Finite Element Analysis for Pipeline Leak Containment System

Offshore pipeline on-bottom roughness analysis is generally performed to understand pipe stress and areas of free spanning. In this paper, the predicted pipeline profiles, by finite element analysis (FEA) modeling, are compared with survey data. Several case studies are presented and parametric effects are assessed. The FEA modeling procedures are presented in this paper along with several project experiences. The pipeline on-bottom roughness analysis is conducted to determine the pipe stress and the associated fatigue damage due to internal pressure and temperature fluctuation and vortex-induced vibration (VIV) of free span sections due to seabed unevenness. The analysis presented in this paper can aid the design of pipeline free spans and mitigation, if required. The parametric effects of higher and lower bound soil stiffness, friction resistance, pipeline bottom tension, external / internal pressure, and content density are considered. The predicted pipeline profiles by FEA modeling are compared with surveyed profiles under several loading conditions. A strong correlation between survey data and finite element analysis (FEA) is achieved. This paper shows that the FEA stress prediction is adequate, and the FEA modeling is suitable as an advanced design tool for pipeline on-bottom roughness assessment and free span behavior analysis. A commonly used mitigation method for VIV fatigue is to install VIV suppression strakes. For overstresses due to pipeline bending effect, the common mitigation methods are to install mechanical supports, use heavy wall pipe and correct the seabed unevenness among others. It is important to reliably predict the pipeline profiles in order to precisely assess the pipeline free span response and to provide guidance to determine a proper free span mitigation strategy. The FEA method can be utilized to realistically simulate the pipeline on-bottom roughness behavior affected by the pipe properties, pipe-soil interaction including penetration and soil friction resistance, the internal and external pressure, product content, temperature profile, and the bottom tension from pipe-lay. An accurately built FEA model can provide a reliable prediction for the pipeline profile, free spanning length and gap under all conditions, which are crucial for the stress and fatigue assessment as well as for the design of free span mitigation.

To establish a 3D finite element model of normal knee joint involved its meniscus, which can be used to simulate the anatomical morphology and characteristics of human knee joint, to verify the validity of the model by preliminary FEA mechanical analysis, and explain partially biomechanical mechanisms of meniscus. CT and MRI data were harvested by scanning the knee joint of a healthy male volunteer, and then these data were imported into Mimics 10.01 software and Geomagic Studio software to constructed the 3D models of tissue structures of knee joint. These models were combined to constructed the 3D model of intact knee joint and meshed in ANSA software. Therefore the finite element model of intact knee joint was established. Finally, after the definitionof its material behavior, boundary conditions and loading. The finite element model of knee joint was analyzed and verified using ANSYS software. Meanwhile The biomechanical properties of meniscus were analyzed. The complete knee finite element model composed of bone, meniscus, articular cartilage, and major ligaments was established. It could effectively simulate the anatomical morphology and characteristics of knee joint and its meniscus. The contact area of medial meniscus was 771.05 mm2, while the contact area of lateral meniscus was 634.31 mm2, and the ratio was 1.216. The stress distribution was uniform, but the stress of the medial meniscus was higher than that of the lateral meniscus, and the peak stress located in the posterior horn of the medial meniscus and the anterior horn of the lateral meniscus, respectively, and the peak stress value was 4.11 MPa. The maximum displacement of the meniscus was located in body, and the displacement of the medial meniscus was more remarkable than that of the lateral meniscus, and the maximum displacement value is 0.33 mm. The obtained finite element analysis results corresponded to that reported in the literature, which mean the model's reliability. The established finite element model of knee joint are proved to be have validity, and is a useful model for finite element analysis of meniscus tear and menisectomy. The results of finite element analysis can explain partially biomechanical mechanisms of meniscus which can provide theoretical guidance for clinical treatment of meniscus injury.

Regression modeling and prediction of road sweeping brush load characteristics from finite element analysis and experimental results

Finite element simulation analysis was carried out on the seismic performance of the joint test specimens of built-in section steel assembled concrete shear wall. A finite element analysis model is established, and referring to specifications and existing research results, the definition of constitutive relation properties of concrete, section steel, steel bar and other materials is emphatically elaborated, in which the damage model is introduced to simulate the damage characteristics of concrete materials under low-cycle repeated action. After obtaining the cloud diagram and hysteretic curve of strain, stress, deformation and structural damage of the finite element test results, the differences between the finite element analysis and the experimental study are compared, it is found that the structural damage is obvious and the pinch effect of hysteretic curve reflects the characteristics of flexural-shear failure. Comparing the results of finite element analysis with the experimental results, the finite element analysis model can simulate the test conditions well, and basically embody the process of stress, strain, displacement, damage and failure characteristics of the specimens.

