机械毕业设计英文外文翻译386浅谈液化石油气半挂车设计新趋势对危运车辆行驶安全性能的影响

附录

附录A外文文献资料

Design of a new trend of LPG semi-trailer transport of dangerous safety performance of

vehicles

The liquefied gas tanker domestic production structure for the bicycle more fixed, because the restrictions by the carrying capacity of the chassis, can only reach its load capacity 10t. As in recent years, the amount of liquefied petroleum gas storage and transportation, the rapid increase in demand, particularly in improving the quality of road transport, small tonnage tanker transport capacity becomes low, high transport costs, this market for car transport tanker tonnage of cycling requirements grow. This paper introduces the structure of liquefied petroleum gas tank trailer features and design, through the tank stress calculation, strength check, and the axle load on the vehicle, driving stability, traction and climbing ability of the calculation, and running on prototype tests conducted to prove that the trend of the vehicle structure design. Through in-depth investigation and analysis, to grasp new trends in the design of LPG semi-trailer, concrete analysis of market segments in which the product, liquefied petroleum gas tank semi-trailer on the overall market supply and demand trends in the industry and industry prospects to judge since the state has promulgated to implement " road vehicles outside the profile dimensions, axle load limits and quality "(GB1589-2004) standards, the interpretation of a semi-trailer to reduce the total mass of liquefied gas, and strive to maximize tank volume tank to raise the maximum filling of semi-trailer containing a single volume, to meet customer everything possible to reduce per ton / km of running costs for the design of the mentality and needs of the guiding ideology of the revolution.

First, the latest design features of LPG semi-trailer.

When the series of 25 tons of domestic LPG semi-trailer loaded with 46 tons more than the total mass of the country reduced to the maximum limit of 40 tons, the previous semi-trailer designed for maximum filling volume decreased from the 24.6 tons to 22.3 tons, significantly reduced transport capacity of a single set about 10%, which means a corresponding increase in the cost of transport enterprises by 10% or so.Semi-trailer manufacturing company in order to enhance their market competitiveness, focusing on how the standard of strict compliance with existing GB1589, based on the optimal design, reduce curb weight semi-trailer, tank for tank and racked their mind to maximize volume;

on liquefied petroleum gas trailer for the structural transformation, including:

1. Tank and the connection between car beam, integral bar from the previous V-bearing, use only part of the running gear to ensure the connection with the short V-bearing; then gradually converted to cancel the V-bearing, the use of travel agencies car beam and bearing with integrated anti-T-composite structure of saddle connections;

2. Tank with hemispherical head instead of elliptical head

3. Individual manufacturers to give up the tank with improved rigidity and prevent deformation of the X-shaped anti-tank punch plate, back in the past two-tier board structure arc erosion control;

4. Reduce the number of stiffening ring inside the tank or sewage outlets to give up;

5. Give up the position of assisting the buttress in the legs;

6. Working with an emergency shut-off valve and ball valve integrated structure;

7. Continue using the successful experience of the past, according to the tank to calculate the minimum wall thickness, the choice of filter plates for cylinder and so on.

Second, the new analysis of the safety of design ideas

In fact, the tank used by the manufacturer transformation initiative is set to meet the user's largest single semi-trailer reached 23.6 tons filling the ideal requirements. However, everything must be viewed in two, as the inflammable and explosive dangerous goods transport vehicles, LPG semi-trailer manufacturing quality, the key is to ensure that its design is reasonable, driving stability and security and reliability. The following semi-trailer used in the process of discovery, as a result of traffic accidents caused by product quality and defects, which should be attached great importance to the tank manufacturer, and in pressure vessel quality assurance system to control operation:

1. over the past three years, China's liquefied gas tanker car manufacturing has been using

a V-bearing + Deck + bolt connecting structure, and solve the tank and the vehicle chassis (or travel agencies) the connection between the way the problem fixed. To reduce the trailer's cur

b weight, the current domesti

c sales of the larger manufacturers have a few semi-trailer running gear design an

d us

e o

f tank car bearin

g beam and the integration of anti-T-composite structure wit

h saddle connections. Tank manufacturers only need to hang on the tank provided by the manufacturer of the running gear frame, through the assembly, calibration, welding, the tank and the connection between the vehicle running gear fixed on the basic process to complete. I am nearly similar according to the structure of LPG vehicles, semi-trailer tracking product quality, the following design and manufacturing production plant critical control point is overlooked by quality assurance system:

