Tangential Variation Research Articles

Compressive loading of structural insulated panels and conventional stud walls: a study

Structural insulated panels (SIPs) are structural elements comprising a core of expanded polystyrene insulation sandwiched between two oriented strand boards. They can replace conventional joist floors and stud walls in low-rise residential construction. Three identical samples of full-scale SIP walls and stud walls were tested according to ASTM standards and experimental results for the specimens were obtained in terms of their ultimate load capacity and failure mechanism. Comparison of the load–deformation diagrams of the SIPs and stud walls showed that tangential stiffness variation of the former occurred in the hardening mode, whereas the variation for the latter was in two stages, hardening and softening. Regarding compressive loading, the results showed that SIPs are as good as conventional wood framing of the same size. Therefore, SIP walls are very efficient in the case of axial compressive loading.

Stretchable and conformable variable stiffness device through an electrorheological fluid.

Stiffness variations extend creatures' functions and capabilities to deal with complex environments. In this study, we proposed an electrorheological fluid-based variable stiffness device, named VSERF, made up of soft materials. Our device is soft, thin, and stretchable so that it can conform to surfaces with complex morphologies. The stiffness of the VSERF device can be continuously, independently, and reversibly adjusted by applying an electric field. It achieves 14.8-times compressive stiffness variation and 3.5-times tangential stiffness variation when the electric field intensity increases from 0 V mm-1 to 750 V mm-1. The VSERF device is able to return to its initial shape after removing the external force and electric field, allowing it to be reused. The effects of stretching and bending on the device's capability of stiffness variations are investigated experimentally and the results show that the stiffness variation is unaffected by a stretching strain of up to 20% and a bending curvature of up to 50 m-1. Finally, we show that the VSERF device is capable of conforming to complex surfaces (coral stones, pencils, and 3D printed cubes) in its inactive state, hanging on them with a weight of up to 80 g (19 times of its own weight) in its active state, and detaching when the electric field is removed. The device's short-term and long-term stabilities are experimentally investigated as well. The demonstration of the VSERF's attaching and detaching ability shows that the stiffness-variation device's adaptability to complex environments can be improved.

The Influence of Headform/Helmet Friction on Head Impact Biomechanics in Oblique Impacts at Different Tangential Velocities

Oblique impacts of the helmet against the ground are the most frequent scenarios in real-world motorcycle crashes. The combination of two factors that largely affect the results of oblique impact tests are discussed in this work. This study aims to quantify the effect of the friction at the interface between the headform and the interior of a motorcycle helmet at different magnitudes of tangential velocity. The helmeted headform, with low friction and high friction surface of the headform, was dropped against three oblique anvils at different impact velocities resulting in three different magnitudes of the tangential velocity (3.27 m/s, 5.66 m/s, 8.08 m/s) with the same normal component of the impact velocity (5.66 m/s). Three impact directions (front, left-side and right-side) and three repetitions per impact condition were tested resulting in 54 impacts. Tangential velocity variation showed little effect on the linear acceleration results. On the contrary, the rotational results showed that the effect of the headform’s surface depends on the magnitude of the tangential velocity and on the impact direction. These results indicate that a combination of low friction with low tangential velocities may result into underprediction of the rotational headform variables that would not be representative of real-world conditions.

Codimension one minimizers of highly amphiphilic mixtures

We present a modified form of the Functionalized Cahn–Hilliard (FCH) functional which models highly amphiphilic systems in solvent. A molecule is highly amphiphilic if the energy of a molecule isolated within the bulk solvent molecule is prohibitively high. For such systems once the amphiphilic molecules assemble into a structure it is very rare for a molecule to exchange back into the bulk. The highly amphiphilic FCH functional has a well with limited smoothness and admits compactly supported critical points. In the limit of molecular length ε→0 we consider sequences with bounded energy whose support resides within an ε-neighborhood of a fixed codimension one interface. We show that the FCH energy is uniformly bounded from below, independent of ε>0, and identify assumptions on tangential variation of sequences that guarantee the existence of subsequences that converge to a weak solution of a rescaled bilayer profile equation, and show that sequences with limited tangential variation enjoy a lim inf inequality. For fixed codimension one interfaces we construct bounded energy sequences which converge to the bilayer profile and others with larger tangential variation which do not converge to the bilayer profile but whose limiting energy can violate the lim inf inequality, depending upon the energy parameters.

