力学大师S.P.铁木辛柯

S.P.铁木辛柯,20世纪活跃在工程力学领域约60年,培养了几代优秀的工程师和力学家,取得了丰硕的研究成果,推动了工程力学的进展,人们尊之为力学大师.本文从学术生涯、研究成果、学术著作、学术贡献几方面简介铁木辛柯.     

Measurement of thermal stresses in the S.S. “Boulder Victory”

A lack of comprehensive experimental measurements of thermal stresses induced in a ship's hull structure by diurnal temperature changes prompted this study. Its essential purpose was to provide reliable prototype measurements of thermal-stress patterns around a complete transverse section of a ship. These results are compared with stresses computed by the theory of simple beams under arbitrary temperature distributions across their section. Bridge-type SR-4 strain-gage assemblies were developed for attachment directly to the structure. A variety of temperature conditions were observed and corresponding strain measurements taken. The results are consistent and give a reliable picture of thermal-stress conditions in a ship. They also verify the prediction of thermal stresses afforded by the simple-beam theory.     

S.M.Bogdonoff教授在中国科学院力学研究所讲学

美国普林斯顿大学S.M.Bogdonoff教授于5月19日下午在力学所介绍了他们几年来在湍流边界层分离研究方面取得的进展和今后工作的展望。他们研究的主要对象是四种翼的典型外形(图1)在马赫数3和高雷诺数(10~7—10~8/米)来流条件下产生的激波湍流边界层干扰流场。研究内容主要是干扰流场的平均性质和干扰流场的非定常性。他们用煤油-烟黑油流      

USING GENERALIZED VARIATIONAL PRINCIPLES TO RESOLVE THE ST. VENANT’S TORSIONAL BAR WITH A CRACK

According to generalized variational principles suitable for linear elastic incompatible displacement elements given by Professor Chien Wei-zang, using crack tip singular element and isoparametric surrounding element given by the author of this paper, we will study the St. Venant’s torsional bar with a radial vertical crack and compare the present computed results with the results of reference [2], The present computed results show that, using the method provided in this paper, satisfactory convergent solution can be obtained under lower degree of freedom.     

USING GENERALIZED VARIATIONAL PRINCIPLES TO RESOLVE THE ST.VENANT’S TORSIONAL BAR WITH A CRACK

According to generalized variational principles suitable for linear elastic incompatibledisplacement elements given by Professor Chien Wei-zang,using crack tip singular elementand isoparametric surrounding element given by the author of this paper,we will study theSt.Venant’s torsional bar with a radial vertical crack and compare the present computedresults with the results of reference[2].The present computed results show that,using themethod provided in this paper,satisfactory convergent solution can be obtained under lowerdegree of freedom.     

A NOTE ON MORI-TANAKA＇S METHOD

Explicit expressions of Mori-Tanaka＇s tensor for a transversely isotropic fiber rein- forced UD composite are presented. Closed-form formulae for the effective elastic properties of the composite are obtained. In a 3D sense, the resulting compliance tensor of the composite is symmetric. Nevertheless, the 2D compliance tensor based on a deteriorated Mori-Tanaka＇s tensor is not symmetric. Nor is the compliance tensor defined upon a deteriorated 2D Eshelby＇s tensor. The in-plane effective elastic properties given by those three approaches are different. A detailed comparison between the predicted results obtained from those approaches with experimental data available for a number of UD composites is made.     

W.SHOCKLEY’S EQUATION AND ITS LIMITATION

The problem of p-n junction in Ref.[1] is discussed in thispaper.We consider that Tsai Shu-tang’s view that w.Shock-ley’s equation cannot be applied to all circumstances is cor-rect,but we cannot sag,because of this,that W.Shockley’smethod of treatment and its conclusion for p-n junction arewrong.In this paper we demonstrated that W.Shockley’s e-quation merely describes ideal p-n junction model.     

W.SKOCKLEY’S EQUATION AND ITS LIMITATION

The problem of P-n junction in Ref.[1] is discussed in this paper. We consider that Tsai Shu-tang’s view that W.Shock-ley’s equation cannot be applied to all circumstances is correct, but we cannot say, because of this, that W. Shockley’s method of treatment and its conclusion for P-n junction are wrong. In this paper we demonstrated that W. Shockley’s e-quation merely describes ideal P-n junction model.     

ON A GENERALIZATION OF BERTRAND’S THEOREM

Bertrand’s theorem for the determination of the applied forces to a holonomicsystem from one of its first integrals,is extended to nonholonomic systems.Someinteresting applications of this new result are also given.     

A. A. Il’yushin’s scientific heritage and development of his ideas in mechanics

We present a survey of the main results and scientific ideas due to the 20th century prominent scientist Aleksey Antonovich Il’yushin, which can be regarded today, at his hundredth birthday anniversary, as his scientific heritage. The survey material is arranged (mainly, chronologically) in the key directions of Il’yushin’s activities such as the theory of viscoplastic flow, hydrodynamic stability, dynamics of deformable media, supersonic aerodynamics and related flatter problems, theory of elastoplastic processes, theory of plastic flow, thermoviscoelasticity and thermodynamics, strength of polymer bodies and structures, general theory of constitutive relations in classical continuum mechanics, and nonclassical models of continuum.     

PNEUMATIC CONVEYING OF BIOMASS PARTICLES. A REVIEW

Processes involving biomass are of growing interest, but handling and conveying biomass particles are challenging due to the unusual physical properties of biomass particles. This paper reviews recent work on pneumatic conveying of biomass particles, especially agricultural particles and pulp fibres. Experimental work has been mainly carried out to determine a range of parameters, such as pressure drop, particle velocity, flow regime and electrostatic charging for both horizontal and vertical conveying. Models ranging from empirical to CFD models are also being developed. Difficulties in representing turbulence and interactions among biomass particles and between the particles and fluid have so far limited the success of advanced modeling. Further work is needed to improve understanding of multiphase biomass pneumatic conveying and to assist in the development of biomass energy and conversion processes.     

A SIGNIFICANT IMPROVEMENT ON NEWTON’S ITERATIVE METHOD

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A NOTE ABOUT ODEN’S CONSTITUTIVE VARIATIONAL PRINCIPLE

A remark about some unreasoning things of Oden’s constitutive variational principledescribed in Ref.[1]is given in this paper.According to Oden’s idea,the other twoconstitutive variational principles,which are complementary to one another,are developed.An example is performed to demonstrate the application of the constitutive variationalprinciples.