(1)According to the liquefied gas tanker manufacturing quality control requirements, in order to ensure vehicle stability, the industry would tank and the chassis (or travel agencies) the offset between the control center 4 mm range, horizontal line at both ends of the tank and the difference between the level of vehicle control beam of 3 mm within the reference index as an ideal quality. In fact, if the manufacturer of the tank by GB150 roundness is less than 1%, and the tank line is no more than 1 ‰ of the minimum molding control requirements, and the coupling pin in the nozzle and the traction pin seat positioning completed After assuming the two-bar frame anti-T-bearing composite structure and size of saddle is very accurate, when the tank and running gear assembly, the tank itself, the manufacturing quality of the error, the offset will inevitably lead to the tank center and sales offset excessive traction.

(2)long used in the past, V-bearing beams connecting the tank and the vehicle structure, uniform continuity of the advantages of mechanical load. The use of vehicles bearing beam and the integration of anti-T-composition and structure of the saddle connection, we must focus through the addition of multiple internal and external vertical stiffener plates, bearing a reasonable decomposition and distribution

Force loading problem; if a simple distributed 5 6 ribs plate, semi-trailer must constitute a threat to driving safety and stability. Car bearing beam and the integration of anti-T-composite structure with saddle connections are rigid structures; how to eliminate the gravity load tankers in the process of turning the tangential tensile stress produced by the composition of the local tensile stress concentration, avoid these pads board pulled crack occurrence of adverse working conditions manufacturers must pay attention to the technical issues.

(3)observation of a used vehicle in which the integration of beam and bearing anti-T-composite structure with the saddle running gear, the occurrence of semi-trailer rollover accident, found that the right of the three-axis and the end of the spring steel beam bearing fillet weld connection between almost cracking, the basic failure of the running gear. The key reason is the selection of thin components, welding angle factor due to poor weld quality; is associated with decreased weight of the walking mechanism, this should cause the manufacturer's attention.

2, the tank instead of using spherical head oval head has become a tanker car manufacturers in the design and manufacture of semi-trailer, another characteristic of LPG. In fact LPG Tank Car manufacturing plant will be semi-trailer tank diameter of 2.45 meters, set the length of 12.7 meters, has the current profile of GB1589 standards on vehicles used

to limit the size requirements. From the point of view of optimal design, the use of spherical head instead of elliptical head, really can set the maximum filling volume of a single semi-trailer upgrade to 23.5 tons; and that the structure is also very popular in foreign countries. According to recent years in Guangzhou since the range of 6 22 ~ 25 tons of LPG semi-trailer accident site survey results showed:

(1) As the heavy semi-trailer high center of gravity, gravity inertia; in the normal speed, flat road surface state rollover occurs, because the dodge oncoming traffic, caused by personnel or debris; and turn into the freeway ramp road rollover occurs, because the speed too fast (greater than 30 km / h) due.

(2) flat surface state, the tank first impact with the ground on both sides of the site is mainly horizontal centerline tank that is 90 °or 270 °around the head and cylinder connection weld area; turn road condition, can body of the first ramp on the fence with concrete buildings and the site of impact is mainly horizontal in the tank line that is 45 ° ~ 90 ° or 270 ° ~ 315 ° around the front and rear head and cylinder connection weld area. (3) the impact force and the inertia that hit parts of the tank, without exception, all have a diameter of about 400 mm, a depth of about 60 mm or so irregular, radial V-pot type or serious injury of concave defects.

(4) and the spherical head tank, turn the semi-trailer overturned in the accident, the damage produced by the same defect feature; and in 90 °or 270 °or so before the spherical head and cylinder connecting ring welding also form a joint region about 800 mm or so of flat fall flat damage defects.

(5) whether the material is used 16MnR, 16 (or 14) mm thickness of elliptical heads or 10 mm thickness of the spherical head structure, the concave semi-trailer accident cases experienced no damage by sharp metal parts object impact test, it did not lead to cracking and leaking tank. In comparison, from the point of view of impact resistance, both the choice of head structure, has not yet significantly better or worse.

However, once the face of such semi-trailer rollover accidents the majority of the tank due to surface scratches and the concave defect repair costs too much, basically can not escape the fate of abandoned vehicle.