Prediction of the Variation on Steering Wheel Shimmy due to Tangential and Radial Force Variation of the Tyres

<div class="section abstract"><div class="htmlview paragraph">The objective of this work is to develop a process that predicts the amount of steering wheel shimmy in a vehicle due to the tangential and radial force variation in the Tyre/Wheel assembly and also other components affecting shimmy. Steering wheel shimmy is defined as the torsional oscillation of the steering wheel due to excitation at the wheels. The tangential and radial force variation was modelled based on test data and applied on the wheels as excitation. Variation of these forces with the vehicle velocity was considered. The various factors that affect shimmy were then established. These factors were then divided into two categories - Geometric and Non-Geometric. A DOE was done, while considering the manufacturing variations, to study the sensitivity of those factors on shimmy. The DOE results were used to fit a regression model that predicts the shimmy velocity while considering the factors as inputs. The regression model was then considered for a Montecarlo simulation to estimate the distribution of shimmy velocity. A Normal or Weibull distribution was considered for the MonteCarlo Simulation for each of the factors in the DOE study. This distribution was then compared against a target. The target was used to design the suspension such that it is robust enough to withstand the manufacturing variations of the factors effecting shimmy.</div></div>

Dynamic response of functionally graded plates resting on two-parameter-based elastic foundation model using a quasi-3D theory

In this article, an improved quasi 3-D theory, which considers transverse normal strain effect along with inverse tangential variation of in-plane displacements across plate thickness, is employed to encapsulate the response of thick functionally graded plates. The present model satisfies both non-linear variation and zero transverse shear stresses across plate thickness. The governing equations of plate are obtained using Lagrange equation and solved by applying finite element procedure. The adaptability of the proposed theory is handled by considering the impact of various parameters on dynamic response of plate through several illustrations. The present model gives incredible concurrence with accessible literature.

Effects of Prolonged and Acute Muscle Pain on the Force Control Strategy During Isometric Contractions.

Musculoskeletal pain is associated with multiple adaptions in movement control. This study aimed to determine whether changes in movement control acquired during acute pain are maintained over days of pain exposure. On day 0, the extensor carpi radialis brevis muscle of healthy participants was injected with nerve growth factor (NGF) to induce persistent movement-evoked pain (n=13) or isotonic saline as a control (n=13). On day 2, short-lasting pain was induced by injection of hypertonic saline into extensor carpi radialis brevis muscles of all participants. Three-dimensional force components were recorded during submaximal isometric wrist extensions on day 0, day 4, and before, during, and after saline-induced pain on day 2. Standard deviation (variation of task-related force) and total excursion of center of pressure (variation of force direction) were assessed. Maximal movement-evoked pain was 3.3±.4 (0-10 numeric scale) in the NGF-group on day 2 whereas maximum saline-induced pain was 6.8±.3cm (10-cm visual analog scale). The difference in centroid position of force direction relative to day 0 was greater in the NGF group than in the control group (P<.05) on day 2 (before saline-induced pain) and day 4, reflecting changes in tangential force direction used to achieve the task. During saline-induced pain in both groups, tangential and task-related force variation was greater than before and after saline-induced pain (P<.05). Persistent movement-evoked pain changes force direction from the pain-free direction. Acute pain leads to increased variation in force direction irrespective of persistent movement-evoked pain preceding the acutely painful event. These differences provide novel insight into the search for and consolidation of new motor strategies in the presence of pain.

