Kun Cai, Zhen Luo and Qing H. Qin
The purpose of this paper is to develop a heuristic method for topology optimization of a continuum with bi-modulus material which is frequently occurred in practical engineering…
Abstract
Purpose
The purpose of this paper is to develop a heuristic method for topology optimization of a continuum with bi-modulus material which is frequently occurred in practical engineering.
Design/methodology/approach
The essentials of this model are as follows: First, the original bi-modulus is replaced with two isotropic materials to simplify structural analysis. Second, the stress filed is adopted to calculate the effective strain energy densities (SED) of elements. Third, a floating reference interval of SED is defined and updated by active constraint. Fourth, the elastic modulus of an element is updated according to its principal stresses. Final, the design variables are updated by comparing the local effective SEDs and the current reference interval of SED.
Findings
Numerical examples show that the ratio between the tension modulus and the compression modulus of the bi-modulus material in a structure has a significant effect on the final topology design, which is different from that in the same structure with isotropic material. In the optimal structure, it can be found that the material points with the higher modulus are reserved as much as possible. When the ratio is far more than unity, the material can be considered as tension-only material. If the ratio is far less than unity, the material can be considered as compression-only material. As a result, the topology optimization of continuum structures with tension-only or compression-only materials can also be solved by the proposed method.
Originality/value
The value of this paper is twofold: the bi-modulus material layout optimization in a continuum can be solved by the method proposed in this paper, and the layout difference between the structure with bi-modulus material and the same structure but with isotropic material shows that traditional topology optimization result could not be suitable for a real bi-modulus layout design project.
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The purpose of this paper is to analyze long-term institutional causes and consequences of preference falsification by studying the evolution of China’s patriarchal clan system.
Abstract
Purpose
The purpose of this paper is to analyze long-term institutional causes and consequences of preference falsification by studying the evolution of China’s patriarchal clan system.
Design/methodology/approach
The historic study shows that although the clan system was abolished in the Qin dynasty, it re-emerged among high-standing families in the Han dynasty and spread to common people after the Tang dynasty.
Findings
The author submits that the clan system was an institutional response to the preference falsification problem that arose due to the dictatorial political institutions first established in the Qin dynasty. It helped people to take collective action by themselves and also opened a back door to influence government decisions. A piece of clear evidence is the co-evolution of the clan system and government personnel system.
Social implications
In this sense, the clan system probably also helped to prolong the political institutions for 2,000 years.
Originality/value
This is the first institutional study on the clan system in China.
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According to the unique style and historical significance, Chinese ancient architecture which has a long history, plays an important role in world architecture. Most of Chinese…
Abstract
According to the unique style and historical significance, Chinese ancient architecture which has a long history, plays an important role in world architecture. Most of Chinese ancient architecture uses wooden frame as a load-bearing system, however, a unique combination of components has emerged in its development. Due to the well-preserved ancient buildings and a long historical and cultural background of Qijiang ancient town, the paper takes the Qijiang ancient town as an example through field measurement and investigation. The composition of the external environment of the building, architectural characteristics and building monomer composition were analyzed and studied. The unique architectural art charm of Qijiang ancient town was showed. Moreover, the delimitation of the protection scope mainly includes the scope of protected areas and the scope of the construction control zone. Among them, the protected areas are generally divided into key protected areas and general protected areas; the construction control zones are generally divided into Type I of construction control zone and Type II of construction control zones. Ancient buildings are the most existing heritage types in China and are an important part of the immovable cultural relics in China. The group layout of ancient buildings is an important feature in the layout of ancient buildings in China, which is conducive to the realization of the overall protection of heritage.
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Qing‐Sheng Yang, Cai‐Qin Cui and Xu‐Zhi Lu
The advanced synthetic and natural materials, such as piezoelectric ceramics, electroactive polymers and biological soft tissues, exhibit the multi‐physical or physicochemical…
Abstract
The advanced synthetic and natural materials, such as piezoelectric ceramics, electroactive polymers and biological soft tissues, exhibit the multi‐physical or physicochemical coupling behaviors. The coupling behavior involves the thermal‐mechanical, electric‐mechanical and electrochemicalmechanical interactions. The coupling phenomena can be modeled in the microscopic and macroscopic levels. In the microscale, the material consists of the solid, fluid and ions. The domain FE technique can be used to model the deformation of the solid and the flow of the fluid. In the macroscale, the mixture theory can be applied to description of the coupled response of the continuum under coupled thermal, electrical, chemical and mechanical loadings. A weak form of the governing equations is established by means of variational principle and a multi‐field finite element (MFE) method is developed for numerical modeling of the coupling behavior of advanced materials.