Seismic performance of a square HSS column to H-section beam bolted connection with double cover plate

High magnetic field strength and high-speed gradient coil current switching are becoming ever more commonplace in magnetic resonance imaging scanners. These and other factors are combining to yield high acoustic sound pressure levels (SPLs) in and around magnetic resonance imagers. Studies have already been conducted which partially characterize this sound field, and various methods have been investigated to attenuate the noise generated. In order to predict the vibration and acoustic response of a gradient coil inside a scanner, finite element analysis (FEA) was carried out. The model was based on specific internal and external structural dimensions and the material physical properties of a gradient coil. The FEA results were verified through experimental modal testing of the same gradient coil. It was found that the experimental modal analysis results were in good agreement with the FEA results. The Lorentz force distribution on the gradient coil caused by the time varying current in the coil windings was then applied to the FEA model to obtain the velocity distribution of the coil surface as a function of time. A vibro-acoustic computational model was then developed based on the verified FEA model. The surface velocity distribution was then used to predict the sound field inside the gradient coil. The vibro-acoustic model was verified using experimental noise measurements with swept sinusoidal waveform inputs to the gradient coil conductors. The numerical methods developed in this study could provide a guide and virtual testing platform for the designer of gradient coils to predict the vibration and acoustic behavior of new designs and thereby offer the opportunity to redesign and/or optimize the design to reduce SPLs.

Experimental results for photothermal lens measurements are compared to finite elemental analysis models for commercial colored glass filters. Finite elemental analysis software is used to model the photothermal effect by simulating the coupling of heat both within the sample and out to the surroundings. Modeling shows that heat transfer between the glass surface and the air coupling fluid has a significant effect on the predicted time-dependent photothermal lens signals. For comparison with experimental signals, a simple equation based on the finite element analysis result is proposed for accounting for the variance of experimental data where this type of heat coupling situation occurs. The colored glass filters are found to have positive thermo-optical coefficients. The net positive dn/dT of CdSxSe(1-x) doped glass filters is considered to be the consequence of counteracting factors: optical nonlinearity, stress-induced birefringence, and the structural network of glass. Finite element analysis modeling results are also used to correlate experimental measurements of different sample geometries. In particular, the glass samples are compared to ethanol solutions of iron (II) dicylopentadiene in a sample cuvette even though heat transfer is different for these two samples.

Fiber reinforced polymer (FRP) strengthening has been widely used for concrete structures. However, limited studies have been conducted on its application to steel structures. The use of FRP materials to retrofit steel members is an effective replacement for welded or bolted steel plates and offer high strength-to-weight ratio, resilience to environmental degradation, and a robust fatigue performance. Past studies have shown that the application of FRP to steel is a promising technical solution to help against corrosion and also to increase the load carrying capacity of steel members. In the present study, finite element analysis (FEA) model of a steel beam strengthened with carbon fiber reinforced polymer (CFRP) laminates was developed using ANSYS Mechanical finite element software program. The model was validated by comparing the FEA and experimental results of an existing study in the literature and they were in good agreement. A parametric study was conducted on the validated steel beam model with the aim to investigate the effects of basalt fiber reinforced polymer (BFRP) and two types of adhesives on its performance under static loading. The FRP laminates provided an increase in flexural capacity and pseudo ductility of the beams. The optimum bond length was found to be 2/5 of the span length for the beam in this study.

3D-printing induced defects are intrinsic to the layer-by-layer deposition process, which results in reduced performance of materials fabricated using extrusion-based additive manufacturing (AM) techniques. In this study, the effect of porosity introduced by fused deposition modeling (FDM) AM technique on the mechanical performance of natural carbon-enhanced polymer composite (NCPC) materials was evaluated experimentally and through finite element analysis (FEA). Computed Tomography (CT) scans of 3D-printed and traditionally fabricated specimens were used to evaluate porosity and generate the mesh for the FEA model. The FEA results showed that a porosity level of 5.6% led to a reduction in ultimate tensile strength (UTS) and flexural strength (FS) by approximately 6%, compared to a non-porous FEA model. However, the experimental 3D-printed samples showed a 7% lower UTS and 39% lower FS compared to the FEA porous model. As expected, the injection-molded NCPC materials outperformed the compression-molded and 3D-printed samples for both experimental and FEA results.