Stress Distribution of Bolted Joints With Different Lay-Up Types

A parametric study of the stress distribution in the composite plates is undertaken to show the effect of different lay-ups. Full 3-D elastic properties are required in the modelling. These properties are calculated using equations taken from the literature and derivation from simple Classical Laminate Plate Theory (CLPT). In previous experimental work, it was shown that tensile failure involved the development of a damage zone at the edge of the hole. In a double-lap joint, it is assumed that uniform stresses are exhibited throughout the plate thickness. Different lay-ups system give different tangential stress distributions and insignificant variation in the radial stress distribution along the hole boundary.

Flamelet characteristics at the leading edge and through the flame brush of statistically steady incompressible turbulent premixed flames

Conditional analysis is performed on statistical behavior of the flamelet characteristics at the leading edge and through the flame brush of incompressible turbulent premixed flames. The effective Lewis number is equal to unity with no stretch effect associated with differential diffusion. It is shown that the flamelet thickness, δf, is a crucial parameter to determine the local displacement speed, Sd, as well as the global turbulent burning velocity, ST. There hold asymptotic relationships for ST and conditional velocities at the leading edge in the statistically steady state. Sd is correlated with finite δf not in terms of stretch, but through independent effects of tangential strain rate and curvature. Sd and δf show strong correlations with curvature due to significant influence of tangential flux, while they show weak correlations dependent on the location in a flamelet with tangential strain rate. Flamelets tend to thicken according to the gradient of Sd due to focusing or defocusing of c transport for both positive and negative curvatures. The range of Sd is scaled by the tangential component, Sdt, with additional contribution of the normal Sdn component due to δf varying with curvature. Variation of Sdt is given in terms of the product of curvature and molecular diffusivity in the reaction–diffusion layer retaining a relatively invariant structure under turbulence. The stretched laminar flamelet model needs to be complemented by the additional effects of tangential flux and variation of finite δf in fully turbulent premixed flames.

Variation of Shrinkage in Relation to Anatomical Properties and age of Selected Bamboo Species, Bambusa bambos (L.) Voss and Dendrocalamus strictus Nees

Bamboo species is widely used for different purposes in the different parts of World. The variation in properties of the culms of bamboos are affected its use. Shrinkage is one of the physical properties in bamboo and it will affect the products. In this article deals with the variation in shrinkage at different height levels of bamboo culms, different portion in bamboo culms such as outer to inner variation, variation in different age groups of bamboo culms. In addition to this tangential and radial variation in shrinkage also studied. The result shows that a uniform trend in variation was observed based on different parameters.

Modeling far-field radio-frequency sheaths in Alcator C-Mod

This paper is motivated by the recent measurement of large (>100 V) plasma potentials in Alcator C-Mod during ion cyclotron range of frequency (ICRF) heating. The plasma potential is measured on field lines that intersect a limiter but do not pass near a powered ICRF antenna. The measured potential correlates with the local ICRF fast wave electric field and is a prime candidate to cause increased Mo sputtering from the limiter surface. In this paper, it is shown that a theory of ‘far-field’ radio-frequency (rf) sheaths can qualitatively explain this experimental observation. The theory describes rf-sheath formation when unabsorbed fast ICRF waves are incident on a conducting boundary far from the antenna. It is shown that the rf-sheath drive is sensitive to the angle between the surface normal and the equilibrium magnetic field. The main conclusion of this work is that the rapid tangential variation in the B field-limiter geometry near the tip of the limiter promotes the formation of large sheath potentials of the same order as the measured ones.

A finite-element approach in order to avoid ill-conditioning in thin-sheet problems in frequency domain—Application to magneto-quasistatics

In this work, a new thin-sheet approach in the finite-element method is derived. The focus is on the condition number of the system matrix, namely, to keep this measure preferably independent of the thickness of the sheet. Constant sheet elements are used for the tangential variation in the sheet. However, the information about the discontinuity in normal direction is incorporated into the basis functions of the volume elements that are connected to the sheet elements. The determination of the normal variation can be reduced to a 1D problem which can be solved analytically. No double layers or global asymptotic expansions are required. The advantages with respect to the condition number of the system matrix are shown for a magneto-quasistatic test scenario.