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Zhuo‐Jia Fu, Qing‐Hua Qin and Wen Chen
The purpose of this paper is to develop a hybrid‐Trefftz (HT) finite element model (FEM) for simulating heat conduction in nonlinear functionally graded materials (FGMs) which can…
Abstract
Purpose
The purpose of this paper is to develop a hybrid‐Trefftz (HT) finite element model (FEM) for simulating heat conduction in nonlinear functionally graded materials (FGMs) which can effectively handle continuously varying properties within an element.
Design/methodology/approach
In the proposed model, a T‐complete set of homogeneous solutions is first derived and used to represent the intra‐element temperature fields. As a result, the graded properties of the FGMs are naturally reflected by using the newly developed Trefftz functions (T‐complete functions in some literature) to model the intra‐element fields. The derivation of the Trefftz functions is carried out by means of the well‐known Kirchhoff transformation in conjunction with various variable transformations.
Findings
The study shows that, in contrast to the conventional FEM, the HT‐FEM is an accurate numerical scheme for FGMs in terms of the number of unknowns and is insensitive to mesh distortion. The method also performs very well in terms of numerical accuracy and can converge to the analytical solution when the number of elements is increased.
Originality/value
The value of this paper is twofold: a T‐complete set of homogeneous solutions for nonlinear FMGs has been derived and used to represent the intra‐element temperature; and the corresponding variational functional and the associated algorithm has been constructed.
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Check-Teck Foo, Weiwei Wu and Tachia Chin
The purpose of this paper is to utilize a multi-method design for research on corruption in China. Corruption in any society is inimical to good governance. Singapore, despite her…
Abstract
Purpose
The purpose of this paper is to utilize a multi-method design for research on corruption in China. Corruption in any society is inimical to good governance. Singapore, despite her size, is argued to be a plausible model for China.
Design/methodology/approach
Taking a multi-method approach, the phenomena of corruption is investigated from: etymological analyses for corruption (European roots) and its Chinese equivalent, 贪污 (pinyin: tan wu) case studies taken from three periods: current, Qing Dynasty and to founding of China (zhong guo, Qin Dynasty) to ground our policy recommendation of China be modeling after Singapore on the basis of our analysis of statistical (2013 and longitudinal) data. In the process, the authors embark on inter-country comparisons (mainly Confucian China, Hong Kong, Taiwan, South Korea and Japan).
Findings
Here are the key insights: scholars are unaware the English word corruption is narrower in scope than the Chinese equivalent tan wu贪污. As far back as 3,000 years, the Chinese had attributed wu, 污 as filthy, polluting, dirty to psychological concept of greed tan, 贪. In English, corruption does not denote greed per se. Falsification of facts as a political ploy dates back to Qin dynasty. Destabilizing corrupt cases occurred in China today as in Qing Dynasty. Singapore rather Hong Kong is a better model for China in reforming society.
Practical implications
This paper illustrates a distinctively, in-depth approach to research on Chinese management. It shows why it is important to clarify key concepts: corruption in the West and tan wu贪污in the East. Historical cases are utilized to show the presence of a continuing Chinese mind set. The authors argued for China to embark on a city-by-city strategy (modeling after Singapore) toward becoming a corruption-free society. Now, as 3,000 years ago, the Chinese conceptualization of corruption embeds the psychology of greed.
Social implications
China is at a crossroad of her economic development. There is a possible risk of China being destabilized through the corruption of the top rung of leadership. Chinese authorities must with urgency, rein in corruption. An approach is proposed in this paper.
Originality/value
In terms of style, approach and method of research, this paper is highly original. The integrative research here provides a rationale and basis for the Chinese leaders to implement a policy for a less corrupt society.
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Zhong Wu, Qing Hu, Zhenbo Qin, Yiwen Zhang, Da-Hai Xia and Wenbin Hu
Nickel-aluminum bronze (NAB) has been widely used in ship propellers. It is always subjected to local micro-plastic deformation in service environments. This paper aims to study…
Abstract
Purpose
Nickel-aluminum bronze (NAB) has been widely used in ship propellers. It is always subjected to local micro-plastic deformation in service environments. This paper aims to study the influence of plastic deformation on the mechanical strength and corrosion resistance of NAB in 3.5 Wt.% NaCl solution.
