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Influence line (IL) has emerged as very promising damage indices for bridge damage detection. This study proposed a method to localize and quantify damage in beam structures by estimating section flexibility change from deflection IL (DIL) change. To this end, the relationship between second derivative of DIL change and flexibility change was established. To remove noise interference in measurement, piecewise quadratic functions were used to fit and replace noisy DIL change curves, wherein the coefficients of quadratic function were determined via a sparse regularization method, considering the sparsity nature of damage that typically takes place in only a limited number of elements. The feasibility and accuracy of the proposed method are verified through numerical examples and laboratory experiments. Through four hypothetical damage scenarios of a simply supported beam with one or two damaged locations, its ability to quantify minor damage and its anti-noise robustness were well verified. Finally, a laboratory experiment on a simply supported aluminum beam illustrated that the location and extent of damage could be successfully identified in the single-damage and double-damage cases. The numerical and experimental results indicate that the proposed method is promising for future damage localization and quantification of bridge structures. [ABSTRACT FROM AUTHOR]

This study synthesized the water-permeable and hydrophobic property of water-based polyurethane (WPU) and applied it to nylon fiber-based functional textiles. Specifically, poly-stearyl acrylate (PSA) homopolymers with different molecular weights were used as end-capping agents in the WPU to form water-based polyurethane with acrylate terminal (WPUA). In the WPUA process, dimethylacetamide was adopted as a neutralizing agent to form a stable WPUA emulsion. The effects of the design parameters, such as the hydrophilic ionic group dimethylol propionic acid (DMPA), the PSA molecular weight and content, were set as the control factors and are analyzed by the Taguchi method and gray relational analysis (GRA). The water-repellent characteristic, water vapor permeability (WVP) and fabric flexural rigidity were considered as performance parameters as multi-qualities. The Taguchi method was based on the analysis of variance and implemented orthogonal arrays for experimental design. Each performance parameter was optimized independently. Then, the performance parameters were optimized together with GRA. According to the experimental results, the most important factor for the water-repellent characteristic, WVP and fabric flexural rigidity is the DMPA content, followed by the PSA molecular weight and content. The corresponding results showed that in the optimal parameter combination, the content of DMPA was 30.8 phm (parts per hundred monomer by weight), the PSA molecular weight was 3000 g/mol and the PSA content was 4 phm. After WPUA padding, the water contact angle of the water-repellent nylon was 135.3°, the WVP was 2271.7 g/m2/day and the flexural rigidity was 2.7 cm. [ABSTRACT FROM AUTHOR]

Background: Modular connections in total hip arthroplasty (THA) offer surgical advantages, but can contribute to implant fretting and corrosion due to micromotion at the head-stem interface. Previous studies implicated lower flexural rigidity as a key contributing factor to THA corrosion and fretting, but none associated flexural rigidity with direct histological evaluation or magnetic resonance imaging (MRI) outcomes. The purpose of this study was to determine how implant flexural rigidity is associated with MRI imaging metrics and histopathological outcomes in patients who have a failed THA., Methods: Patients requiring revision THA surgery underwent preoperative MRIs with 3-dimensional multispectral imaging techniques to suppress metal artifacts. The MRI images were graded for adverse local tissue reactions. For each hip, trunnion flexural rigidity was measured from the retrieved femoral stem, and a periprosthetic tissue sample was retrieved and evaluated using semiquantitative histology. Generalized linear models and analyses of variance were used to assess associations between flexural rigidity and MRI and histology outcomes., Results: A total of 106 THA stems were retrieved (46 women and 60 men, age: 68 years (range, 60 to 73 years). After adjustment for length of implantation, flexural rigidity was negatively correlated with histologic aseptic lymphocyte-dominant vasculitis-associated lesion severity (β = -26.27, P = .018), Fujishiro lymphocyte grading (β = -13.4, P = .039), perivascular lymphocyte layers (β = -17.8, P = .022), the grade of tissue organization (β = -22.5, P = .009), the presence of diffuse synovitis (β = -66.5, P = .003), and the presence of lymphoid aggregates (β = -75.9, P = .022). No association was found between MRI metrics and flexural rigidity., Conclusions: Among these implants, decreased trunnion stiffness was associated with increased histologic features of adverse host-mediated soft tissue reactions., (Copyright © 2024 Elsevier Inc. All rights reserved.)

