerns is the support structure of the turbine’s tower, which requires further study concerning not only the feasibility of future installations, but also current problems that need to be better understood and addressed.
OWT structures, which are quite large in thickness and diameter, operate in the hostile marine environment, where variable amplitude loads are constantly applied on different parts of the structure [4,5]. In the offshore industry, grouted connections were initially used to charge the transition piece (TP), with a certain overlap length, on the monopile (MP) foundations. Therefore, there is a tube-in-tube connection, wherein the space between the two tubes is filled with grout (Figure 1) [6]. Towards the end of last decade, numerous grouted connection joints between large diameter monopiles and connecting tubular steel transition pieces at the base of overlying support towers were found to be failing. For the majority of U.K. offshore MPs that experienced grout cracking and failures, the issue was recognised to be primarily owing to the widespread absence of shear keys (or weld beads) on straight MP and TP surfaces. Bending moments as a result of complex wind (which was the main difference in loading conditions compared with oil and gas platforms) and wave loading were important design considerations that were not accounted for during design of grouted connections for OWTs. Furthermore, axial connection capacity was found to be significantly lower than that assumed previously owing to the MP scale effect, lack of manufacturing and installation tolerances, and abrasive wear due to the sliding of contact surfaces when subjected to large moments. Typical failure modes included dis-bonding, cracking, wear, and compressive grout crushing failure.
The number of bolts depends on the ANSI plate flanges radius and thickness, type of tool used, size of the bolts, and predicted loads on the structure. These bolts serve the purpose of exerting a clamping force to keep the joint together [20]. The behaviour and life of the bolted joint depend on the magnitude and stability of that clamping force. The preload is created by the tightening process during the assembly of bolt and nut in the joint to provide enough clamping force on the joint. Therefore, the bolts need to be preloaded at the assembly stage in the flange connection. An intuitive analogy would be to think of the bolts and the joint members as elastic parts. In that way, they can be modelled as spring elements, where the bolts are stretched in their elastic region when tightened, in order to compress the joint. The joint has a much stiffer elastic constant compared with the bolts, depending on material and dimensions.
It is possible to consider the bolt as an energy storage device, which accumulates the necessary potential energy to clamp the joint and is subjected to several environmental and operative conditions that may affect its behaviour [20]. The objective is for the preload on the bolt to be maintained at a certain level, but, owing to a large number of influencing factors, it is almost impossible to achieve or retain the desired state. It must be noted though, that the main concern is not the value of preload on the bolt, but maintaining the sufficient level of clamping force that holds the joint together. Moreover, if the clamping force is too low, the joint could loosen and be subjected to more severe consequences owing to cyclic loads. On the other hand, if the bolt is over-tight, it could exceed its proof load and may break under external load. In fact, during the tightening process, a torque is applied to turn the nut and the bolt stretches. This operation creates preload in the bolted joint. This sequence of events, at any point, controls the preload. It is possible to control the preload through torque or turn or stretch or through a combination of all of them. In all of the control strategies, the torque is used to tighten the fastener even if other mechanisms are used to control the tightening. There are a lot of uncertainties in the relationship between the control parameters like torque and the preload, which could be minimised by measuring and controlling the build-up of bolt tension. This is the motivation for creating the family of tools called bolt tensioners. Using the bolt tensioner is nowadays a common practice during the installation of offshore wind turbines.
The employment of ANSI blind flanges connections for OWTs has considerably increased in the past decade owing to the failures and subsequent economic losses associated with grouted connections. In this study, the issues and opportunities associated with bolted flange connections have been thoroughly reviewed and discussed for application in the offshore wind industry. The key conclusions drawn from this study are as follows:
The advantages of bolted flange connections include the provision of direct load path through the primary steel alone, thereby avoiding slippage, reducing steel requirements compared with grouted connections, the absence of curing time, and easiness to inspect and monitor the MP–TP connection.
The challenges associated with bolted flange connections include material selection issues, short-term relaxation of bolts, issues associated with load distribution in threads, and static failure of bolted flange.
The main cause of short-term relaxation is the embedment that occurs mostly owing to surface irregularities as well as time-dependent creep deformation.
The consequence of temperature differential can either increase or decrease the clamping force depending on the thermal expansion and contraction coefficient of the materials employed in bolted connections.
The setups associated with bolted joint such as washers, lubricants, coatings, and gaskets play a pivotal role in creating and maintaining integrity in bolted joints.
The failure modes observed in bolted joints include self-loosening, fatigue failure, corrosion, and galling.
An expected trend in the bolted flange connection is the increased usage of tensioning tools compared with torqueing applications.
Further studies in the offshore wind industry can enable the optimal use of ANSI threaded flanges connections in design, manufacturing, installation, operation, maintenance, and decommissioning phases.
Ring flange connections for tubular towers, like those for wind turbines or chimneys, are subjected to significant fatigue loading. Next to the bolts, the weld connecting the flange to the tower shell also needs to be checked against fatigue failure. The flange causes local bending moments in the shell, which increase the meridional stress, i. e. stress concentrations occur. In this paper, the influence of geometrical imperfections on such stress concentrations is quantified and the influence of flange geometry on resulting stress is investigated. Recommendations are given for flange dimensions and the design procedure.

internal anchor links no longer working after upgrade

here is my website you can see the main button on the top, when mouse hover browser says it anchor to #port but when I click nothing happened. This happened after multiple WordPress upgrades (I didn’t check how the previous versions behaved).

