• Title/Summary/Keyword: refined higher order theory

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Fashion and Basic Apparel Goods in Merchandising Process (Part II) Planning, Production, and Presentation (의류 상품화 과정에서 패션 제품과 베이직 제품의 차이(제2보): 기획, 생산, 판매 과정)

  • 이유리
    • Journal of the Korean Society of Clothing and Textiles
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    • v.28 no.7
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    • pp.904-915
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    • 2004
  • Following the PART I, which explored the concept of 'Fashion Goods' and 'Basic Goods' in terms of design elements and operational differences, this study, PART II, examined the differences in merchandising process of the two different types of goods. Merchandising process was divided into three stages; planning, production, and presentation. The study adopted a qualitative approach by use of eighteen in-depth interviews with merchandisers and designers with a minimum of six years and a maximum of 15 years of career experience in apparel industry. According to the type of goods, different merchandising practices were found. Especially material and production order/reorder practices were noteworthy. Fashion goods had high possibility of using high-quality materials sourced abroad and few of them were reordered. In other words, reorder practices were established for basic goods only; replenishment was actively implemented for higher inventory turn of basic goods; usually materials and production for basic goods were sourced domestically. In conclusion, based on the differences, more refined merchandising strategies of apparel companies and consistent theory building in this field are required for fashion and basic goods respectively.

Nonlinear vibration of FG-CNTRC curved pipes with temperature-dependent properties

  • Mingjie Liu;Shaoping Bi;Sicheng Shao;Hadi Babaei
    • Steel and Composite Structures
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    • v.46 no.4
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    • pp.553-563
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    • 2023
  • In the current research, the nonlinear free vibrations of curved pipes made of functionally graded (FG) carbon nanotube reinforced composite (CNTRC) materials are investigated. It is assumed that the FG-CNTRC curved pipe is supported on a three-parameter nonlinear elastic foundation and is subjected to a uniform temperature rise. Properties of the curved nanocomposite pipe are distributed across the radius of the pipe and are given by means of a refined rule of mixtures approach. It is also assumed that all thermomechanical properties of the nanocomposite pipe are temperature-dependent. The governing equations of the curved pipe are obtained using a higher order shear deformation theory, where the traction free boundary conditions are satisfied on the top and bottom surfaces of the pipe. The von Kármán type of geometrical non-linearity is included into the formulation to consider the large deflection in the curved nanocomposite pipe. For the case of nanocomposite curved pipes which are simply supported in flexure and axially immovable, the motion equations are solved using the two-step perturbation technique. The closed-form expressions are provided to obtain the small- and large-amplitude frequencies of FG-CNTRC curved pipes rested on a nonlinear elastic foundation in thermal environment. Numerical results are given to explore the effects of CNT distribution pattern, the CNT volume fraction, thermal environment, nonlinear foundation stiffness, and geometrical parameters on the fundamental linear and nonlinear frequencies of the curved nanocomposite pipe.

On the snap-buckling phenomenon in nanocomposite curved tubes

  • Dan Chen;Jun Shao;Zhengrong Xu;Hadi Babaei
    • Structural Engineering and Mechanics
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    • v.89 no.1
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    • pp.13-22
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    • 2024
  • The nonlinear snap-through buckling of functionally graded (FG) carbon nanotube reinforced composite (CNTRC) curved tubes is analytically investigated in this research. It is assumed that the FG-CNTRC curved tube is supported on a three-parameter nonlinear elastic foundation and is subjected to the uniformly distributed pressure and thermal loads. Properties of the curved nanocomposite tube are distributed across the radius of the pipe and are given by means of a refined rule of mixtures approach. It is also assumed that all thermomechanical properties of the nanocomposite tube are temperature-dependent. The governing equations of the curved tube are obtained using a higher-order shear deformation theory, where the traction free boundary conditions are satisfied on the top and bottom surfaces of the tube. The von Kármán type of geometrical non-linearity is included into the formulation to consider the large deflection in the curved tube. Equations of motion are solved using the two-step perturbation technique for nanocomposite curved tubes which are simply-supported and clamped. Closed-form expressions are provided to estimate the snap-buckling resistance of FG-CNTRC curved pipes rested on nonlinear elastic foundation in thermal environment. Numerical results are given to explore the effects of the distribution pattern and volume fraction of CNTs, thermal field, foundation stiffnesses, and geometrical parameters on the instability of the curved nanocomposite tube.

3-D Free Vibration Analysis of Exponential and Power-law Functionally Graded Material(FGM) Plates (지수 및 멱 법칙 점진기능재료 판의 3차원 자유진동해석)

  • Lee, Won-Hong;Han, Sung-Cheon;Ahn, Jin-Hee;Park, Weon-Tae
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.5
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    • pp.553-561
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    • 2015
  • The exponential and power law functionally graded material(FGM) theory is reformulated considering the refined shear and normal deformation theory. This theory has ability to capture the both normal deformation effect and exponential and power law function in terms of the volume fraction of the constituents for material properties through the plate thickness. Navier's method has been used to solve the governing equations for all edges simply supported plates on Pasternak elastic foundation. Numerical solutions of vibration analysis of FGM plates are presented using this theory to illustrate the effects of power law index and 3-D theory of exponential and power law function on natural frequency. The relations between 3-D and 2-D higher-order shear deformation theory are discussed by numerical results. Further, effects of (i) power law index, (ii) side-to-thickness ratio, and (iii) elastic foundation parameter on nondimensional natural frequency are studied. To validate the present solutions, the reference solutions are discussed.