In Egypt, large quantities of coarse granite wastes are produced annually during the quarrying operations of granite rocks. This waste represents a potentially useful source of material for a variety of applications such as a filler material in epoxy granite composite material. In this work a new eco-friendly composite material studied as a substitute for machine tools traditional materials, like cast iron, to produce better efficiency with lower cost. This study aims to investigate the mechanical properties of granite epoxy composite by using the local epoxy (kemapoxy 150) and the granite residues in the Egyptian quarries. The investigated processing variable was epoxy content, and the mechanical characterization ware carried out by compressive and flexural tests according to the ASTM standard method B. Commercially available, Aswan red granite was procured, crushed, and sieved to three size ranges from 0.150 to 8 mm, respectively. Epoxy ratios of 80:20, 85:15 have been used with granite aggregate size mix with small, medium, and coarse size proportions of 50:25:25 respectively for preparing the specimens with granite granular size range (0.150-8) mm. The results show that Epoxy granite composite with granite to epoxy ratio of 80:20% wt. induced the highest compressive strength (72.15 MPa) while the composite with the ratio of 85:15% wt. induced the highest flexural strength (20.1 MPa). Epoxy granite composite show superior results with respect to cement concrete, polyester concrete, and natural granite. [ABSTRACT FROM AUTHOR]

When an elevator rope for a high-rise building is forcibly excited by the displacement of the building induced by wind force and/or by long-period ground motion, rope displacement becomes large even if the ground acceleration and the building acceleration is small. Vibration suppressor is used to reduce the rope vibration. The elevator rope is generally modeled using a string with viscous damping. However, the flexural rigidity and the damping property of the rope are not clear yet. In this paper, we proposed a beam model with viscous damping and structural damping. And we also proposed an estimation method of 3 parameters (equivalent flexural rigidity, viscous damping ratio, structural damping ratio). Experiments of forced vibration with/without vibration suppressor and finite difference analyses of rope vibration were performed. It is clear that the identified parameters obtained by the limited conditions of vibration suppressor are applicable to other conditions.

The study aims to fully explicate the bending behavior of tea stalks under the condition of large deflection, which is crucial to improve the working performance of mechanized harvesting equipment. The mechanical model of the stalk was assumed to be a non-prismatic beam with virtual internodes that could differ from actual internodes. With the model, the stalk can be freely divided into multiple virtual internodes, whose flexural rigidities can be determined by solving an optimization problem, and deflection curves can be predicted after determining the positions of virtual nodes under given loads. Moreover, a novel method was proposed to obtain the deflection curve of the stalk based on the techniques of binocular vision and non-uniform rational B-spline (NURBS) curve fitting. The results show that R-squared values of fitted 2nd-degree NURBS curves of bending shape of tea stalks range from 0.9576 to 0.9964, with an average of 0.9797. The results indicate that flexural rigidity decreases from the bottom to the top of the tea stalk, and the deflection curve could be predicted more precisely with the model of piecewise flexural rigidities than that of average flexural rigidity. The study could be applied to the optimization design of the cutter and adaptive adjustment techniques of operational parameters for tea picking machines.