3. the auxiliary trailer buttress is an additional safety barrier. In the semi-trailer design process, most designers believe that more than 25 tons with two legs can meet in the semi-trailer or heavy load conditions, with the tractor connection, or decoupling, static display and other conditions when the total Quality carrying 40 tons of gravity and impact requirements. As a user, the operation based on two semi-trailer real trailer accident cases

and to improve the security of the grounds of sex drive, but requires the designer to consider assisting the buttress between the two legs.

(1) Case I: hanging off the overloaded condition, the ground is not flat, two legs Shouli Bu uniform, within the gear leg sudden failure, the occurrence of the phenomenon sweeping gear, tanks and gravity will be 8 groups leg All connection bolts between the frame tangential cut; eventually led to the first half of semi-trailer collapsed.

(2) Case II: After the tractor trailer mounted liquefied petroleum gas, due to the pin on the tractor tray is not completely reset, the process of moving semi-trailer from the tractor suddenly pulling off the tray, resulting in the first half of semi-trailer collapsed.

(3) Fortunately, the two semi-trailer accidents are supporting buttress help, only to avoid the former head of the tank due to the impact with the ground directly damaged by the occurrence of fatal accidents.

4.the case of the above-mentioned incidents, one of which is a semi-trailer turn in the highway bridge approach due to excessive speed, concrete barrier and light pole to the left side of the tank barriers and sweeping off the valve box, directly under the bridge and turn over; Box integrated structure within the gas and liquid handling the emergency shut-off valve and liquid valve port for which parts of the flange connection flange cut, gas port flange bolts part of the fracture, and the assembly flange bending, two mouth leak conductance and fire; the field environment and cracking, leaking part structure is complex, and ultimately fighting for an ideal sealing measures can be taken, and taken to the fire water tank temperature control, so that liquefied petroleum gas tank completely burned up.

Third, some suggestions

1. in order to improve the process of moving liquefied trailer security and stability, the production plant in the tank manufacturing quality assurance control points need to strengthen the supervision of the following tests:

a, the current shape with spinning head of the factory fixture quality and the ability of manufacturers to design and manufacture the maximum and minimum diameter of the tank should be controlled within 0.5% deviation range, and level layout as the largest diameter, To lay the foundation for optimizing the quality of vehicle assembly;

b, formed in the cylinder section, should be based on the distribution of longitudinal weld requirements, try to avoid the maximum or minimum diameter tube section located in the bearing plate surrounding parts of the range, so as not to leave the tank and the tank when the center bearing assembly flat shift too much security risk;

c, in order to ensure the straightness of the tank, and pulling off the tray, gas liquid nozzle flange and other location marking, and welding, care must be neutral and traction pin tray on the center plane and the vertical tank; take effective measures to prevent the welding deformation process; Also in the design, the two groups should be properly opened the distance between the gas and liquid phase flange to avoid welding deformation.

d, must be avoided head, cylinder group between sessions to strengthen the ring and erosion control board assembly process at the phenomenon of forced assembly; equitable distribution of stiffening ring, welding deformation of the tank to minimize the roundness and straightness of.

2.the walking beam and for selection of cars bearing the anti-T-integrated composite structure with saddle connections of the manufacturers, designers should be fully considered bearing in the rear tank, and between the bearing and the tank car beam and suspension systems and other connections between the parts of the various stress conditions, to avoid the above mentioned connection structure or connection weld and other defects.

3, a single leg selection should be not less than 50 tons. Will complement the V-set in the two legs between the buttress, and its high degree of control from the ground at about 450 ~ 490 mm.

4, semi-trailer running gear manufacturers in the assembly, you must also ensure that the balance of triaxial; ensure that each axis of each brake hub and bearings with the symmetry of the center line of the running gear and neutral.

5, tankers and rescue safety valve leakage is still the most delicate issues. According to the characteristics of tankers built-in safety valve, without violating the mobile pressure vessels under the premise of the relevant regulations, to consider the safety valve with built-in, no extended segment, concealed protection designed to reduce security risks tanker accident. 6, the tank is designed emergency outfall connecting port, built-in check valve and the suction ring gimbal the nozzle device; in the event of a rollover accident, can be quickly connected to an external, removable tank of liquefied petroleum gas, reduce on-site rescue difficulty and risk.

