Double Bar Research Articles

Modeling and thermal property of multi-layer warp knitted spacer fabrics

With its unique three-dimensional structure, high porosity, and lightweight, warp-knitted spacer fabric (WKSF) is an excellent insulation material. Multilayer fabric is an effective solution for better heat control, meeting the different requirements of a wide range of applications in the field of temperature control. To know the relationship between structural parameters and heat conductivity, this study highlighted the heat transfer mechanism of multilayer WKSFs. Experimental WKSF samples were fabricated in a double needle bar warp knitting machine and had mesh and plain side layers, different thicknesses of 3 mm, 4 mm, and 4.7 mm. These samples were grouped into multilayer systems by changing thickness and contacting modes between two samples. Experimental results show that the number of layers and the type of contact between the layers affects the internal thermal convection of the multilayer system and thus has a significant effect on its thermal resistance. Also, the WKSF thickness plays a role in the thermal resistance of the multilayer system. To further clarify the heat conducting behavior from a microscopic perspective, a geometry model of multilayer WKSFs and transfer of heat physical field was constructed to perform finite element simulation by ANSYS. By comparing the simulation results with the test results, the established simulation model was practical and it was found that the heat transfer paths of multilayer WKSFs were affected by the distribution of media with different thermal conductivities. The research provides a theoretical reference for studies on thermal insulation materials.

Covalent organic framework/layered double hydroxide composite-coated poly(ether ether ketone) jacket for stir bar sorptive extraction of Sudan dyes.

A novel coating for stir bar sorptive extraction was developed by growing a covalent organic framework, TpPa-1 (derived from phenylenediamine and 1,3,5-trimethylphloroglucinol), onto the surface of Ni-Al layered double hydroxide. Using a poly(ether ether ketone) tube as the supporting substrate, a TpPa-1/layered double hydroxide-coated stir bar was fabricated and demonstrated excellent extraction performance for Sudan dyes. Notably, its extraction efficiency significantly exceeded that of stir bars modified with only TpPa-1 or Ni-Al layered double hydroxide. Based on this innovative coating, a stir bar sorptive extraction-high performance liquid chromatography method was established. This method exhibited low limits of detection (0.04-0.08ng/mL) for the analysis of Sudan dyes. It also featured a wide linear range (0.25-100 or 200ng/mL) and demonstrated good repeatability with relative standard deviations ≤6.22%. The recoveries obtained for spiked lake water and chili powder samples were 93.5%-105.2% and 87.8%-100.6%, respectively, demonstrating the practical potential of the developed method for detecting trace Sudan dyes in real samples.

Compression behavior of warp-knitted spacer fabric based on simplified finite element method

Warp-knitted spacer fabrics (WKSF), with their unique structure and excellent energy absorption properties, are widely utilized in the automotive industry, medical field, and aerospace sectors. However, during practical applications, WKSF undergo repeated compression, which can lead to compressive fatigue of the spacer yarns and consequently cause the WKSF to undergo irreversible deformation, which subsequently affects its performance and appearance. Therefore, to enhance the compressive properties of WKSF and investigate the mechanisms of plastic failure, this study used a warp knitting double needle bar raschel machine to fabricate a WKSF with a thickness of 20 mm. Through fabric structure analysis, we developed a unit cell model consisting of 32 fibers and a more comprehensive analysis model with 320 fibers to quantitatively assess the geometric changes of the WKSF during the compression process. Furthermore, we experimentally studied the performance changes of the WKSF under different compression speeds, various compression strains, and 1000 cycles of loading. By integrating experimental test with the finite element method, we have conducted an in-depth study of the compression process of WKSF, simulating the displacement U, Von Mises stress distribution, and plastic compression failure behavior during compression. By comparing data on Von Mises stress, equivalent plastic strain (PEEQ), and energy density distribution (SENER), we can clearly observe the performance of spacer yarns under compression conditions, providing significant insights into the underlying plastic failure mechanisms of WKSF’s. This study not only enriches the theoretical framework for WKSF compression but also lays a solid foundation for improving its performance and extending its applications.