Embroidery through computer aided semi-automatic machines is one of the most widely used option for the surface ornamentation of apparel fabrics at present. Since the embroidery process includes addition of certain amount of embroidery-threads depending upon the design motif, it is quite obvious that basic physical and functional properties of fabric are subject to change. It is therefore important to develop an algorithm or empirical equation for proper prediction of the properties of the embroidered fabric, relevant to its required end-use in apparel industry. In this context, an effort has been made to determine a prediction equation through linear multiple regressions for the prediction of longitudinal stiffness of embroidered fabric in terms of flexural rigidity in warp direction of the base fabric, considering the input parameters as warp-way flexural rigidity of the base fabric, breaking load and linear density of the embroidery thread, stitch density, average stitch length and average stitch angle of the embroidery design. The final Prediction model is statistically verified taking new embroidery samples of different varieties. It is found that the model can predict with a very satisfactory level of accuracy. Also, the influences of the embroidery parameters in this context have been analyzed through the corresponding regression coefficients and the three dimensional (3D) surface curves. Stitch density has been emerged as the most influential parameter, followed by the stitch length and the stitch angle. [ABSTRACT FROM AUTHOR]

This paper characterises the flexural properties of relatively slender structural members (beams) manufactured using a FDM-based 3D printer. The primary goal is to assess the influence of infill properties on flexural rigidity through a parametric investigation. Infill percentage, infill orientation, and member thickness provided the parametric variation. The beams were tested by three-point bending, free vibration, and buckling. The tests showed that flexural rigidity varied linearly with infill percentage over most of the range considered, but fell off quickly below 10% infill. The optimal infill percentage that maximised specific flexural rigidity (flexural rigidity to length density) of the beams was determined to be between 10% and 20%.

A three-dimensional finite element technique was used to analyse single pile lateral response subjected to pure lateral load. The main objective of this study is to assess the influence of the pile slenderness ratio on the lateral behaviour of single pile. The lateral single pile response in this assessment considered both lateral pile displacement and lateral soil resistance. As a result, modified p-y curves for lateral single pile response were improved when taking into account the influence lateral load magnitudes, pile cross sectional shape and flexural rigidity of the pile. The finite element method includes linear elastic, Mohr-Coulomb and 16-nodes interface models to represent the pile behaviour, soil performance and interface element, respectively. It can be concluded that the lateral pile deformation and lateral soil resistance because of the lateral load are always influenced by lateral load intensity and soil type as well as a pile slenderness ratio (L/D). The pile under an intermediate and large amount of loading (in case of cohesionless soil) has more resistance (low lateral displacement) than the pile embedded on the cohesion soil. In addition, it can be observed that the square-shaped pile is able to resist the load by about 30% more than the circular pile. On the other hand, pile in cohesionless soil was less affected by the change in EI compared with that in cohesive soil.

Premise: Because of their own weight and additional wind forces, plants are exposed to various bending and torsional loads that sometimes require contradictory structural characteristics and mechanical properties. The resulting trade‐off between flexural and torsional rigidity can be quantified and compared using the dimensionless twist‐to‐bend ratio. Methods: The flexural rigidity of the stems of Carex pendula was determined by 2‐point bending tests. Additionally, 4‐point bending tests and torsional tests were carried out on segments of two internodes directly below the inflorescences to measure flexural and torsional rigidity. Anatomical investigations were performed to quantify the cross‐sectional distribution of their tissues. Results: The flexural rigidity of the stems, segments of the apical internode 1, and the more basal internode 2 differed significantly from each other, whereas the bending elastic moduli were not significantly different. The torsional rigidity of segments of internode 2 was a factor of 3.3 higher than that of internode 1, whereas the torsional moduli did not differ significantly. The twist‐to‐bend ratios of segments of internode 1 and 2 reached values between 85 and 403. Light microscopic investigations revealed a triangular stem possessing individual sclerenchyma strands, with internode 2 having significantly more strands than internode 1. Conclusions: In the case of Carex pendula, flexural and torsional rigidity are adapted to the given mechanical constraints by significant changes in morphometric variables (axial and polar second moment of area, number of sclerenchyma strands), whereas the material properties (bending and torsional modulus) do not change markedly along the stem. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A proteolytic enzyme, papain, has been used for bio-polishing of mulberry silk. Improvement in lustre, with no significant change in absorbency, flexural rigidity and crease recovery, due to the cleaning of the fibre surface by the enzyme is reported. A chemometric experimental design is used with two variables and five levels. [ABSTRACT FROM AUTHOR]

