• Physical Therapy Rehabilitation Science
• /
• v.9 no.3
• /
• pp.191-196
• /
• 2020

Objective: Congenital muscular torticollis (CMT) is a disease with abnormal head and neck posture in infants. It affects the child's movement and development and can lead to complications. Therefore, this study aims to find out what factors influence the rehabilitation treatment duration of infants with CMT. Design: Cross-sectional study. Methods: The subjects were 63 infants under 90 days of age who were diagnosed with CMT. Age, thickness of the sternocleidomastoid muscle (SCM) on the affected and non-affected side, head tilt angle, and head rotation angle of the affected head in infants were collected. The ratio of muscle thickness was calculated from the thickness of the affected SCM and the thickness of the non-affected SCM (A/N ratio). All subjects underwent conservative physical therapy twice a week for 30 minutes, and the end of the treatment was when the angle of head tilt was normal or less than 5 degrees, and the treatment duration was calculated. Results: Age, thickness of affected SCM, and head tilt were significantly correlated with treatment duration (p<0.05). The thickness of the non-affected SCM, A/N ratio, and head rotation angle did not show any correlation with treatment duration. The factors affecting the treatment duration were head tilt and age, showing 21% explanatory power of adjusted R². Conclusions: The main factors affecting the treatment duration of infants with CMT are head tilt and age. Therefore, more attention should be directed to the infant's head tilt and age for effective physical therapy of infants with CMT.

• Structural Engineering and Mechanics
• /
• v.71 no.5
• /
• pp.459-467
• /
• 2019

In this paper, hyperbolic shear deformation theory is used for free vibration analysis of piezoelectric rectangular plate made of porous core. Various types of porosity distributions for the porous material is used. To obtain governing equations of motion, Hamilton's principle is used. The Navier's method is used to obtain numerical results of the problem in terms of significant parameters. One can conclude that free vibration responses are changed significantly with change of important parameters such as various porosities and dimensionless geometric parameters such as thickness to side length ratio and ratio of side lengths.

• Smart Structures and Systems
• /
• v.15 no.6
• /
• pp.1569-1582
• /
• 2015

Two hyperbolic displacement models are used for the bending response of simply-supported orthotropic laminated composite plates resting on two-parameter elastic foundations under mechanical loading. The models contain hyperbolic expressions to account for the parabolic distributions of transverse shear stresses and to satisfy the zero shear-stress conditions at the top and bottom surfaces of the plates. The present theory takes into account not only the transverse shear strains, but also their parabolic variation across the plate thickness and requires no shear correction coefficients in computing the shear stresses. The governing equations are derived and their closed-form solutions are obtained. The accuracy of the models presented is demonstrated by comparing the results obtained with solutions of other theories models given in the literature. It is found that the theories proposed can predict the bending analysis of cross-ply laminated composite plates resting on elastic foundations rather accurately. The effects of Winkler and Pasternak foundation parameters, transverse shear deformations, plate aspect ratio, and side-to-thickness ratio on deflections and stresses are investigated.

• Journal of the Korean Society of Costume
• /
• v.50 no.5
• /
• pp.117-130
• /
• 2000

The purpose of this thesis is to offer basic data for clothing design which is intended to apply appropriate shape and capacity to clothes. The following are the analyzed results of an investigation which was conducted to characterize the upper half of the female body of 193 women whose ages are 18 to 25, taking part in this investigation. According to the results of analyzing young women's bust, I came to find a large individual difference of the wide varying factor numbers at the items of the side feature, the body stance, and the dart quantity. For the analysis of the female's upper body, 11 factors are used. The are as follows: Factor 1. width of the bust Factor 2. height of the bust and length of the arm Factor 3. side thickness of the bust and the upside type Factor 4. length of the bust on the front Factor 5. length of the bust on the back Factor 6. salient ratio of the breast Factor 7. width of the neck. the armhole, and measurement of the droop Factor 8. length of the shoulder Factor 9. flat ratio of the bust Factor 10. inclination of the shoulder factor 11. form of the back The shape of young women's upper bodies can be divided into four groups. The character ization of each group are as follows : Group 1 . 28.5% of the women who take part in this investigation belong to Group 1 These women have the shortest body, with a longer length of the front than the back and more thickness on the front than the back. Group 2. 21.1% of the women who take part in this investigation belong to this group. They show a longer length of the back and more thickness of the back than the front. In addition, this group is bent forward. Group 3. This group is the mast common type, showing the shortest and thickest character. 37.8% of the women who take part in this investigation have this bust character Group 4. 12.4% of the women belong to Group 4. They possess the highest and fattest character, skewing smaller necks, armholes, and waists than the other groups. This group also shows the drooping shoulders.