A new tidal scenario for double bar formation

ABSTRACT Double bars make up a significant fraction of barred galaxies. We propose a new formation scenario for double bars that involves tidal interactions. We demonstrate the viability of this scenario using two examples of simulated galaxies from run TNG50-1 of the IllustrisTNG project. In the proposed scenario the inner bar forms first, either in isolation, via instabilities, or through previous tides. The outer bar forms later from the material that is tidally distorted by a strong interaction. The inner and outer bars formed this way rotate with different pattern speeds and can be mistaken for a single bar when their phases align. The double-barred structure is stable and can last for at least 3 Gyr. The inner bars of the tidally induced double bars can also have big sizes, which can possibly explain the origin of sizable inner bars recently found in some galaxies.

Heterogeneity of patients phenotyped as heart failure with mildly reduced ejection fraction

Abstract Background Current phenotyping of heart failure (HF) is based on the ejection fraction (EF) criterion, resulting into three types including the mildly reduced (mr) category. Little is known about the heterogeneity of the volumetric (ie left ventricular [LV] size) and clinical characteristics (including myocardial oxygen consumption, MVO2) of patients who are assigned to the HFmrEF class. Method The metric EF combines details on end-systolic volume index (ESVi) and end-diastolic volume index (EDVi). Both volumetric measures can be presented in the volume regulation graph (VRG), allowing the graphical inspection of the behavior of EF under a variety of conditions, with stratification options based on age, sex or other clinically relevant determinants. To overcome the limitations intrinsic to ratio-based metrics such as EF, we introduced a logical EF-companion (EFCi), defined as the square root of (ESVi² + EDVi²). In other studies the EFCi has been shown to offer incremental value beyond the single use of EF. Patients LV volumes were determined by biplane angiocardiography in 190 HF patients (69 women), and retrospectively analyzed. Results Average ESVi values for mrEF are 57.9 and 60.2 mL/m² for men (n = 22) and women (n = 10), respectively. The distribution of {EDVi, ESVi} data pairs in the VRG is shown in Figure 1, stratified for women and men. Patients categorized as HFmrEF are indicated by separate markers, and located in the region between the lines that indicate the 40 and 50% limits for EF. The double arrowed yellow bar refers to the wide ESVi range (27 to 118 mL/m²) for the patients within this narrow EF bandwidth. As ESVi refers to the extent of (reverse) remodeling and is associated with MVO2, there is a clear need the consider ESVi or EFCi for patients, in addition to their nearly similar EF values. Figure 2 shows the distribution of EFCi (range 59.5 to 231.8 mL/m2) for all HFmrEF patients, and clearly illustrates the supplementary value of the companion to the ratio-based metric EF. Conclusions As the bandwidth for EF narrows, the specificity of EF decreases and the higher the need to rely on EFCi. Thus, in contrast to the current view indicating that HFmrEF patients form a well-defined rather homogeneous phenotype exhibiting comparable clinically relevant characteristics, we found a relatively pronounced heterogeneity within the HFmrEF phenotype group. Distinguishing individual patients within the HFmrEF phenotype can be realized by considering the newly introduced parameter EFCi. This approach resolves most of the criticism thus far expressed regarding limitations of EF. The proposed additional dimension beyond EF offers a more comprehensive description of these patients, and will allow a personalized analysis based on a more careful characterization. Further investigations are warranted to explore implications for patient management.Figure 1.VRG for HF patients (n = 190)Figure 2.HFmrEF vs EFCi (n = 32)

Growth faults and avalanches: Reconstructing Paleoarchean basins in the Pilbara and Kaapvaal cratons