Summarized three decades dealing with liquefied gas tanker car experience, I fully understand the current national standard GB1589-made restrictions on the trailer. Currently there is not actually capable of producing the quality of the saddle contains ≥ 16 tonnes gross vehicle weight of ≥ 40 tons tow tractor manufacturers and alternative models is small; and are willing to invest capital, imported high-powered tractors are very few

companies . LPG semi-trailer in order to ensure driving safety performance, both manufacturers and users should be from the design, manufacture and use of the three links off to a good product quality and safety, particularly in ensuring the safety of dangerous driving performance transport vehicles make great efforts; common made a good-shaped, high-quality semi-trailer the safe use of liquefied petroleum gas environment.

附录B外文资料中文翻译

浅谈液化石油气半挂车设计新趋势对危运车辆行驶安全性能的影响

国内生产制造的液化气罐车结构多为单车固定式，因其受底盘承载能力的限制，其装载量仅能达到10t。随着近年来液化石油气储运量、需求量的迅猛增加，特别是运输道路质量的提高，小吨位的罐车就显得运输能力低，运输成本高，为此市场上对汽车罐车的单车运输吨位要求越来越大。文章介绍了液化石油气罐半挂车的结构特点及设计方案，通过对罐体的应力计算、强度校核和对整车的轴荷、行驶稳定性、牵引性能、爬坡能力等的计算，及对样车进行的运行试验，证明该车结构设计合理的趋势。通过深入调查分析，把握液化石油气半挂车设计新趋势，具体分析该产品所在的细分市场，对液化石油气罐半挂车行业总体市场的供求趋势及行业前景做出判断自从国家颁布、实施《道路车辆外廓尺寸、轴荷及质量限值》（GB1589—2004）标准后，演绎了一场以降低液化气体半挂车总质量、争取罐车罐体容积最大化、提高半挂车单载最大充装量、满足客户千方百计降低每吨/公里运行成本的心态和需求为设计指导思想的

革命。

一、最新设计的液化石油气半挂车特点

当国内25吨系列液化石油气半挂车满载总质量由46吨多降低到国家限制的最大40吨时、以往设计的半挂车最大充装量由24.6吨降低到22.3吨，单载运输能力明显减少10%左右，意味运输企业成本相应提高了10%左右。半挂车制造企业为了提升自身的市场竞争能力，围绕如何在严格遵守现行GB1589标准的基础上，优化设计，降低半挂车整备质量、争取罐车罐体容积最大化而费尽了心思；对液化石油气半挂车进行了结构性技术改造，主要包括：

1．罐体与车梁之间的连接，由以往整体式长条V型支座、改用只保证与行走机构部分连接的短V型支座；再逐步转化为取消V型支座、采用行走机构的车梁与支座一体化的反T型与鞍座组合结构的连接方式；

2．罐体采用半球形封头代替椭圆封头

3．个别厂家放弃了具有提高罐体刚性、防止罐体变形的X形防冲板结构，回复以往的双层弧形防冲板结构；

4．减少罐体内部加强圈数量或放弃设置排污口；

5．放弃在支腿位置设置辅助支墩；

6．采用紧急切断阀与装卸球阀一体化结构；

7．继续延用以往成功经验，根据罐体计算最小壁厚、选用筛选板作筒体等。

二、新设计思路的安全性分析

事实上，上述罐车制造厂家所采用的技术改造举措，是可以满足用户半挂车单载最大充装量达到23.6吨理想要求。但任何事物都必须一分为二看待，作为易燃易爆危险物品的运输车辆，液化石油气半挂车制造质量的关键是必须保证其设计的合理性、行驶的稳定性和安全可靠性。以下几个在半挂车使用过程发现的、以及因交通事故而导致的产品质量和缺陷问题，应引起各罐车制造厂家高度重视，并在压力容器产品质量保证体系运行过程加以控制：

1、过去三十多年，中国液化气体汽车罐车的制造一直采用V型支座+连接卡座+高强度螺栓组合结构、解决罐体与车辆底盘（或行走机构）之间的连接固定方式问题。为了降低半挂车的整备质量，目前国内销量较大的几家半挂车制造企业相继设计和采用行走机构的车梁与罐体支座一体化的反T型与鞍座组合结构的连接方式。罐车厂家只需要将罐体吊上制造商所提供的行走机构车架上，通过组装、校正、焊接后，罐体与车辆行走机构之间的连接固定工序就基本完成。根据本人对近十辆同类结构的液化石油气半挂车的产品质量跟踪，以下几个设计和制造关键控制点被生产厂质量保证体系所忽