<div class="section abstract"><div class="htmlview paragraph">“The purpose of this study is to explore the structural behavior of motorcycle frames that are fabricated from metals such as steel and aluminum, and that are welded together to generate beams. The components of the wheel, handlebar, and saddle are assembled together to form the chassis of the bicycle. For the purpose of determining modal characteristics such natural frequencies and mode shapes, two different analytical approaches, namely finite element analysis (FEA) and experimental modal analysis (EMA), were utilized. The framework of the chassis was design in 3D using CAD software to carry out the FEA, and after specifying the meshing type and material parameters, normal mode analysis was carried out. To contrast modal characteristics with FEA results, EMA utilized impact hammer testing with a roving accelerometer approach. The study discovered differences between the two methods, which were effectively minimized to less than 10% by carrying out a model, update technique to increase the FEA model's precision. According to the results, model updating can help reduce differences between EMA and FEA and increase the accuracy of FEA models that are impacted by modeling difficulties and predictions of material characteristics.</div></div>

Most wellbore strengthening (WBS) techniques require an understanding of the width on an induced fracture to design the size and concentration of appropriate mud additives to mitigate the fracture growth. Current methods to estimate fracture width primarily consider stress and rock properties but neglect the effect of the thermal contrast between the drilling fluid and the formation. This paper reports the results of the modeling of the thermal effect on fracture width and proposes a practical method to integrate the thermal effect into current WBS design workflows. The proposed process uses both analytical and numerical methods to investigate the thermal effect. A finite element analysis (FEA) model simulates the coupled stress and temperature field around the borehole, which allows the width of the fracture to be derived at any point along the length. The Abaqus FEA model uses 2-D plane strain elements to allow either steady-state or transient thermal-mechanical analysis. The results of FEA modeling are compared to the semi-analytical solution which only addresses the mechanical effect. Both models use field data to verify and validate results. An equivalent tensile stress is used to derive an analytical solution for fracture width for the case of ‘long-term’ cooling. The results provide a good match to the steady-state thermal elastic FEA results. In the case of transient heat transfer, an approximate analytical solution is derived to describe temperature distribution around the borehole as function of time. Then the analytical solution for thermal stresses is derived based on intact circular borehole. The analytical results are compared and verified with the FEA. Currently, the fracture width in response to a transient thermal event can only be calculated using the FEA model. The change in fracture width due to the temperature disturbance can be superimposed over the elastic fracture width to provide a more accurate estimate of width due to both mechanical and thermal influences for planning WBS formulations. The model demonstrates that the cooling of the borehole with drilling mud results in a wider fracture than that which is predicted by the purely elastic models. If drilling mud temperature is not considered or managed effectively, the failure of the WBS application could result, leading to a lost circulation event. A field case where wellbore cooling occurs and leads to lost circulation is presented.

This work is a vital step in enhancing the potential use of a newly developed organic basalt fibre reinforced polymer (BFRP) bars for prestressed concrete applications. In the present study, a test setup has been designed using finite element analysis (FEA) and the various steps of prestressing such as initial prestress, effective prestress and the time dependent effects have been appropriately simulated in the finite element (FE) model. The configuration details of the test setup, such as the size and orientation of the sections and the location of the stiffener plates have been thoroughly investigated. A robust design of the setup has been established based on the FEA results. Subsequently, the FE model has been utilized to predict the transfer stage parameters for concrete beams prestressed using BFRP bars.The transfer length has been predicted from the FEA results to be 24db and 26db (where, db is the diameter of bar) when measured using the BFRP bar strains and the concrete strains, respectively. An end slip of 0.3mm has been obtained after the prestressing of concrete beams. The designed test setup will be later fabricated and utilized to perform experiments under laboratory-controlled conditions.

