Nearly no load bearing behaviour of reinforced concrete members allows such varied interpretations and complex discussions as the shear behaviour. Especially the three-dimensional problem of the punching shear failure of reinforced concrete members is internationally discussed. Nevertheless up to now, there is no unified design approach or even an overall accepted design model. Especially for large structural members, as they are commonly used in industrial structures and high-rise structures, the experimental background is missing.
Nonlinear analysis using Riks method is suitable for predicting buckling, post-buckling, or collapse of certain types of structures, materials, or loading conditions, where linear or eigenvalue method will become inadequate or incapable, especially when nonlinear material, such as plasticity, is present, or post-buckling behavior is of interest.
The use of expandable tubulars has emerged as a popular technology for drilling and completing wells. While expandable tubulars vary in type depending upon the application and specific well requirements, the most common approach is to actually form the metals downhole, which presents unprecedented challenges for tool designers. The costs and timelines to achieve a “workable” product can be tremendous.
Thermoelastic stress analysis (TSA) is a non-destructive method that is used to assess structural stress. It is based on the ability to measure stress induced thermal emissions during cyclic loading with an infrared camera. It has potential applications for the monitoring of wind turbine blades certification tests. In this work, conducted as part of the UK SuperGen Wind consortium, finite element (FE) analyses are conducted to evaluate the potential correlation with TSA outputs.
The purpose of the present work is to discuss some FEM procedures and experimental methods that are currently used in the pipeline industry and open the way to the possibility of developing new experimental apparatuses which can provide much more economical alternatives to traditional design codes and tests.
Expandable sand screens are a relatively novel sand control system, which are used to control the ingress of solids in oil and gas reservoirs with weak and unconsolidated formations. They combine the ease of installation of conventional screens with the borehole support of a gravel pack.
There are two different variations of expandable screens; a system based on a slotted basepipe which are easy to expand but relatively low in strength and a system based on a drilled basepipe which are very strong but difficult to expand.
Expandable sand screens are a sand control system, which is used to control the ingress of solids in oil and gas reservoirs with weak and unconsolidated formations. There are two different variations of expandable screens; a system based on a slotted basepipe which are easy to expand compliant to the formation but is relatively low in strength and a system based on a drilled basepipe which is very strong but is more difficult to expand compliantly. FEA has been used to model the slotted basepipe type to better understand the interaction of the expanded screen with the rock formations.
The development plan of a hydrocarbon field includes the design of all the production/injection wells forecasted for the scenario considered. The pressure depletion occurring during the hydrocarbon reservoir exploitation induces rock compaction in the near wellbore area, which may result in mechanical actions transmitted to the well completions, that alter the stress regime in some of their sections. This phenomenon can possibly bring to the failure of the casing and of the cement, eventually leading to the well shutdown and to significant economic loss.
As design cycle times are shortened, engineers continue to find ways to be more productive. Generally, one tries to leverage software tools to get solutions faster. This productivity improvement is possible through continued software advancements, such as the Pro/ENGINEER to Abaqus/CAE Associative Import, via an Elysium Neutral (Assembly) File. Engineers can iterate from CAD to FEA while retaining applied loads and boundary conditions. This paper will discuss use of the associative import features with design changes (such as thickness change, split surfaces, or holes).
In field operations, during rapid deceleration of pipe (simulated by drop-catch process) or slack-off stop process, significant dynamic effects can occur. The dynamic event can amplify the load on the pipe string, and the amplified load can break a weak thread. It is necessary to understand the mechanics of this dynamic event, and thus, provide guidelines or directions for safe design and operation of the pipe string. An analysis procedure using FEA, which involves fluid-pipe interaction, has been established for this study.
The use of Underground Gas Storage (UGS) is expected to increase considerably in the near future due to various factors. Many of the UGS wells require sand control. Expandable Sand Screens (ESS) have many advantages as a completion option in UGS wells. But there has always been a concern on the effects on ESS due to cyclic loading. The paper deals with the changes in the borehole that would be caused during annual injection and production cycles from the storage reservoir.
When simulating bolts, the amount of detail to include is often raised. The analyst is left with using judgment in deciding to include or not include details, such as threads. For system models, where the primary bolt function is to transfer load from the cover to the base, thread details are sometimes perceived as not needed. It is believed that a reasonable result can be achieved without this detail. Should the bolt head contact interface be bonded or full, and how does this affect the shank stress, is another concern. This again is a judgment left to the analyst.