Four new volcano-sedimentary complexes (VSC's), respectively c. 3510, 3460, 3430, and 3320 Ma old, are identified in the East Strelley, Coongan, and Kelly belts of the East Pilbara craton and compared with the extraordinarily complete c. 3450 Ma Buck Reef-VSC in the southern African Kaapvaal craton. The VSC’s reveal an intricate relationship between volcanic deposition, sedimentation, development of syndepositional fault arrays, both extensional and contractional, and magmatism. The geometry and kinematics of these fault systems were analyzed after restoring the tilt of the stratigraphic sequences back to the depositional horizontal. The growth fault arrays are interpreted to have been generated by lack of lateral support of depositional basin margin prisms as known from present-day deltas and passive margins. This ‘basin margin collapse’ scenario for deformation and kinematics of the topmost section of the crust relies on topographic relief combined with vertical crustal oscillation. The relationship between supracrustal collapse and coeval deformation on deeper-seated detachments within the basement of the Pilbara remains as yet unsolved.The restoration corroborates the (semi-)circular basin architecture we proposed in 2017, which preceded, and is unrelated to, the present-day configuration of granitoid complexes and greenstone belts. The new findings also assess an early, syndepositional presence of the east–west Warrawoona Lineament as a major dividing line of as yet unknown structural character between two areas of basin superposition.For the Coonterunah Subgroup a multistorey architecture is established: the Table Top/Coucal-VSC with its near-water level chert top is overlain by regularly bedded Double Bar Basalt. The ensemble is truncated by the newly introduced tectono-stratigraphic Bergamina Unit, interpreted as a mega-avalanche emplaced somewhere between 3496 and 3466 Ma, possibly time-equivalent to the Duffer Fm.The crustal depths of the detachments below the (water-level) tops of all VSC’s identified, in other words the thicknesses of the VSC’s, are used as proxy for determining minimum basin centre depths ranging from 1000 to 3800 m. The greatest depth was reached in the North and South Coongan Basins, where voluminous bimodal volcanism of the Duffer Fm, maximum subsidence and deposition rates resulted in maximum basin margin instability.

Piezo-driven clamp release for synchronisation and timing of combined direct-shear stress waves

We propose a novel double clamp Tension-Torsion Hopkinson bar (TTHB) technique for measuring material responses under combined direct-shear loading. The proposed method overcomes the limitations of the existing high rate loading techniques by allowing arbitrary loading paths of tension and torsion to be prescribed to the specimen.High speed piezo actuators were employed to enable the synchronisation of direct stress and shear stress waves. The system also allows flexibility of control on the arrival times of torsional and tensile waves, thus enabling the generation of different dynamic loading paths. Direct and shear stress pulses can be generated such a way to achieve synchronised loading, torsion loading followed by tensile loading, and vice versa.The stress pulse histories of three different loading paths are presented to illustrate and validate the technique.

Flexural performance of a fully-prefabricated concrete slab with double-grouted sleeve connectors: An experimental and theoretical study

A novel fully-prefabricated concrete slab linked using double-grouted sleeve connectors is proposed to avoid projecting rebar and in-situ concrete, reduce linking length, and accelerate construction. This paper provides a systematic experimental investigation on the flexural performance of fully-prefabricated slabs under four-point bending. A total of four prefabricated specimens were tested with various diameters of the bottom transition and gap bars, and one cast-in-situ specimen served as a comparison. The results showed that the double sleeve connectors and gap bars in the slabs performed satisfactorily, and the load-bearing capacity of the proposed slab was very close to that of the control counterpart. The precast slab showed 19.1% and 42.8% increases in yield load-bearing capacity and 9.0% and 22.4% increases in ultimate load-bearing capacity, respectively, as the bottom gap rebar diameter increased by 4 mm and 8 mm. The cracking load of the precast slab was 30.0% smaller than that of the control slab, whereas all the cracks did not cross the interface between the grouting mortar and prefabricated part. Altering the linking bar diameter had a significant impact on the deformation shape of the slab. Increasing the bottom transition or gap bar diameter can significantly improve the deflection control capability of the slab. Theoretical calculations are conducted to predict the cracking load, load-bearing capacity, and deflection of the proposed slab, the predictions of which are found to agree satisfactorily with experimental data and can be applied to practical engineering design.

Coupled coastal monitoring framework for the analysis of beach stability and nearshore hydrodynamics of a structure influenced medium energy coast in India

This study presents a Coupled Coastal Monitoring Framework (CCMF) that integrates remote sensing (CoastSat), video beach monitoring system (VBMS), and numerical modelling to analyse the morphology and hydrodynamics of a structure-influenced beach. A 10.2 km stretch of straight beach with an artificial breakwater along the Kozhikode coast of Kerala, India, is selected for the study. The shoreline change analysis revealed that 38% of the total coast is under erosion, with the northern sector of the breakwater being highly erosive and the southern sector being stable. Continuous monitoring from the VBMS confirmed the stability of the southern sector with varying erosion accretion trends during 2018–21. Coastal morphological features such as double bars, cusps, and rip-like formations were identified through the VBMS, validated and analysed in detail with distinct wave-current interactions and sediment transport through numerical modelling. The study concludes that the breakwater is effectively protecting the beach adjacent to the south but has disturbed longshore transport, potentially leading to increased erosion to the north. The proposed CCMF provides real-time and post-performance monitoring of structure-influenced beaches, enabling timely decision-making at critical locations and appropriate remedial measures for efficient coastal management.