Cross-laminated timber (CLT) plates are new components in modern wooden building structures and have good integrity, stability, and high strength. However, the bending performance of CLT plate is affected by the stacking method of laminates. This study adopted two different stacking methods (three-layer cross and four-layer cross) to make four CLT two-way slabs by using Larix gmelinii slab and polyurethane structural adhesive as raw materials. The slabs were divided into two groups to reveal the effects of stacking method on the bending performance of CLT two-way plates. A jack was used to apply concentrated load on a single point of the middle span of slabs, and the strain, deflection, and ultimate load data were measured. The crack development and failure mode were observed. The ultimate failure characteristics and failure mechanism were discussed, and the finite element model of CLT two-way slab was established using structural analysis software. The influence of elastic-plastic and plywood layers on the bending properties of CLT two-way slab was analyzed, and the results were compared with the experimental results. Results show that the failure modes of CLT two-way slabs are mainly from the transverse grain tensile failure of the slab bottom, and the bearing capacity decreases rapidly when the load reaches to approximately 80% of the ultimate load. For the same thickness of CLT plate, the flexural capacity of four-layer plate is increased by 14.08%, and the elastic bending stiffness is increased by 13.63% compared with three-layer plate. The overall bearing capacity and flexural stiffness of a two-way CLT slab with the same thickness can be improved by increasing the number of laminates when four sides are simply supported. The optimal number of laminates is five. The result of finite element simulation aligns with the test, showing that the test results and analysis are reliable. This study can provide references for future engineering design. [ABSTRACT FROM AUTHOR]

In this study the effects of fabric parameters such as fabric weight (GSM), lycra content and weave on characteristics of stretchable denim fabric was studied. The physical and stretch properties such as thickness, tensile strength, flexural rigidity, stretch properties (stretch, growth and elastic recovery) and air permeability of the fabrics were tested. The test result revealed that increasing the fabric weight enhances the comfort and performances of the fabric except the fabric flexural rigidity and air permeability. As Lycra contents in fabric increases flexural rigidity of fabric increased but breaking strength in weft and air permeability get reduced. The different fabric constructional weave has also diverse effect on fabric flexural rigidity and air permeability related to comfort and performance of stretchable denim fabric. Furthermore, increasing in crimp in fabric structure increase the flexural rigidity and decrease in air permeability. [ABSTRACT FROM AUTHOR]

Submerged freshwater macrophytes are frequently used in hydraulic laboratories to study flow–plant interactions and the role of plants in aquatic ecosystems, but environmental conditions in flume facilities are often suboptimal for plants and can cause plant stress. Physiological responses of plants under stress can trigger modifications in plant biomechanics, which may affect plant–flow interactions and compromise experimental results. In the extreme, dead plants cannot be expected to reveal how live plants interact with flowing water, but stressed plants that are not visibly unhealthy may also affect experimental results. The present work aims to assess if and how environmental conditions typical of flume facilities can impact plant health status and induce variations in plant biomechanics. Using chlorophyll fluorescence analysis, a standard method for assessing plant health, we found that freshwater macrophytes can be significantly stressed under conditions typically found in hydraulic laboratories. Even though the abiotic factors investigated affected different species in different ways, exposure to tap water and low irradiance were the most stressful conditions for freshwater macrophytes. Biomechanical properties with a primary role in flow–plant physical interactions (e.g. flexural rigidity) changed significantly as a result of exposure to stressful conditions. In general, plant stress was associated with a reduction in flexural rigidity at the top of plant stems, suggesting a potential effect on plant hydrodynamics when leaves and petioles are considered. The maximum quantum yield of photosystem II, used as proxy of plant health status, was positively correlated with flexural rigidity of plant stems. [ABSTRACT FROM AUTHOR]

