Based on the scalar diffraction theory and the boundary condition of rayleigh - sommerfeld , the accurate on - axis propagating wave function of plane wave diffracted by small circular band is obtained by solving the first integral of rayleigh - sommerfeld 摘要從標(biāo)量衍射理論出發(fā),采用瑞利索末菲衍射邊界條件,通過求解第一類瑞利索末菲衍射積分得到平面波經(jīng)圓環(huán)衍射后軸上的波函數(shù),進(jìn)而分析軸上的光強(qiáng)特性以及光強(qiáng)極值數(shù)量、位置和大小與衍射圓環(huán)內(nèi)外孔徑的關(guān)系。
Furthermore , the fiber volume fraction of each inclined and horizontal unidirectional " lamina was assumed to be the same as that of the composites . three - dimensional stress - strain analysis was applied to each unidirectional lamina that was assumed to be transversely isotropical under on - axis coordinate system . carrying out the integration and averaging of stiffness yielded the effective elastic moduli of 3 - d braided structural composites 采用三維應(yīng)力?應(yīng)變分析,在單胞的長(zhǎng)度方向積分和平均,在給定的應(yīng)變邊界條件下,采用剛度體積平均的方法,預(yù)測(cè)三維編織結(jié)構(gòu)復(fù)合材料的有效彈性模量;在空間多向應(yīng)力的基礎(chǔ)上,通過對(duì)三維編織結(jié)構(gòu)復(fù)合材料破壞機(jī)理的探討,摘要提出了適用于三維編織復(fù)合材料細(xì)觀強(qiáng)度失效準(zhǔn)則,預(yù)測(cè)三維編織結(jié)構(gòu)復(fù)合材料的強(qiáng)度性能。
A simply and analytical formula of the axial light intensity distribution behind a circular aperture is derived by using the helmhotz - kirchhoff integral theorem and the kirchhoff ' s boundary conditions . it is studied the nonparaxial on - axis intensity distribution throughout the whole space behind a circular aperture . an accurate formula to calculate the fresnel number of circular aperture is presented and the validity of usual fresnel number formula is reexamined . by using the analytical formula and diffraction integral formula , some numerical simulation comparisons are done , and it is shown that the results of the two methods are completely coincident 用亥姆霍茲-基爾霍夫積分定理和基爾霍夫邊界條件,推導(dǎo)出了平面波經(jīng)小圓孔非傍軸衍射時(shí)軸上強(qiáng)度的簡(jiǎn)單解析表達(dá)式,研究了平面波經(jīng)小圓孔后整個(gè)衍射空間非傍軸的軸上光強(qiáng)分布.給出了計(jì)算圓孔菲涅爾數(shù)的精確公式,重新檢查了通常的菲涅爾數(shù)公式的有效性.數(shù)值計(jì)算顯示,應(yīng)用解析表達(dá)式所得的結(jié)果與應(yīng)用衍射積分公式所得的結(jié)果完全一致
With the typical on - axis fatigue tests to get the relative s - n curves of unidirectional laminates , executed at certain stress ratio , it is possible to predict the fatigue life of multidirectional laminates subjected to cyclic stresses of different stress ratios . this would tremendously reduce test costs for laminate structures 考慮了層壓板中單向?qū)用鎯?nèi)多軸應(yīng)力和平均應(yīng)力的影響,在已知單向板在確定應(yīng)力比下受典型單軸循環(huán)應(yīng)力的s - n曲線的基礎(chǔ)上,預(yù)測(cè)任意鋪疊次序?qū)訅航Y(jié)構(gòu)在不同應(yīng)力比的循環(huán)載荷下的疲勞壽命。
Based on the hybrid / mixed element method of piezoelectric laminated , a piezoelectric multilayer element is developed , in the piezoelectric multilayer element , the continuity of transverse stresses of at interfaces between layers is naturally ensured . 3 . by the use of iso - function method , stress modes of 8 - node three - dimensional solid element made of on - axis orthotropic material are derived 依據(jù)一般層合板雜交元理論知識(shí),提出一個(gè)壓電層合板多層單元,利用壓電層合板子層間的表面參數(shù),使壓電層合板的層間應(yīng)力的連續(xù)性得到自然滿足,并對(duì)壓電層合板進(jìn)行雜交元列式。