Santos Basin is one of the most promising basins of Brazil, recently it was discovered light crude oil of 30º API (American Petroleum Institute), this reservoir of high productivity is located below a salt layer of two thousand meters of thickness. Salt also known as an evaporite rock is found in many hydrocarbon basins around the world. Evaporites are sediments formed initially from minerals dissolved in water, the most common are: halite, gypsum, and anhydrite. These minerals are found in areas that passed by a geological time of high evaporation or precipitation.
For the past few decades, with depletion of hydrocarbons in more readily accessible regions, petroleum operators have shown increasing interests in exploring onshore oil and gas reserves in Arctic areas, which are typically overlain by substantial permafrost layers on the order of 150 to 500 m thick. A key challenge to the completion of these wells is how to manage the impact of thaw subsidence of permafrost layers throughout expected well life.
Thermal technologies are widely used for the heavy oil recovery. The thermal processes usually consist of some variation of Cyclic Steam Stimulation (CSS), steam flood or Steam Assisted Gravity Drainage (SAGD). These thermal recovery applications have experienced numerous well casing failures around the world, often resulting in loss of wellbore integrity, lost production and added costs.
The Extended Finite Element Method (XFEM) capabilities of Abaqus V6.9-EF1 could have a significant impact on finite element modeling of failure for the U. S. Army. The Army has many areas where fracture is important from failure of components, to penetration, to warhead development. To assess the value of XFEM under static loading, comparisons were made with experimental data of notched panels. The panels had different angles of notches. The crack growth direction and applied forces for crack growth were compared to experiments using ABAQUS.
In developing weapon systems for the warfighter, the US Army uses modeling and simulation tools to support the design, test and manufacturing of these systems. One of these tools is Abaqus/Explicit, including the coupled Eulerian-Lagrangian capability CEL. The addition of CEL in version 6.7EF-1 opened the door to a new realm of problems that could not be previously be modeled. With the addition of this new capability came the need for internal validation to establish a level of confidence for the class of problems of interest to the U.S. Army.
Monte Carlo reliability calculations for high-reliability systems are very computationally expensive. Variance reduction techniques optimize this process greatly and directional simulation is one such technique. Directional simulation is particularly valuable for high reliability systems where the failure surface is highly curved or dislocated.
A new method is introduced for conducting blast load analyses using the new Coupled-Eulerian-Lagrangian (CEL) capability of Abaqus/Explicit. In the past, either a 1-D blast code or tabular data was used to determine a pressure vs. time curve that would be applied to the exterior surfaces that were assumed to interact with the blast wave. These pressure curves were generated using knowledge of the amount/type of explosive and line-of-sight distance away from the explosion.
A finite element model is developed to investigate the instantaneous as well as long-term (time-dependant) structural response of a pre-loaded torsional spring. Torsional springs belong to a class of spiral springs that are commonly made out of Elgiloy - an alloy of Cobalt, Chromium, Nickel and Iron. Elgiloy has very high yield strength, and is commonly used as a spring material in clocks.
The U.S. Army Armament Research, Development and Engineering Center (ARDEC) at Picatinny Arsenal, NJ is developing an inert 40mm sensor grenade which houses an array of sensors and electronic components. This grenade is intended to be fired from a hand held launcher and relay sensory information back to the user. To accomplish this task, the internal electronic components must be structurally housed and guarded from impact induced g-levels.
The Army is developing new grenades with sensors instead of explosives. A grid of 40-mm grenades will be fired from conventional M16 rifles. The projectiles must survive gun launch and impact. After impact, soldiers will get a real-time ‘picture’ of a local area. Signals from the onboard sensors will be processed on a hand-held computer that captures the activity within the
In a firearm the firing cycle is a high-speed dynamic event, of short duration (a few milliseconds) and highly non-linear - large displacements, plasticity, contact - during which its components are subjected to pulse loads - high-pressure and temperature gas and impact between moving parts. In the design of any firearm choosing the locking (breech) system is the fundamental starting point as this will guarantee that the cartridge case is adequately supported to withstand the tremendous rearward thrust exerted by the powder gases.