The presence of intermediate supports usually imposes difficulties in identifying the tension force of stayed cables in cable-stayed bridges or hanger cables in arch bridges. This paper establishes the partial differential equations of motion of the cable and derives two numerical models with (Model 1) and without (Model 2) considering the flexural rigidity. The effects of two intermediate supports on the identification accuracy of the cable tension force are further studied analytically and experimentally. The effects of several non-dimensional parameters (e.g. damper location, support stiffness, flexural rigidity, and mode order of the cable) on the identification accuracy of the models are also investigated. It is theoretically concluded that the simplified Model 2 provides acceptable accuracy on tension force identification when the non-dimensional parameter ξ is greater than 90 (slender cables), whereas the accurate Model 1 can be applied for tension force identification at any scenarios. The feasibility of two models is further verified by three numerical examples and field tests on two real-world arch bridges. [ABSTRACT FROM AUTHOR]

This article investigates how the bending stiffness of the core thread and the effect threads affect the average values and the variability of the structural properties of resultant fancy yarns. The Design of Experiment technique was used to study the effects of individual factors and the interactions of factors. The analysis indicated that that the bending stiffness of the effect thread was a main factor. Increases in the effect thread bending stiffness led to significant increases of the size of fancy profile and reductions of the number of fancy profiles. Additionally, there was a strong interaction effect between the bending stiffness of the core thread and the bending stiffness of the effect thread which influenced the structures of the resultant fancy yarns. It was also found that variations in the bending stiffness of the input threads were reflected in similar variations in the size and number of fancy profiles. The study is important for engineering the structure and the variation in structural properties of fancy yarns by selecting appropriate input threads. [ABSTRACT FROM AUTHOR]

The yarn structure and fabric interlacing pattern are determining parameters for fabric properties. The current study focusses on the multi-response optimization of certain fabric properties like shrinkage, areal density, thickness, flexural rigidity, and bending modulus using principal component analysis for optimum properties. Yarn twist (four different levels), fabric weave design (plain and twill), and yarn type (carded and combed) were the variables of the study. The Taguchi approach of the orthogonal array was sued for designing the experiments, and eight different samples were produced. The yarn twist and fabric weave design were found to have significant effect on these properties of the fabric. Furthermore, using analysis of the variance method, contribution% of parameters to these properties was determined.

A theoretical model is presented in the analysis and prediction of the complete load-deflection behavior of fixed-horizontally restrained reinforced concrete polygonal slabs under uniform loading. The limiting cases of fixed reinforced concrete square and circular slabs are also deduced. The proposed model considers three stages, elastic, elasto-plastic and plastic. In the elastic and -elasto-plastic stages, the results of classical plate theory are used. The cracking of concrete and yielding of steel reinforcement are accounted for by suitably modifying flexural rigidity. Changes that occur in support conditions due to possible yielding are also considered. In the plastic stage a rigid plastic membrane analysis is presented. A method is proposed to predict the real ultimate load (including membrane action) and the deflection at the ultimate load.

The use of shear connectors in a composite system tends to impart heterogeneity and needs an expert workmanship as well as special equipment for fabrication. In order to avoid such necessities, the present study is focused on developing steel concrete composite sandwich panels without use of any shear connectors by embedding flanges of the profile sheet in the concrete. Two configurations, (i) P1, where both the skins are a composite with flanges of profile sheet embedded in self-compacting concrete and (ii) P2, where the top skin alone is a composite with flanges of profile sheet embedded in self-compacting concrete, are studied experimentally under four-point bending and are compared with an Reinforced cement concrete (RCC) slab of same dimension. In both the configurations, the webs of the profile sheet act as core in providing shear stability to the panel. The configurations P1 and P2 have 38% and 22% weight of an RCC slab and exhibited 77% and 60% strength of the RCC slab respectively. Apart from good strength-to-weight ratio, the configurations P1 and P2 exhibited better ductility, stiffness and flexural rigidity posing to be a better alternative. [ABSTRACT FROM AUTHOR]

