Simplified Model Test Research Articles

角形鋼管柱・H形はり接合部の局部耐力推定式 : 角形鋼管柱溶接接合部の実験的研究2

The paper examines the local failure of welded RHS-column to H-beam connections with exterior diaphragm in rigid steel frames. Based on a number of simplified model test results reported in the previous paper (Ref. 1), the empirical formulae predicting the local strength of connections are derived by the dimensional analysis and the regression analysis. The empirical formulae obtained here are as follows : For the maximum load, [numerical formula]…(4) For the yield load, P_<cy>=0.58 P_<cmax>…(5) The limits of application are : B/T=22〜67, h_D/B≦0.2, t/T=0.75〜2.0 The proposed formulae are applicable to the following connections. 1) Connections fabricated by high strength steel grade SM 50 A or SM 58 Q. 2) Connections stiffened by triangular plates. 3) Connections subjected to tension or compression load on one side only. The strength of actual RHS-column to H-beam connections are predicted by the proposed formulae with sufficient accuracy by substituting Pc for M/(d-t). For RHS fabricated by four steel plates, the proposed formulae overestimate the strength of the connections by 20%.

鋼管柱・H 形はり接合部の耐力推定式 : 鋼管柱溶接接合部の研究 II

The present paper is on the local failure of tubular column to H-beam connections stiffened with ring stiffeners. On the basis of the test results reported in the preceeding paper (Ref. 1) which described a number of simplified model tests of the connections, the empirical formulae predicting the local strength of connections are derived by the dimensional analysis and the regression analysis. The empirical formulae obtained here are as follows : For the maximum load, [numerical formula]…(4) For the yield load, P_<cy>=0.65P_<cmax> The relationships between the value calculated from Eq. (4) and the test results are shown in Fig. 3. The limitations for using these formulae are D/tp=18〜54, h_s/R=0.14〜0.42, t_s/t_p=0.75〜2.25 and B_f/D=0.35〜0.63, and where the material properties of the ring stiffener and beam flanges are nearly equal to those of the tubular columns. In the practical connections, P=M_b/H_b shall be used.

Liquefaction Potential And Drag Force Acting On Piles In Flowing Soils

A large-scale shaking table test has been carried out to investigate the dynamic behavior of a pile model set in flowing soils induced by soil liquefaction. Furthermore, simplified model tests have been conducted to clarify the relation between liquefaction potential and the drag force acting on piles in flowing soils. Experimental results on the relation between liquefaction potential: excess pore water pressure ratio and external force loading on piles by flowing liquefied soils: drag force are discussed.

Use of Helium and Steam in Acoustic Scale Model Jets

It is postulated that design of a valid acoustic model to simulate jet engine exhaust need consider only three exhaust gas parameters: Mach number, density, and velocity. This provides a logical basis for a simplified model testing technique which uses a convenient working medium other than that of the full-scale engine. Operation at reduced temperatures is the major benefit. The design of experiments using steam and helium as the working media to simulate military and afterburning conditions of a jet engine, respectively, is described. The experimental results of these tests and corresponding tests performed with heated air jets support the postulation. Conclusions concerning future applications of this technique are discussed. (This work has been supported by U. S. Air Force contract.)