Design/methodology/approach
Scanning electron microscope and X-ray diffraction were used to analyze the microstructure of NAB alloy with different plastic deformations. Mechanical properties of the sample were measured by tensile experiment, and corrosion behavior was studied by electrochemical measurements and the long-term immersion corrosion test.
Findings
Results showed that the plastic deformation caused lattice distortion but did not change the microstructure of NAB alloy. Microhardness and yield strength of NAB were significantly improved with the increase of deformation. The lattice distortion accelerated the formation of corrosion product film, which made the deformed alloy show a more positive open-circuit potential and an increased Rp. However, during the long-term immersion corrosion, the corrosion resistance of NAB alloys deteriorated with the increase of plastic deformation. This is because larger plastic deformation brought about higher internal stress in corrosion product film, which resulted in the premature peeling of the film and the loss of its protective effect on the alloy substrate.
Originality/value
Tensile plastic deformations were found to cause a decline in the corrosion resistance of NAB. And the mechanism was clarified from the evolution of corrosion products during the corrosion process.
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Qing Jiang, Yuhang Wan, Xiaoqian Li, Xueru Qu, Shengnan Ouyang, Yi Qin, Zhenyu Zhu, Yushu Wang, Hualing He and Zhicai Yu
This study aims to evaluate the thermal performance of sodium alginate (SA) aerogel attached to nano SiO2 and its radiative cooling effect on firefighting clothing without…
Abstract
Purpose
This study aims to evaluate the thermal performance of sodium alginate (SA) aerogel attached to nano SiO2 and its radiative cooling effect on firefighting clothing without environmental pollution.
Design/methodology/approach
SA/SiO2 aerogel with refractory heat insulation and enhanced radiative cooling performance was fabricated by freeze-drying method, which can be used in firefighting clothing. The microstructure, chemical composition, thermal stability, and thermal emissivity were analyzed using Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analyzer and infrared emissivity measurement instrument. The radiative cooling effect of aerogel was studied using thermal infrared imager and thermocouple.
Findings
When the addition of SiO2 is 25% of SA, the prepared aerogel has excellent heat insulation and a high radiative cooling effect. Under a clear sky, the temperature of SA/SiO2 aerogel is 9.4°C lower than that of pure SA aerogel and 22.1°C lower than that of the simulated environment. In addition, aerogel has more exceptional heat insulation effect than other common fabrics in the heat insulation performance test.
Research limitations/implications
SA/SiO2 aerogel has passive radiative cooling function, which can efficaciously economize global energy, and it is paramount to environment-friendly cooling.
Practical implications
This method could pave the way for high-performance cooling materials designed for firefighting clothing to keep maintain the wearing comfort of firefighters.
Originality/value
SA/SiO2 aerogel used in firefighting clothing can release heat to the low-temperature outer space in the form of thermal radiation to achieve its own cooling purpose, without additional energy supply.
Graphical abstract
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Yesen Zhu, Cheng-Qing Gu, Jinliang Wang, Xiaohui Xi and Zhenbo Qin
The purpose of this paper is to study the effect of chromium content on the microstructure and corrosion resistance of Ni-Cr coating.
Abstract
Purpose
The purpose of this paper is to study the effect of chromium content on the microstructure and corrosion resistance of Ni-Cr coating.
Design/methodology/approach
Ni-Cr coating was prepared by pulse current electrodeposition with trivalent chromium. On the basis of studying effect of electroplating parameters on composition and morphology, Ni-Cr alloy coatings with various chromium contents were obtained. The microstructure was characterized by scanning electron microscopy, X-ray diffractometer and transmission electron microscopy. Corrosion behavior was studied by potentiodynamic polarization and electrochemical impedance spectroscopy techniques.
Findings
Electrodeposited chromium was solidly dissolved in nickel and refined the grain of the coating. With the increase of Cr content, the corrosion resistance of Ni-Cr coating was enhanced, which is due to the formation of continuous nickel hydroxide and compact chromium oxide passive films.
Originality/value
Ni-Cr alloy coating without penetration crack was prepared in trivalent chromium electrolyte, and the mechanism of its excellent corrosion resistance was proposed.
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Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the…
Abstract
Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.