Vegetation patches play an important role in controlling sediment deposition in shallow aquatic environments such as coastal saltmarshes and fluvial systems. However, predicting deposition around vegetation patches is difficult due to the complexity of patch morphology and their dynamic interaction with the flow. Here we incorporate a biomechanical model, parameterized using field data, within a 3‐D computational fluid dynamics model which allows prediction of individual shoot reconfiguration within patches due to flow forcing. The model predicts velocity attenuation and bed shear stresses within the wake of the patch which agree spatially with accretion patterns measured in the field using terrestrial lidar. The model is applied to sparse patches of Suaeda maritima, located in saltmarshes of coastal habitats, to explore the role of (I) shoot distribution, (II) patch geometry, (III) shoot flexural rigidity, and (IV) bulk flow velocity in determining the length of the predicted wake region. We demonstrate that for Suaeda maritima, with intermediate rigidity, the vertical shear layer over the vegetation controls the length of the predicted wake region. Consequently, reconfiguration due to flexural rigidity strongly impacts on wake length, confounding the relationship between patch height and wake length. A simplified model for predicting wake length based on shoot reconfiguration is applied to the simulation data and shows good agreement. The results demonstrate that the observed wake characteristics can be well explained by intraspecific variability in flexural rigidity, thus demonstrating the importance of biomechanical traits in determining flow‐vegetation‐sediment interactions. Key Points: We develop a new field‐parameterized model for simulating shoot reconfiguration within vegetation patchesWake length is controlled by a vertical shear layer, which in turn depends on shoot flexural rigidity and flow velocityA simplified beam equation model allows prediction of wake length from velocity and flexural rigidity [ABSTRACT FROM AUTHOR]

This paper deals with the numerical calculation method of deflection deformation of rice stalks. Due to large deflection of rice stalks caused by reel operation, it is improper to adopt the conventional formula that is usually used in small deflection calculation to fit rice stalk deformation curves. Therefore, a large deflection calculation formula in combination with Simpson's formula was utilized to compute flexural rigidity (EI) and to fit curves. The experiments were conducted under different loads (0.03, 0.04, 0.05, 0.06, and 0.07 N) on a self-established deflection testing rig to verify this method. As a result, the measured results corresponded considerably to ones predicted by this method; furthermore, the flexural rigidity was maintained at a stable level under different loads. This study can provide the basis for establishing a complete deformation model of rice plant and can also be applied in deflection calculation of other stalk crops. [ABSTRACT FROM AUTHOR]

Cold-formed steel (CFS) built-up members are formed by connecting several single members by fasteners. This paper presents experimental, numerical and analytical studies on the effect of fastener configurations on the flexural rigidity of built-up sections. In this research, two zinc-coated steel C-sections are connected back-to-back to form a double-web built-up I-section, which is subject to weak-axis bending. A closed-formed expression for the flexural rigidity of built-up sections as a function of fastener stiffness, number and position of fasteners, and section geometry is then derived. This is validated against the tests and finite element modelling, and can be adapted more generally to determine the stiffness and global strength of CFS built-up members in bending. • The study is about how fastener configurations affect the effective flexural rigidity of cold-formed steel built-up sections. • Tested fasteners are screws, bolts and welds. • The effective flexural rigidity is a function of fastener stiffness, number and position of fasteners, and section geometry. • Effective flexural rigidity affects stiffness and strength of built-up members in bending and members subject to buckling. [ABSTRACT FROM AUTHOR]