Directionality of Tangential Force Variation in High Speed Uniformity

Abstract Tire nonuniformity may affect vehicle ride comfort quality especially while vehicles are running at highway speeds. Spindle force variations in the radial, tangential, and lateral directions are normally used as parameters evaluating tire high speed uniformity performance. An interesting physical phenomenon—directionality of tangential force variation has been observed for many tires. The directionality of tangential force variation means that tangential force variation is different when a tire is measured in the clockwise and counter-clockwise directions under the same test conditions. In this paper, a theory is developed to explain the interesting physical phenomenon. Simulation and analysis are conducted using a dynamic tire model. It is found that the directionality of tangential force variation is caused by the interaction of different types of nonuniformities in tires such as mass and geometry variations.

The tangential variation of a localized flux-type eigenvalue problem

In this work the differentiability of the principal eigenvalue λ = λ 1 ( Γ ) to the localized Steklov problem − Δ u + q u = 0 in Ω, ∂ u ∂ ν = λ χ Γ ( x ) u on ∂ Ω, where Γ ⊂ ∂ Ω is a smooth subdomain of ∂ Ω and χ Γ is its characteristic function relative to ∂ Ω, is shown. As a key point, the flux subdomain Γ is regarded here as the variable with respect to which such differentiation is performed. An explicit formula for the derivative of λ 1 ( Γ ) with respect to Γ is obtained. The lack of regularity up to the boundary of the first derivative of the principal eigenfunctions is a further intrinsic feature of the problem. Therefore, the whole analysis must be done in the weak sense of H 1 ( Ω ) . The study is of interest in mathematical models in morphogenesis.

Effects of the Leakage Flow Tangential Velocity in Shrouded Axial Compressor Cascades

Although compressor blades have long been shrouded for aerodynamic and structural reasons, the importance of the leakage flow in the shrouded axial compressor has been investigated recently. However, the effects of the leakage tangential velocity variation on the blade passage flow are unknown. Therefore, this paper presents an experimental investigation of the loss and flow turning in the blade passage in shrouded axial compressor cascades subject to the variation of the leakage tangential velocity. The newly found results are as follows. First, increasing the leakage tangential velocity reduces overall loss up to 32.6% compared to the reference case. Second, increasing the leakage tangential velocity spreads loss core in the pitch-wise direction so loss core becomes more two-dimensional. Third, increasing the leakage tangential velocity makes the near hub passage flow more radially uniform.

Tangential and radial shrinkage variation within trees in sugi (Cryptomeria japonica) cultivars

The transverse shrinkage variation within trees was examined for five sugi cultivars. The within-tree trends of tangential shrinkage (α T) were different by cultivar, whereas radial shrinkage (α R) increased from pith to bark in most cultivars. The tangential/radial shrinkage ratio (α T/α R) decreased from pith to bark in most cultivars, because the radial variation of α R was larger than that of α T. The cultivars showed significant differences among cultivars in α T, α R, and α T/α R, but the difference among cultivars for α T/α R was smaller. The relationships between transverse shrinkage and microfi bril angle (MFA), basic density (BD), tree ring parameters, and modulus of elasticity were examined. The α T and α R showed positive relationships with BD, latewood percentage, latewood density, and modulus of elasticity, and negative relationships with MFA and ring width. The relationships with earlywood density were weak. Sugi exhibited variation in transverse shrinkage within stem and among cultivars, with the variation affected by MFA, density, and tree ring parameters.