IntroductionGeometrical designs of nickel-titanium (NiTi) rotary instruments have a considerable influence on their mechanical performance, and thereby have the tendency to fracture.AimTo evaluate the effect of cross-sectional geometry, pitch, taper, and off-center cross-section on the stress distribution in NiTi instruments under bending and torsion conditions using finite element analysis (FEA).Materials and methodsEleven theoretical three-dimensional finite element (FE) models of rotary instruments were constructed and divided according to the geometric design tested into; group 1 (cross-section geometry): four FE models with four different cross-section designs (triangle, convex triangular, parallelogram, and rectangle). Group 2 (pitch): three FE models with different pitches (5, 10, and 15 threads). Group 3 (taper): two FEA models with two different tapers (0.04 and 0.06). Group 4 (centering): two FEA models (off-centered and centered cross section). The behavior of the instrument under bending and torsional conditions was analyzed mathematically in SolidWorks software package.ResultsThe pattern of stress distribution was varied by altering cross-sectional geometry, pitch, taper, and off-center cross section.ConclusionNo single geometrical design could be beneficial for all stress conditions. To decrease the stress accumulation during bending of rotary files in curved root canals, the rotary NiTi instruments should be designed with rectangle cross-section configuration, low pitch, reduced taper, and with centered cross section. This design improved the flexibility of rotary NiTi instruments. However, to improve the torsional resistance during root canal preparation of narrow canals, the file should be designed with parallelogram cross-sectional configuration, low pitch, increased taper, and eccentric cross-section design.

This study was considered to occur the local wall thinning at elbow which is flowing the steam and high-pressure water of high-temperature. The angle of elbow is <TEX>${\Theta}=45^{\circ}$</TEX> and <TEX>$67.545^{\circ}$</TEX>. The damage behaviors of inner or outer wall thinning elbow under internal pressure were calculated by FEA(finite element analysis). We compared the simulated results by FEA with experimental data. The FEA results are as follows: In the FEA results of three types of wall thinning ratio, the circumferential and longitudinal stresses show the similar values regardless of the angle of elbow, respectively. The circumferential strain was greater at elbow of small angle, but the longitudinal strain was nearly same. The FEM stress of outer wall thinning elbow was slightly higher than that of the inner wall thinning elbow, and strain was also slightly higher. In the experiments, the circumferential strain was increased with the increase in the internal pressure, and increased rapidly on about 0.2% of strain. The longitudinal strain was small. The strain at break was much smaller than 0.2%. In the relation between pressure and eroded ratio, the criteria that can be used safely under operating pressure and design pressure were obtained. The results of FEA were in relatively good agreement with those of the experiment.

Three-dimensional (3D) outside diameter (OD) and wall thickness mapping of a casing joint include synchronized OD laser scanning and wall UT (ultrasonic testing) measurement at a resolution of every 1-inch along the length and every 1 or 2 degrees around the circumference. This full-length mapping data can then be used to construct a 3D finite element analysis (FEA) model that captures the geometric attributes, including OD, wall thickness, OD ovality, and wall eccentricity of a casing joint. Together with the actual nonlinear material plasticity model and the measured residual stress, the 3D FEA model can accurately predict the casing collapse strength. Also, the Klever-Tamano ultimate limit-state (KT ULS) collapse equation per API TR 5C3 [1] together with a calibrated moving-average scheme was used to calculate the joint's collapse strength. Results predicted by 3D FEA and KT ULS collapse models were then compared to the actual full-scale collapse test results. A 3D FEA model generally produces more accurate results than the KT collapse equation. In addition, both 3D FEA and KT collapse models predict slightly lower than actual collapse pressure, which therefore is on the conservative side. The accurate prediction of casing collapse strength can be beneficial to the end user in sorting and ranking the casing joints by collapse resistance, and therefore provides valuable information that can be used in the end user's risk assessment with the consideration of the worst-case discharge scenario. Furthermore, the end user may potentially select the joints with the highest predicted collapse strength for the bottom portion of the casing string where the highest collapse resistance is desired. In addition, the OD and wall mapping data together with the actual material tensile properties (yield strength, ultimate tensile strength, and strain hardening parameters) can be used in estimating the internal yield and ductile rupture pressures and other performance properties. This is outside the scope of this paper and can be pursued in future work. These predicted casing performance properties may then be used in sorting and ranking the joints based on a specific performance property of interest or combination of performance properties.