• Reduction of taper size and stiffness is a trade-off; micromotion is significantly increased. • Materials with lower elastic modulus can lead to higher micromotion. • High activity levels increase micromotion between prosthesis head and stem. • V40 taper design showed 300% higher micromotion compared to 12/14 tapers. • Instead of smaller tapers a rounded square neck region should be used to increase the range of motion. Fretting corrosion as one reason for failure of modular hip prostheses has been associated with micromotion at the head taper junction. Historically the taper diameter was reduced to improve the range of motion of the hip joint. In combination with other developments, this was accompanied by increased observations of taper fretting, possibly due to the reduced flexural rigidity of smaller tapers. The aim of the study was to investigate how the flexural rigidity of tapers influences the amount of micromotion at the head taper junction. Three different stem and two different taper designs were manufactured. Experimental testing was performed using three different activity levels with peak loads representing walking, stair climbing and stumbling. The relative motion at the head-stem taper was measured in six degrees of freedom. Micromotion was obtained by subtraction of the elastic deformation derived from monoblock and finite element analysis. Less rigid tapers lead to increased micromotion between the head and stem, enlarging the risk of fretting corrosion. The influence of the stem design on micromotion is secondary to taper design. Manufacturers should consider stiffer taper designs to reduce micromotion within the head taper junction. [ABSTRACT FROM AUTHOR]

This paper characterises the flexural properties of relatively slender structural members (beams) manufactured using a FDM-based 3D printer. The primary goal is to assess the influence of infill properties on flexural rigidity through a parametric investigation. Infill percentage, infill orientation, and member thickness provided the parametric variation. The beams were tested by three-point bending, free vibration, and buckling. The tests showed that flexural rigidity varied linearly with infill percentage over most of the range considered, but fell off quickly below 10% infill. The optimal infill percentage that maximised specific flexural rigidity (flexural rigidity to length density) of the beams was determined to be between 10% and 20%. [ABSTRACT FROM AUTHOR]

Tef (Eragrostistef (Zucc.) Trotter) is a typical crop growing in most areas of Ethiopia, with the first area coverage. In this study mechanical properties of Tef stem the major four varieties, viz; Local, Dz-Cr-438- (Kora), Dz-Cr-387/RIL-355 (Quncho) and Dz-01-1880 (Guduru) was determined. The factors considered were moisture content, diameter and thickness of the Tef stem and analyze their mechanical properties using Texture Analyzer and Universal Testing Machine. The result indicated that the minimum and maximum value of modulus of elasticity was 0.13 and 2.6 Gpa at moisture level 8.82% and 16.6%; 1.03 and 3.6 Gpa at moisture level 10.32% and 13.79%; 0.85 and 3.22Gpa at moisture level 7.65% and 12.72%; 1.27 and 3.88 Gpa at moisture level 5.5% and 19.70% at upper and bottom position for Local, Kora, Quncho and Guduru varieties respectively. The shear stress at different moisture content was 8.58 and 32.12 MPa; 6.30 and 28.40 MPa; 10 and 26.30 MPa; 2 and 29.60 MPa at upper and bottom position for Local, Kora, Quncho and Guduru varieties respectively. The ability to track significant differences between the varieties and their individual mechanical and physical properties provides a path forward for tailoring harvesting, threshing and separation operations. To tackle the problem of lodging it is better to look on the morphological structure of each variety of Tef stem that has better modulus of elasticity, flexural rigidity and diameter of the stem. Since, the Tef stem has better mechanical properties than some cereals it is recommended to identify the fiber properties and use as material for composite. [ABSTRACT FROM AUTHOR]

To accurately predict the optimum supplemental modal damping ratio of the cable and the corresponding size of the inertial mass damper (IMD), combined effects of the cable sag, the cable flexural rigidity, and the boundary conditions on the control performance of the cable with the IMD are well investigated in this refined study. An analytical model of the cable-IMD system considering these effects is developed. The equation of motion of the cable-IMD system is transformed into a complex eigenvalue problem through the finite difference method. Experimental results from a scaled cable model with an IMD are then used to verify theoretical solutions. Three typical cables in actual cable-stayed bridges are selected for case studies. The results show that the theoretically predicted modal damping ratios of the cable with an IMD, taking into account the sag and the flexural rigidity, agree well with those identified from experimental results, while would be often overestimated with a taut-cable model. Moreover, experimental damping ratios of the cable always fall between those theoretically calculated with fixed ends or pinned ends for each case. Finally, to be conservative in actual design, it is recommended to use the cable-IMD system model with fixed ends to calculate the required damper size and predict the resulting modal damping ratio of the cable, since the corresponding theoretical solution often gives the lower bound of supplemental damping ratio of the cable. [ABSTRACT FROM AUTHOR]