• Journal of Ocean Engineering and Technology
• /
• v.5 no.1
• /
• pp.88-96
• /
• 1991

Fatigue life and retardtion behavior after through-thickness were examined experimentally by using a CT specimen and surface-cracked specimen. The material used was 3% Ni-Cr-Mo steel. The fatigue crack shape before through-thickness is almost semicircular, and the measured aspect ratio is larger than the value obtained by calculation using the K value proposed by Newman-Raju. It is found that the crack growth behavior on the back side after through-ghickness is unique and can be divided into three stages a, b and c. A retardation parameter has been used successfully to predict the growth of cracks in specimen, and in this time, retardation factor is 4.3. By using the crack propagation rule considering on retardation state and the K value proposed by the authors, the remarkable crack growth behavior and the change in crack shape can be evaluated quantitatively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.11a
• /
• pp.562-566
• /
• 2006

Lightweight body can cause a low stiffness due to the decrease of panel thickness and reinforcing member. The other way, high stiffness body demands an increase of mass. Front pillar section area is decreased due to driver's visual field. Global vehicle stiffness is affected by stiffness distribution ratio between upper part and lower part at side body structure. This paper will describe a process used to evaluate the stiffness distribution ratio based on research of strain energy analysis of the tip rotation method. In addition, optimum design schemes are presented for high stiffness and lightweight body structure considering the investigated stiffness distribution ratio. In this way the designer will be aided by a defined design guide and a set of supporting tool to help him work towards a good design

• Smart Structures and Systems
• /
• v.19 no.4
• /
• pp.441-448
• /
• 2017

This paper uses the four-variable refined plate theory for the free vibration analysis of functionally graded material (FGM) rectangular plates. The plate properties are assumed to be varied through the thickness following a simple power law distribution in terms of volume fraction of material constituents. The theory presented is variationally consistent, does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. Equations of motion are derived from the Hamilton's principle. The closed-form solutions of functionally graded plates are obtained using Navier solution. Numerical results of the refined plate theory are presented to show the effect of the material distribution, the aspect and side-to-thickness ratio on the fundamental frequencies. It can be concluded that the proposed theory is accurate and simple in solving the free vibration behavior of functionally graded plates.

• Journal of Ocean Engineering and Technology
• /
• v.13 no.2 s.32
• /
• pp.51-57
• /
• 1999

In this study, one side fillet welded T-joint, used in box type girder and other welding structure, was investigated by stress analysis and bending fatigue test without edge preparation, with variation of joint shape. The purpose of this study is to give the welding condiltion and design standard on manufacturing one side fillet welded T-joint. As a result, the following conclusions were obtained. 1) In one side fillet welded T-joint, the larger the leg length and the penetration depth, the greater the bending fatigue strength because reduction of stress and strain on toe and root. The increase of the longitudinal leg length rather than vertical leg length contributed to the increase in bending fatigue strength. 2) In one side fillet welded T-joint without edge preparation, both general manual welding and general automatic welding were carried out with same condition. In this case, automatic welding showed deeper penetration and more increased longitudinal leg length than manual welding, so that automatic welding offers greater bending fatigue strength. 3) For one side fillet welded T-joint without edge preparation with automatic welding, the ratio(h/t) of the leg length(h) and the main plate thickness(t) in which toe crake can occur was 1.0 over.

• Corrosion Science and Technology
• /
• v.16 no.4
• /
• pp.201-208
• /
• 2017

A finite element analysis is proposed to study the effect of specimen dimensions on lateral diffusion of hydrogen during hydrogen permeation flux measurements. The error of measurement on thick specimens because of 1D diffusion approximation may be as much as 70%. A critical condition for accurate measurements is to designate the area of hydrogen monitoring/exit surface smaller than the area of hydrogen charging/entry surface. For thin to medium thickness specimens (ratio of thickness to specimen radius of 5:10 and below), the charging surface should be maximized and the monitoring surface should be minimized. In case of relatively thick specimens (ratio of thickness to specimen radius above of 5:10), use of a hydrogen-diffusion barrier on the specimen boundaries is recommended. It would completely eliminate lateral losses of hydrogen, but cannot eliminate the deviation towards 2D diffusion near the side edges. In such a case, the charging surface should be maximized and the monitoring surface should be as closer in dimension as the charging surface. A regression analysis was carried out and an analytical relationship between the maximum measurement error and the specimen dimensions is proposed.

• Advances in nano research
• /
• v.12 no.2
• /
• pp.117-137
• /
• 2022

Effect of thickness stretching on free vibration, bending and buckling behavior of carbon nanotubes reinforced composite (CNTRC) laminated nanoplates rested on new variable elastic foundation is investigated in this paper using a developed four-unknown quasi-3D higher-order shear deformation theory (HSDT). The key feature of this theoretical formulation is that, in addition to considering the thickness stretching effect, the number of unknowns of the displacement field is reduced to four, and which is more than five in the other models. Two new forms of CNTs reinforcement distribution are proposed and analyzed based on cosine functions. By considering the higher-order nonlocal strain gradient theory, microstructure and length scale influences are included. Variational method is developed to derive the governing equation and Galerkin method is employed to derive an analytical solution of governing equilibrium equations. Two-dimensional variable Winkler elastic foundation is suggested in this study for the first time. A parametric study is executed to determine the impact of the reinforcement patterns, nonlocal parameter, length scale parameter, side-t-thickness ratio and aspect ratio, elastic foundation and various boundary conditions on bending, buckling and free vibration responses of the CNTRC plate.