Immediate Implants, Immediate Loading, and Milled Double Bar Prosthesis (Titanium, Biohpp): A Case Report

Abstract To rehabilitate lower arch by placing immediate implants and immediate milled provisionals and provide double bar prosthesis for the long-term survival of implants. Full-mouth rehabilitation by integrating cone-beam computed tomography data three-dimensional printing technology helps in precise placement and predictable outcomes to the longevity of implants. Six immediate implants were placed in the lower arch using digitally guided surgery. Computer-aided design-computer-aided manufacture milled temporary prosthesis was also given within 24 h of the surgery. After allowing for osseointegration, the final prosthesis was made up of materials such as titanium (primary bar), PEEK (secondary bar), and high-impact polymer composite crowns. Splinting all the implants together with such framework designs reduces the loads on implants and addition of two bars produces a dampening effect and helps long-term survival of the same. Strategies used to preserve alveolar bone and soft tissue by immediate implant placement in fresh extraction sockets shorten the treatment span. Immediate loading of implants using temporary prosthesis can be done after attaining adequate primary stability. This case has a follow-up of 6 years. The milled double bars made out of titanium and BioHPP h provide dampening effect and thus long-term survival of the implant.

The role of impact parameter in typical close galaxy flybys

Abstract Close galaxy flybys, interactions during which two galaxies inter-penetrate, are frequent and can significantly affect the evolution of individual galaxies. Equal-mass flybys are extremely rare and almost exclusively distant, while frequent flybys have mass ratios $q=0.1$ or lower, with a secondary galaxy penetrating deep into the primary. This can result in comparable strengths of interaction between the two classes of flybys and lead to essentially the same effects. To demonstrate this, emphasise and explore the role of the impact parameter further, we performed a series of N-body simulations of typical flybys with varying relative impact parameters $b/R_{\mathrm{vir},1}$ ranging from $0.114$ to $0.272$ of the virial radius of the primary galaxy. Two-armed spirals form during flybys, with radii of origin correlated with the impact parameter and strengths well approximated with an inverted S-curve. The impact parameter does not affect the shape of induced spirals, and the lifetimes of a distinguished spiral structure appear to be constant, $T_\mathrm{LF} \sim 2$ Gyr. Bars, with strengths anti-correlated with the impact parameter, form after the encounter is over in simulations with $b/R_{\mathrm{vir},1} \leq 0.178$ and interaction strengths $S\geq0.076$ , but they are short-lived except for the stronger interactions with $S\geq0.129$ . We showcase an occurrence of multiple structures (ring-like, double bar) that survives for an exceptionally long time in one of the simulations. Effects on the pre-existing bar instability, that develops much later, are diverse: from an acceleration of bar formation, little to no effect, to even bar suppression. There is no uniform correlation between these effects and the impact parameter, as they are secondary effects, happening later in a post-flyby stage. Classical bulges are resilient to flyby interactions, while dark matter halos can significantly spin up in the amount anti-correlated with the impact parameter. There is an offset angle between the angular momentum vector of the dark matter halo and that of a disc, and it correlates linearly with the impact parameter. Thus, flybys remain an important pathway for structural evolution within galaxies in the local Universe.

Virtual Filter Membranes in a Microfluidic System for Sorting and Separating Size-Based Micro Polystyrene Beads by Illumination Intensity Design in Optically Induced Dielectrophoresis (ODEP)

In biomedical diagnosis, the efficient separation and purification of specific targets from clinical samples is the desired first step. Herein, the concept of virtual filter membranes based on optically-induced dielectrophoresis (ODEP) manipulation in a microfluidic channel is proposed as a light screening membrane for the separation of polystyrene (PS) microparticles with three different diameters of 15.8, 10.8 and 5.8 µm. The ODEP manipulation velocity of three types of PS microparticles reacted with the color brightness setting was investigated to determine the light intensity to induce an ODEP force higher than the drag force of fluid speed. The color brightness of the light bar in three areas of the light screening membrane was selected as 60%, 70% and 100% to isolate PS microparticles with diameters of 15.8, 10.8 and 5.8 µm, respectively. With a double light bar and a flow rate of 3 µL/min, the recovery rate and isolation purity was improved by 95.1~100% and 94.4~98.6% from the mixture of three types of PS microparticles within 2 min, respectively. This proposed light screening membrane could be a candidate for the separation of small-volume and rare biomedical samples, including circulating tumor cells (CTCs) and bacteria in the blood.

