縦強力曲線の新作圖法
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概要
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The well known method of drawing the longitudinal strength curves-the shearing force curve and the bending moment curve-has been used heretofore without any basic improvement, inspite of its troublesome process. The authors propose here some fundamental modifications in the process, expecting to serve for saving time and labour to be spent in the work. The principle of the modification is based on the following two facts, i. e.(a) Strength curves are represented by the differences between the integral curves of bouyancy curve and of weight curve, in lieu of the integral curves of the corresponding load curve.(b) Required bouyancy curve can be derived from, by "interporating (or exterporating)" two approximate bouyancy curves fairly apart each other, so far as almost all the segments on the "Bonjean's curve" cut by corresponding two wave profiles are considered to be practically straight. The process of the new method is arranged as follows : -1. Integrate twice the weight curve W, taking the base line nearly at the mean height level.-to name the 1st. & 2nd. integral curves, W^^o & W^^<oo> respectively.2. Allocate an adequate position of the wave profile possibly match the distribution of the weight, and draw a bouyancy curve B_1 therefrom, and integrate it once taking the same base line in (1); we obtain B^^o_1.3. Build another probable bouyancy curve B_2,and the 1st. integral curve B^^o_2,adjusting the vertical position of wave with the aid of such a guide formula as given below.4. Interpora〓e (or exterporate) the two 1st. integral curves of bouyancy B^^o_1 & B^^o_2 so that the end point coincid s with that of the Ist. integral curve of weight W^^o, and integrate the resulting curve B^^o_2,then we obtain B^^<oo>_3.5. Construct moreover a new bouyancy curve B_4 and the Ist. integral curve B^^o_4,adjusting mainly the longitudinal inclination of wave with the guide formulae as mentioned below. Then interporate (or exterporate) the latter (B^^o_4) and the curve B^^o_1 or B^^o_2 so as to satisfy the end condition-thus B^^o_3 is obtained-and integrate it again, we obtain B^^<oo>_5. 6. Interporate (or exterporate) the two final curves B^^<oo>_3 & B^^<oo>_3 to result a new curve B^^<oo> having the end point jointed with the 2nd. integral curve of weight (W^^<oo>), the required 2nd. integral curve of bouyancy.7. Interporate (or exterporate) the intercept of the two curves B^^o_3 & B^^o_5 with the same ratio in (6), -thus the required 1st. integral curve of bouyancy (B^^o) is obtained. The intercept of the 1st. integral curve of weight (W^^o) and that of bouyancy (B^^o) represents the shearing force, and the same of the 2nd. integral curve of weight (W^^<oo>) and that of bouyancy (B^^<oo>), the bending moment.Schema of process.[numerical formula]note : -(i) d_s=mean height of wave's half-height line above keel ; for B_s. δ_s=half trim of " " " " at ends of L given below ; for B_s.(positive value corresponds to trim by stern) w^^o, w^^<oo>. b^^o_s & b^^<oo>_s=end point of W^^o, W^^<oo>, B^^o_s and B^^<oo>_s respectively. (sufix s=1,2…5)→ denotes to integra'e.} to interporate. ↓ to intercept. I, II, ……XII mark the order of procese.-VIII & VIII' are to be alternative ; XI is to interporate the intercept with the same ratio of X.(ii) Guide formulae for position of wave : -(crest or hollow being kept on a given vertical line)[numerical formula] in which, W=ship's displacement in metric tons. L=ship's length in metres. (corresronding to the length of weight curve) if we put, γ=integraph scale in cm. and drawing scale be 1cm=α m for length. 1 cm=β t/m for weight & bouyancy. then c=αβγ, =reading scale for shearing force curve. c'=α^2βγ^2=reading scale for bending moment curve. preferably, n & m are to be multiplied by 0.5+10k for sagging condition and 1.0+10k for hogging condion, where k=(wave beight)/(wave length)
- 社団法人日本船舶海洋工学会の論文
- 1942-11-30