Analysis of Disturbance on Differential Push–Pull Tracking with Dual-Layer Optical Disc

In this paper, we analyze the disturbance of tracking error signal caused by layer cross talk on playback of a dual-layer disc. We will reveal the origin of the disturbance by experiments using a special disc. The origin is the groove of the cross-talk layer. Furthermore, we will investigate other related factors that increase the disturbance. Tangential tilt and variation of space layer thickness in one revolution are such factors.

Tangential force variation due to the bogie direction reversal procedure

A range of tangential forces is generated within the contact patch when a wheelset moves on the rail. These forces are intensified when incorporating curved tracks and motored axle rail vehicles [Arrus, P., de Pater, A.D. and Meyers, P., 2002, The stationary motion of a one-axle vehicle along a circular curve with real rail and wheel profiles. Vehicle System Dynamics, 37(1), 29–58]. The wheelset is subject to flange contact if an unbalanced force remains in a curve towards the high rail gauge face. The resultant force in the transverse direction includes the lateral force, the radial force, and the creep forces in addition to the effect of the frequent wheelset displacement due to the kinematic oscillation [Iwnicki, S., 2003, Simulation of wheel–rail contact forces. Fatigue Fracture Engineering Material Structure, 26, 887–900]. This article has focused on a potential variation in some of the forces cited when the wheelset is subject to backward and forward movements. A severe wear rate observed within the wheel flange region in Iranian Railways was investigated by operating a test bogie on a curvaceous track. An obvious improvement in the wear rate and wear pattern of the wheels was attained when the second test bogie encountered a bogie direction reversal procedure. This enhancement is considered in this article from the force analysis standpoint.

Differences between sliding semi‐landmark methods in geometric morphometrics, with an application to human craniofacial and dental variation

Over the last decade, geometric morphometric methods have been applied increasingly to the study of human form. When too few landmarks are available, outlines can be digitized as series of discrete points. The individual points must be slid along a tangential direction so as to remove tangential variation, because contours should be homologous from subject to subject whereas their individual points need not. This variation can be removed by minimizing either bending energy (BE) or Procrustes distance (D) with respect to a mean reference form. Because these two criteria make different assumptions, it becomes necessary to study how these differences modify the results obtained. We performed bootstrapped-based Goodall's F-test, Foote's measurement, principal component (PC) and discriminant function analyses on human molars and craniometric data to compare the results obtained by the two criteria. Results show that: (1) F-scores and P-values were similar for both criteria; (2) results of Foote's measurement show that both criteria yield different estimates of within- and between-sample variation; (3) there is low correlation between the first PC axes obtained by D and BE; (4) the percentage of correct classification is similar for BE and D, but the ordination of groups along discriminant scores differs between them. The differences between criteria can alter the results when morphological variation in the sample is small, as in the analysis of modern human populations.

The tangential variation on hyperruled surfaces

One of the most interesting and profound aspects of classical differential geometry is its interplay with the calculus of variations. In fact, the main differential geometric ideas of the calculus of variation occur over and over again and are continually being invented and rediscovered in a vast array of classical and modern differential geometry. So the normal variational problem on general surfaces and hyperruled surfaces were studied by some geometers, specifically one may cite, in this regard, the works of Abdel-All and Abd-Ellah [Chaos, Solitons & Fractals, in press; Ind. J. Pure Appl. Math., in press; Adv. Model. Anal. 37 (2000)], Abdel-All and Hussien [J. Korean Math. Soc. 3 (1999) 663], Chen [J. Lond. Math. Soc. 6 (1973) 321; Total Mean Curvature and Submanifolds of Finite Type, World Scientific Publishing copre Ltd, 1984; Geometry of Submanifolds, Marcel Dekker, New York, 1973], Soliman et al. [Bull. Fac. Sci., Assiut Univ. 24 (1995) 189], Willmore [Total Curvature in Riemannian Geometry, Ellis Horwod Limited Publishers, 1982]. The purpose of the present work is to study effectiveness the tangential variation in the direction of the tangent for the base curve of hyperruled surfaces in E n+1 .