Associated risk factors for patients undergoing a unique or double Nuss bar placement for pectus excavatum.

Pectus excavatum is the most common chest wall deformity. Surgical correction via Nuss Procedure is a common approach. Patients with long-segment sternal depression require more than one Nuss bar to be inserted. Complications of Nuss procedure include surgical site infection and bar migration which may necessitate surgical re-intervention. There has been conflicting evidence regarding the safety profile of inserting two Nuss bars. We aim to specifically review the safety profile of two Nuss bar insertion and its complications. 179 consecutive patients who had undergone Nuss procedure between November 2013 and November 2021 were identified. Data analysis was performed on patient's age at time of operation, gender, height, weight, Haller index, pre-existing medical conditions, indication for surgery, duration of operation, numbers of bars placed, length of stay, post-operative pneumothorax, bar migration, superficial and deep infections, need for surgical intervention and mortality. Patients receiving two Nuss bars were at a significantly higher risk of developing infective complications. Lower weight and Haller index increase the risk of surgical site infection and infection requiring re-operation in this group of patients. A cut-off of 50 kg has a specificity of 92.1% with a sensitivity of 68.8% in regards to surgical site infection. Patients receiving two Nuss bars as a part of their Nuss procedure are at a significantly higher risk of developing infective complications. Selecting patients more than 50 kg to receive two Nuss bars appear to be a reasonable measure to reduce surgical site infection.

Calibrating a double aluminium bar with electrotensometric strain gauge attached

The transducers which are used for measuring force or weight are also called load cells. Most of those transducers use strain gauges to measure the applied force. In this paper, a calibration of a double aluminium bar with strain gauges attached is conducted in order to determine the major sources of error in the measurement process. The authors explain the entire process of calibration for a single load cell. The purpose is to determine the main measurement errors. The sensor was calibrated at maximum of 10 kg and loading were made by manual application of weights. The results of calibration reveal a very small hysteresis and linearity error which makes the sensor a reliable choice to measure force, weight, or load.

Modelling Studies of Retrofitted Anchorage System in Exterior Beam Column Joint by Supplementary Steel

A Nonlinear finite element based ABAQUS modeling studies were conducted to evaluate the performance of exterior Beam Column Joint (BCJ) under quasi-static test loads. Six integrated BCJ models representing different configurations of beam reinforcement anchored in joint are verified by using a novel retrofitting technique called "Post Installation of Supplementary Anchorage" (PISA) by using headed bar as supplementary steel. The configuration of beam reinforcement anchored in column are described by straight bar,90 degree bend ,180 degree hook (confirming to design code IS456:2000) and single head, double head bars (confirming to ACI 318-19, ACI 352R-02 ) and 90 degree long bend of ductile detailing (as per IS 13920-2016). Two series (A&B) of integrated joint specimens representing conventional (series-A) and retrofitted anchorage (series-B) systems are modeled and tested by using ABAQUS software. The test parameters considered are configuration of anchorage system and presence of supplementary anchorage. The test variables representing nonlinear performance of retrofitted joint system are Von Mises stress conditions, Principal tensile stress, Moment-Rotation, Degraded stiffness, Crack mechanics and Damage index. The results shows good improvement of post failure conditions of exterior beam-column joint such as relocation of plastic hinge mechanism and failure mechanics of retrofitted joint system. Also the results validated with experimental program on typical specimens casted and tested. This study imparts useful information on implicit retrofitting methods applied by external means in exterior beam-column joint. It also promotes performance based design principles with viable construction practice.

