简支矩形复合材料薄板压缩屈曲后的极限强度

本文通过283块简支矩形玻璃钢薄板的压缩屈曲后极限强度的试验,证明了复合材料薄板在屈曲失稳后仍能继续承载,以玻璃钢为例,可以超过临界载荷的十几倍。文中对薄板的极限强度进行了大挠度和小挠度理论分析,结合复合材料的能量强度理论,最后得出有关极限强度计算公式的C参数曲线,对于45°方向的薄板与试验结果较符合,对于经纬向薄板当β<0.11时比试验结果略大。文中给出的C参数可供产品设计时参考。     

蜂窝夹层板的极限强度

蜂窝夹层板是由薄板元件(面板、蜂壁)组成的类似工字梁受力原理的结构元件。其局部失稳型式可分为三类:皱曲型,剪切型、酒窝型。皱曲型失稳型的理论分析,是把面板当作弹性基础上的薄板进行了局部稳定性分析,进一步考虑面板的初波纹度,剪切变形,求出芯子及胶层中的应力,然后按莫尔强度理论求出芯子或胶层破坏时的面板极限强度。为了便于比较和应用,面板极限强度的计算公式简化为K~3(E_fE_cC_c)~(1/2)的形式。     

玻璃钢及蜂窝夹层的高频介电性能

玻璃钢的介电常数和介电损耗角正切都比较小,是良好的透波材料.为了对这方面的性能更好地进行研究,减少试验工作量,以便更好地进行蜂窝夹层结构透波率的最优设计,必须对此性能进行理论研究,求出有实用价值的计算公式.现将我们进行的工作介绍如下. 一、玻璃钢的高频介电性能 玻璃钢的介电性能与原材料的介电性能有密切关系,一些原材料的介电性能列于表1[1,2]. 通常非极性聚合物(如聚乙烯、聚苯乙烯等)的介电性能数据比较低,6为2-2.4,tgδ为0.0003以下. 玻璃的介电性能数据随着含碱量减少而降低,因此一般采用含碱量少的无碱玻璃纤维.1.玻璃钢…     

BUCKLING TEST AND OPTIMUM DESICN OF FIHED REINFORCED COMPOSITE PLATES UNDER COMPRESSION

In this paper,the conelusion that the expermiental results coineide with theoretical analysis has been got(?)test of(?)coniposite(?)plates.It is confirmed that the(?)loads of(?)buckling theoretieal formula of(?)plate are reliable.The(?)of optinial(?)tent of matrix and optimal off-axis which make(?)composite phaes eachbiggest critical loads are also discussed(?)paper the(?)of(?)beused in the design for the products.     

SELECTION OF THE OPTIMUM PARAMETERS FOR SANDWICH CONSTRUCTION WITH HONEYCOMB CORE

The minimum weight of sandwich construction which is regarded as objective functionhas been discussed.Under given constraint condition of the strength or the stiffnessthe four optimum paramters of sandwich construction with honeycomb corethickness of the face t_f,thickness of the honeycomb core h_c.thickness of thehoneycomb wall t_s,side length of the honeycomb cell c(?) are evaluated,By usingconstraint condition of the strength,a equation of high degree is finally solved.In theconstraint condition of the stiffness,the constraint optimization problem is treated asinconstraint optimization problem with the method of obtaining extreme value solution byundetermined parameter multiplication.Also.the results are discussed.     

OPTIMUM DESIGN OF ADHESIVE BONDING OFRESIN-BASE COMPOSITES

I.IntroductionThemajorityofproductsofthefiberreinforcedcompositemateria1sareinthin-walIstructure.Themeritsofcompositesmaybefullyplayedbytheadhesivebonding.Theadhesivebondinghasfollowingadvantages:a.thejointofthesameordifferentkindsofmaterialsmayberealized…     

Selection of the optimum parameters for sandwich construction with honeycomb core

The minimum weight of sandwich construction which is regarded as objective function has been discussed. Under given constraint condition of the strength or the stiffness, the four optimum parameters of sandwich construction with honeycomb core (thickness of the face t_f, thickness of the honeycomb core h_c, thickness of the honeycomb wall t_s, side length of the honeycomb cell c) are evaluated. By using constraint condition of the strength, a equation of high degree is finally solved. In the constraint condition of the stiffness, the constraint optimization problem is treated as inconstraint optimization problem with the method of obtaining extreme value solution by undetermined parameter multiplication. Also, the results are discussed.     

Ultimate strength of postbuckling for simply supported rectangular composite thin plates under compression

1.IntroductionAsiswellthnown,thepostbucklingmetalplatescanbesuccessivelysubjectedtotheload.Forsomemetalplates,theultimatestrengthcanreachthirtytimesofthebucklingstressll].Inordertostudythebearingcapacityofthecompositeplatesthroughtestsandtheoreticalanalysis,f'ttiluretestsofthe283specimensofGFRPthinrectangularplatesundercompres.sionarecarriedout.ItisprovedthattheGFRPplatesinpostbucklingstillhavehigherbearingcapacity,forthetestedspecimensshowedultimatestrengthwhichisfourtotwenty-livetiniesth…     

蜂窝夹层结构的最优参数选择

本文把夹层结构的最轻重量作为目标函数,在给定的强度和刚度的约束条件下,求出蜂窝夹层结构的四个最优参数(面板厚度t_f,蜂窝芯子厚度h_c,蜂壁厚度t_s,蜂格边长c).在强度约束条件时,最后求解一个高次方程.在刚度约束条件时,用待定参数求极值的方法把约束极值问题化为无约束极值问题.文中对结果也进行了讨论.     

Buckling test and optimum design of fiber reinforced composite plates under compression

In this paper, the conclusion that the experimental results coincide with theoretical analysis has been got through buckling test of 283 composite rectangular plates. It is confirmed that the critical loads of composite plates calculated by buckling theoretical formula of anisotropic plate are reliable. The selections of optimal content of matrix and optimal off-axis which make fiber reinforced composite plates reach biggest critical loads are also discussed in this paper. The result of analysis may be used in the design for the products.