Happen with plan text as well.

Any help would be appreciated

Best way to add onclick function to all internal links using javascript

As part of a plugin, I am looping all <a> link tags on a page and adding an onclick attribute.

But I only want to add the onclick attribute IF the link URL is on the same site… So I am using the siteurl option value as part of this detection. (Also, I I realize I could add a click event listener instead… I’m not sure if there is any advantage to that approach.)

Here is what I have so far (extracted and simplified to make it easier to read):

var siteurl = '<?php echo get_option("siteurl"); ?>'; var ignoreclasses = [ 'external' ];  alinks = document.getElementsByTagName('a'); for (var i = 0; i < alinks.length; i++) {     if ( !alinks[i].onclick && !alinks[i].getAttribute('onclick') && (alinks[i].href != '')       && !alinks[i].getAttribute('target') && (alinks[i].href.indexOf('javascript:') !== 0) ) {         skip = false;         if (ignoreclasses.length) {             for (i in ignoreclasses) {                 if (alinks[i].classList.contains(ignoreclasses[i])) {skip = true;}             }         }         if (!skip) {             external = is_link_external(alinks[i]);             if (!external) {alinks[i].setAttribute('onclick', 'return my_function(this);');}         }     } }  function is_link_external(el) {     /* treat hash or query as internal */     u = el.href; a = '#'; b = '?';     if ((u.indexOf(a) === 0) || (u.indexOf(b) === 0)) {return false;}      /* check against site URL */     if ((siteurl != '') && (u.indexOf(siteurl) === 0)) {return false;}      /* check against host/protocol */     if ( == {         a = window.location.protocol+'//';         b = '//';         if ((u.indexOf(a) === 0) || (u.indexOf(b) === 0)) {return false;}     }     return true; } 

So that is what I have so far and it seems to be working well, my question is, am I missing anything? Are there any weird URLs that fall outside of this scope that I haven’t thought of? Or maybe there are other edge cases or some possibility that could trigger an error somewhere. I just want this code to be as robust as possible.

Funny Viral Video Site Like Youtube with Internal Ads System LMAO Video!

If you have a social following, you could make a lot of money with this site. Accepted by Adsense and includes internal ads system for users to buy ads. Everyone loves funny videos, upload and share!

Amazing domain name and website offering funny videos that both admin and visitors can upload to populate the site. Admin panel full of features to help you build a massive collection of funny videos that people will share on social…

Funny Viral Video Site Like Youtube with Internal Ads System LMAO Video!

Is it possible and how to log a website internal connection activity?

For instance, I have developed a WordPress website and prepared to deploy to client’s server. Since they request the site to be scanned in their VPN server first. For some reason, the application connects to many external resources and because the VPN is blocked the site from connecting to other location than its internal address, it is very slow. The slowness is believed to be due to blocking and retrial until giving up.

Since the application consists of a lot of plugins. What connection it is trying to make is not so obvious and straightforward.

Is it possible to track/log what the connection it is trying to made? If it is possible, I could do it in local server environment level and coding level to make a list of connection that it is trying to connect. And then I could use this list to discuss with the client and ask for white listing.

eg. normal connection log /user activity utility could log user A with IP A visit > website.

But currently, if the site itself connect to

  • <<< possible log it down?
  • website B …
  • website C

Any hints, suggestions, insight is highly appreciated. Thanks a lot.

Using Anchor Links aka Jump To Links with Internal Linking Strategy

Do anchor links that link to another page help or hurt SEO internal linking strategy?

For example, let’s say I have two pages:, and

And, on /subtopic-service I have anchor links like:

And, I link to that anchor like from the higher level page /services.

I know that anchor links aren’t indexed. But, will I get the same SEO benefit from an internal link with an anchor link?

Problem of URLs with internal links with ‘base href’

I’ve got a website with includes the following directive in the HEAD section:

<base href="" /> 

Now, I want to create internal links to sections within the page ‘’

<a href="#photos">Photos</a> 

But, instead of linking to ‘’, it links to ‘’.

Any tip to fix this? Thank you.

Do bonus actions trigger the save from an Internal Injury?

One of the possible injuries from the optional "Lingering Injuries" table in the DMG is Internal Injury:

Internal Injury. Whenever you attempt an action in combat, you must make a DC 15 Constitution saving throw. On a failed save, you lose your action and can’t use reactions until the start of your next turn. The injury heals if you receive magical healing or if you spend ten days doing nothing but resting.

When suffering from an Internal Injury, do you have to make this saving throw when attempting a bonus action in combat, or just when attempting normal actions?

What’s the internal language of the opposite of a Cartesian closed category?

I have heard the simply typed lambda calculus is the internal language of Cartesian closed categories.

What’s the internal language of the opposite type of category?

I have the intuition the opposite category would correspond to continuation passing style or pattern matching but the opposite typing rules seem very strange and hard to figure out.