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61.
风灾防护系统对于保障军交运输安全具有重要意义。本文针对风灾防护系统应用的不足,开展了需求分析,进行了工作模块设计,并提出了预警模式判别方法和防护措施的设计。该系统的逻辑步骤和模块设计符合强风条件下行车安全多因素决定性的客观特征,其具有成本优势。 相似文献
62.
63.
64.
In this paper, field experimental comparison is made between a small track-type experimental prototype skidder and a J-50 skidding tractor. Experimental data, including skidding productivity, soil compaction on skidding trails, and damage rate of the residual trees, are analyzed. The results indicate that with the condition of scattered skidding area and low skidding volume per cycle, small track-type experimental prototype skidder has advantage on working and a higher skidding productivity. It makes lower soil compaction to the skidding trails in the depth of 0-5 cm, 5-10 cm, and 10-15 cm. Under the same work conditions, the damage rate of the residual trees made by small track-type experimental prototype skidder is only 1/5 of those made by J-50 type skidding tractor. The damage rate is reduced by 80%. 相似文献
65.
在斜面上布置管路时,虽然设计上满足了管子自重下滑力与其摩擦力的平衡,但工程实际中管子仍会下滑从而造成变形破坏。详细分析了破坏的原因,认为是由于温差引起管子在斜面上蠕动而造成的。 相似文献
66.
The paper addresses the analytical determination of vibrodiagnostic parameters that describe the presence of normal-rupture
flat through-the-thickness and surface semi-elliptical central cracks in a rectangular homogeneous plate of constant thickness
for various plate fixing conditions and vibration modes. It is shown that the most sensitive vibrodiagnostic damage parameter
of a plate is the variation of the logarithmic decrement in the case of a through-the thickness crack and the second-harmonic
ratio of the vibration process in superharmonic resonance in the case of a surface crack.
__________
Translated from Problemy Prochnosti, No. 5, pp. 27–47, September–October, 2006. 相似文献
67.
Pierre Ladevèze Gilles Lubineau David Violeau 《International Journal of Fracture》2006,137(1-4):139-150
A new computational damage micromodel for laminates, which takes into account classical experimental micro- and macro-observations
for various stacking sequences, is described. The first computational examples are shown. 相似文献
68.
The nanoindenting method is based on the automatic measurement and recording of the force acting on the indenter (10−2-5 N) and the depth of indentation (10−2-200 μm). The scratch hardness or nanoscratching method is based on the continuous recording of resistance forces to movement
of the indenter impressed into the surface.
__________
Translated from Problemy Prochnosti, No. 4, pp. 132–139, July–August, 2006. 相似文献
69.
M. G. Burke M. Watanabe D. B. Williams J. M. Hyde 《Journal of Materials Science》2006,41(14):4512-4522
The characterization of the solute-enriched features (clusters or nanoprecipitates in irradiated low-alloy steels) requires extremely high spatial and elemental resolution, previously necessitating analysis using atom probe field-ion microscopy. In this investigation, field-emission gun-scanning transmission electron microscope (FEG-STEM) quantitative energy dispersive X-ray (EDX) microanalysis (spectrum imaging) has been applied to the characterization of the irradiation-induced nanoprecipitates in a low-alloy forging steel. Refinements in the EDX data have been possible via the application of multivariate statistical analysis (MSA) to the spectrum images, resulting in significantly reduced noise in the images. Most importantly, MSA permitted the clear identification of other elements in these Ni-enriched nanoprecipitates—including Mn and Cu. The processed X-ray spectrum images also provided direct evidence of the preferential formation of these irradiation-induced features along pre-existing dislocations within the steel, as well as the formation of intragranular nanoprecipitates. This research has provided the first direct X-ray spectrum images of irradiation-induced nanoprecipitates in high Ni A508 Gr4N forging steel, and has demonstrated the significant improvements attainable though the application of MSA techniques to the spectrum images. These results independently confirmed the analyses of the Ni-enriched nanoprecipitates previously conducted by 3D-APFIM, with the performance of the FEG-STEM/EDX technique shown to be comparable to that of the 3D-APFIM technique. 相似文献
70.
A weight function-critical plane approach for low-cycle fatigue under variable amplitude multiaxial loading 总被引:1,自引:0,他引:1
X. CHEN D. JIN K. S. KIM 《Fatigue & Fracture of Engineering Materials & Structures》2006,29(4):331-339
Low‐cycle fatigue data of type 304 stainless steel obtained under axial‐torsional loading of variable amplitudes are analyzed using four multiaxial fatigue parameters: SWT, KBM, FS and LKN. Rainflow cycle counting and Morrow's plastic work interaction rule are used to calculate fatigue damage. The performance of a fatigue model is dependent on the fatigue parameter, the critical plane and the damage accumulation rule employed in the model. The conservatism and non‐conservatism of predicted lives are examined for some combinations of these variables. A new critical plane called the weight function‐critical plane is introduced for variable amplitude loading. This approach is found to improve the KBM‐based life predictions. 相似文献