There is considerable controversy regarding the long-term strength of continents (T e). While some authors obtain both low and high T eestimates from the Bouguer coherence and suggest that both crust and mantle contribute to lithospheric strength, others obtain estimates of only

Abstract Arc-shaped forceps are important in pharyngeal cancer surgery, endoscopic sinus surgery, and single port surgery. Rotating the gripper of an arc-shaped forceps with respect to its shaft axis can improve the manipulability of the forceps. Concentric pipe structures consisting of inner and outer pipes are often used for this purpose. The inner pipe transmits rotations from its proximal end to distal end. However, the shape of the bent inner pipe is generally different from that of the outer pipe, and this causes large friction between the outer and inner pipes. To reduce friction, a plastic tube is often used for the inner pipe. However, since its torsional rigidity is low, this results in a large twist angle. This paper proposes a procedure to fit a metal bent inner pipe to an outer pipe by adjusting the flexural rigidity of the inner pipe with slits to reduce the friction. The procedure minimizes the twist angle between the proximal and distal end of the arc-shaped forceps by reducing the torque required to rotate its metal inner pipe. We develop a 5 mm forceps with a 3.5 mm inner pipe. The twist angle is 2.8° when a load torque of 20 Nmm is applied, which is a typical load torque for suturing, whereas the twist angle of a PEEK (polyetheretherketone) inner pipe is 24.3° in simulation. Ex vivo experiments show that the required forceps torque is small in simulated clinical scenarios.

The article discusses flexural rigidity of footwear as the key factor of its quality. The analysis of methods and devices for determining flexural rigidity is done. These methods and devices enable to simulate the actual flexing mechanism of footwear under walking. In order to improve methodology and instruments for determining flexural rigidity the formula is developed which allows for comparative assessment of flexural rigidity index measured under testing with various instruments. Applying developed recommendations allows for adequate precise assessment of flexural rigidity index of footwear of various design.

In-service dimensional stability of the VVER-1000 reactor fuel assemblies (FA) depends to a great extent on their flexural rigidity. A decrease in the flexural rigidity in the process of the FA operation in the reactor may lead to such FA bowing as will make it difficult for the absorber rods of the reactor control and protection system to move in the FA guide channels. This is not admissible from the point of view of the reactor operation safety. This paper describes a method and a facility for the hot cell testing of the irradiated VVER-1000 FA flexural rigidity. The method is based on measurements of the FA bowing induced by cross-sectional loading. The load applied to the spacer grids is perpendicular to the grid face, and the FA bowing is measured optically using a TV camera. The facility can also be used to test the flexural rigidity of the FA skeleton after all of the fuel rods are removed. Several tens of VVER-1000 FAs with a burnup of ∼4 to ∼65МWday/kgU were tested by Dimitrovgrad Research Institute of Atomic Reactors. The generalization and an analysis of the test results have made it possible to identify the major factors that contribute to the in-service change in the flexural rigidity of the VVER-1000 FAs and to determine the experimental dependence of its change on burnup. It has been shown that an increase in the burnup causes the flexural rigidity of TVSA and TVS-2 FAs with a rigid skeleton to decrease to the minimum value of ∼5kgf/mm, the burnup being 45–50МWday/kgU, and then to start growing again. It has been found out that it is the fuel bundle, specifically the change in the force of the fuel rod compression in the spacer grid, which is responsible for the change in the FA flexural rigidity. The maximum TVSA and TVS-2 FA bowing is in the range of 8–11mm whereas the burnup is 48–63МWday/kgU. The newly adopted TVSA and TVS-2 FA designs have contributed to the safe operation of the VVER-1000 control and protection system's absorber rods.