Librations in Double Bars of Galaxies

Librations in Double Bars of Galaxies

Cyclic Behaviour of Double Skin Composite Steel Plate Shear Wall Using Shape Memory Alloy with Various Aspect Ratios

Abstract: Shear wall is commonly used in high rise buildings to resist lateral forces. Reinforced concrete shear wall and steel shear wall are the commonly used. Now a days composite shear wall is most popular. Double skin composite shear wall consisting of two steel plates, concrete core, CFST column as boundary members, steel truss connectors, double wave form steel bars connected to steel truss. In this paper steel plate is replaced by shape memory alloy plate and determine the maximum load and total deformation. Cyclic behaviour of double skin composite steel plate shear wall using shape memory alloy with various aspect ratios can be studied using the software ANSYS 2021 R2. SMA plate shear wall provides better performance than in steel plate shear wall.

A Primary Support Design for Deep Shaft Construction Based on the Mechanism of Advanced Sequential Geopressure Release

The construction of 1500 m depth shaft in Xincheng Gold Mine, China, faces complex stress conditions such as high geostress (>50 MPa), high ground temperature (>50 °C), high water-pressure (>9 MPa), and highly corrosive. Traditional deep shafts excavated by the sinking and lining method cannot adapt to high geostress problems, such as rock bursts and large deformations, etc., in the deep shaft construction process. To avoid and adjust the high geostress induced the rockburst and large deformations, the mechanism of the advanced sequential geopressure release (ASGR) has been proposed for the ground control in deep shaft construction. In this paper, the safe distance between the concrete lining and the shaft excavation face is determined based on the ASGR mechanism, which can provide the space for geopressure release, and primary support based on rock mass quality and numerical simulation was employed to control the geopressure and deformation. A new support scheme for the deep shaft is proposed, using long bolts to restrain severe deformations, metal mesh, and a double reinforcement bar to improve the induced stress distribution. According to the results, the construction scheme of deep shaft has been improved, and the safe support distance of the proposed scheme is determined to be 12 m, with an interval of three excavation cycles. Compared to the original scheme of shaft lining after excavation, the proposed scheme based on the ASGR mechanism can effectively improve the geopressure release and benefit from controlling the rockburst and large deformation of deep shaft induced by high geostress conditions. The stress distribution in the lining is more uniform, and safety factor of the lining is increased to 2.0, which is benefit the long-term stability of deep shaft.

Evaluation and Classification of Double Bar Breakages Through Three-Axes Vibration Sensor in Induction Motors

The relative positions of broken bars can potentially change the current signature content, filter some of the components and hence lead to misleading in diagnostic process. Especially, if the positions of broken bars are in half pole pitch distance, the characteristic sidebands harmonics get lower which leads to decrease diagnostics ability of stator current based analysis. This paper proposes to analyze double bar breakages faults by monitoring the three-axes vibration ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-x</i> , <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-y</i> , <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">and -z</i> ) signals through an accelerometer in detail. The characteristics fault signatures are presented in axial <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-x</i> , radial <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-y</i> and gravity <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-z</i> axis vibrations and a neural network-based classifier (Multi-Layer Perceptron) is utilized to classify the type of double bar breakages. The findings are verified through the experiments. It is shown that some of characteristics fault signatures such as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2sf_{s}$ </tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3sf_{s}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2f_{r}$ </tex-math></inline-formula> ± <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2f_{s}$ </tex-math></inline-formula> at corresponding vibration spectra can provide more reliable result to detect and classify the broken bar fault in induction motors (IMs).

Analytical Studies on Retrofitted Anchorage System in Concrete using Strut and Tie Method

Analytical studies were conducted on force transfer mechanism of retrofitted anchorage system in structural concrete by Strut-and-Tie modeling (STM). Post Installation of Headed anchorage (PIHA) as supplementary system introduced for implicit strengthening of anchorage system. The boundaries of STM are considered under direct tension pull-out test. Five different configurations of conventional reinforcement anchorage in concrete with straight bar, 90-degree bend, 180-degree hook, single head and double head bars are retrofitted by using PIHA technique. The mechanics of force transfer in anchorage system was analyzed by STM and validated the results by experimental program. The study parameters considered are (i) location of nodal zone, (ii) strut angle, (iii) size of strut (concrete) contributed during failure. The study variables are (i) configuration of anchorage system (ii) characteristic node formation and (iii) presence of supplementary reinforcement. The result shows good agreement with experimental findings against failure mode, stress pattern, and location of critical zone in conventional and retrofitted anchorage system. Use of this study may further extended to assess theoretical evaluation of failure mode, formation of critical section and stressed regions of discrete RC elements such as corbel projection, bracket connections and beam-column joints.