The basic approach of protecting people from being hurt or killed in an accident is to improve crashworthiness of vehicles. This paper starts with discussing theories and methods for vehicle passive safety design, which included experiential methods, analytic methods, multi-body dynamics methods, crash test methods and the finite element method. Emphasis will be paid to the basic FEM theories and algorithms of impact problems. Topics discussed include the governing equation, element discretization, hourglass control, time integration, material model, shell element algorithms and contact-impact algorithms. For more reliable simulation results, this paper then conducts study on how to accurately get material model parameters by combining the FEM method with experimental method, and develops relevant material test machine and parameter calculating software. Based on that, basic typical impact simulation and test validation study are conducted. On the basis of the above work, the paper studies the thin-shell structures'crashworthiness, which was affected by the following factors: spot-weld features, shell thickness, cross-section and pre-deformation. As to vehicle parts'crashworthiness, the paper conducts simulation study of designing energy-absorbing steering system and adaptive airbag system. A practical energy-absorbing steering wheel is designed as an example. In further depth research, the paper suggests several inverse quantificational methods for vehicle crashworthiness design based on the ideal crash characteristics. The above theories and methods are applied with good results through several practical vehicles' crashworthiness design and improvement.

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Disk within androecium, nectariferous, flattened, annular, cup-shaped, pulvinate, or sometimes columnar, bell-shaped, conic, or hourglass-shaped.

花盤 在雄蕊群內，分泌蜜汁日韩手机在线视频久操，扁平，環(huán)狀国产成人嫖妓视频下载网站在线观看，杯形日本免费三网站，枕狀，或者有時柱形欧美操逼电影，鈴形人人操人人看人人拍，圓錐形黄色网页在线欧美，或者沙漏形。

Later the sand ran out of the hourglass by the binnacle and he turned it and rang the ship's bell.

過了一會兒调教一区，他看到羅盤操作臺旁邊的沙漏計時器已經(jīng)漏光了砂子免费无码又爽又刺激A片涩涩。

Among the many remarkable final projects that have been proposed and presented at the end of the course have been a Renaissance hourglass blown in the MIT glass shop and set into a frame turned on our set shop lathe; a four harness loom built by a student who then wove cloth on it; a number of chain mail tunics and coifs; a wide variety of costume and furniture pieces and electrified period lighting fixtures.

在以往的課程中，學生們構想并于期末展示出了很多優(yōu)秀的作品啊使劲c我高清在线观看，比如一個文藝復興時期的沙漏超碰人妻久久，它是學生在麻省理工學院的玻璃工作坊吹制、并在我們布景工作坊的車床上成形的影音先锋熟女AV下载电影；一臺由學生制作的四綜紡織機欧美一级婬片日本高清视，制作者真正用它來織布；許多鎖子甲束腰外衣和頭巾久草高清巨乳；各式各樣的服飾国产精品毛片无码,啦啦啦、家俱和電氣化時代的照明設備。

The copper clepsydra was also called a water clock, hourglass, and sandglass.

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Meshing properties and application of major conical surface double envelope Hourglass worm gearing;2. In this paper, the regularities of undercutting and topping of major conical surface envelope hourglass worm is researched.

分析了大錐面包絡環(huán)面蝸桿的齒頂變尖和根切規(guī)律99久久国产精品无码免费，并通過和平面包絡環(huán)面蝸桿的比較，得出其在根切和齒頂變尖這兩個方面具有比平面包絡蝸桿更優(yōu)良的性能亚洲精品第一国产综合精品91，因而是一種在實際中可替代平面包絡男生带套套会不会弄出血、具有廣泛應用前景的新型包絡蝸桿傳動。

On the condition of "many-head" and "small drive ratio",the plane double enveloping hourglass worm can not settle the problem of undercutting and sharpening simultaneously.It has devoted to a new type hourglass worm_sphere double enveloping hourglass worm.

考慮到平面二次包絡環(huán)面蝸桿傳動在多頭小傳動比條件下根切與齒頂變尖的矛盾很難同時解決且嚙合性能較差毛片网址在哪里，介紹了一種新型環(huán)面蝸桿傳動——球面二次包絡環(huán)面蝸桿傳動女人被男人桶30分钟动态图。

On the basis of the research on the model of the planar enveloping hourglass meshing surface, the software is developed in which the design environment of enveloping hourglass worm pairs is parameterized.

在平面包絡環(huán)面嚙合型面的精確建模等研究的基礎上，進行了包絡傳動副嚙合副參數(shù)化設計環(huán)境的軟件開發(fā)美国a级大黄片。

Furthermore, the reconstituted model of planar enveloping hourglass meshing surface is established in the light of the research of 3D surface reconstituted algorithm, and 3D error of the real planar enveloping hourglass meshing surface is derived accordingly.

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Abrasive disk for accurately grinding TI worm,as well as grinding method similar to that for globoid worm or planer enveloping hourglass worm,is used to machine hourglass worm,making the TI worm match with the worm wheel which has the same tooth surface shape as that of abrasive disk,and thus forming a new-style worm gearing .

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