视：

（1）根据液化气体罐车制造质量控制要求，为了保证车辆行驶稳定性，行业内将罐体与底盘（或行走机构）之间的中心偏移量控制在4毫米范围内、罐体水平线两端与车梁水平高低差控制在3毫米范围内作为理想的质量参考指标。事实上，如果制造厂家对罐体只是按GB150的圆度不大于1％和罐体直线度不大于1‰的最低成型控制要求时，在管口和牵引销及其牵引销座定位完成后，假定车架上的双条形反T型与鞍座组合结构支座尺寸十分准确，当罐体与行走机构组装时，由于罐体本身的制造质量误差，必然导致罐体中心偏移量和牵引销偏移量超标。

（2）以往所采用的长条V型支座的罐体与车梁连接结构，具有连续性均布受力载荷的优点。而采用车梁与支座一体化的反T型组合与鞍座结构的连接方式，必须注重通过增设多组内、外立式加强筋板、合理分解和分布支座的

受力载荷问题；如果简单地分布5~6条加强筋板，必然构成对半挂车行驶安全和稳定性威胁。车梁与支座一体化的反T型与鞍座组合结构的连接方式属于刚性连接结构；如何消除罐车在转弯过程重力载荷产生的切向拉应力所构成的局部拉应力过度集中，避免上述垫板被拉裂的恶劣工况发生是厂家必须关注的技术课题。

（3）观察分析其中一辆采用车梁与支座一体化的反T型与鞍座组合结构的行走机构的、发生翻车事故半挂车，发现其右边三组轴弹簧钢板支座与底梁之间的连接角焊缝几乎完全开裂、整个行走机构基本失效。究其原因主要是构件选材单薄、焊接角焊缝质量差等因素所致；是否与降低行走机构重量有关，这方面应引起生产厂家的高度重视。

2、罐体采用球形封头代替椭圆封头已经成为汽车罐车制造企业在设计和制造液化石油气半挂车的另一个特点。事实上汽车罐车制造厂将液化石油气半挂车罐体直径定为2.45米、长度定为12.7米，已经将现行GB1589标准有关车辆外廓尺寸的要求利用到极限。从优化设计的角度分析，采用球形封头代替椭圆封头，的确可以将半挂车单载最大充装量提升到23.5吨左右；而且该结构在国外亦十分普遍。根据最近几年发生在广州范围内的6起22~25吨液化石油气半挂车交通事故现场勘察的结果显示：

（1）由于重载半挂车重心高，重力惯性大；在正常车速、平直路面状态下发生翻车事故，皆因闪避迎面而来的车辆、人员或杂物所造成；而进入高速公路匝道转弯路面发生的翻车事故、皆因车速过快（大于30公里/小时）所致。

（2）平直路面状态下、罐体首先与地面撞击的部位主要是罐体两侧水平分中线即90°或270°左右的封头与筒体连接环焊缝区域；转弯路面状态、罐体首先与匝道上防护栏和混凝土建筑物撞击的部位主要是罐体水平分中线上即45°～90°或270°～315°左右的前、后封头与筒体连接环焊缝区域。

（3）冲击力和惯性使罐体撞击部位无一例外、均产生直径约400毫米、深度约60毫米左右的不规则、锅型或径向V型内凹的严重损伤缺陷。

（4）而采用球形封头罐体的、发生在弯道的半挂车翻车事故，其产生的损伤缺陷特征基本相同；且在90°或270°左右的前球形封头与筒体连接环焊缝区域还形成一个约800毫米左右的平板式扁塌损伤缺陷。

（5）无论是采用材质为16MnR、16（或14）毫米板厚的椭圆封头或10毫米板厚的球形封头结构，由于经历的事故案例半挂车内凹损伤部位均未受到尖锐性金属物撞击的考验，故未导致罐体开裂和泄漏。比较之下、从抵御冲击力的角度分析，两种封头结构的选择，目前还未有明显的优劣之分。

不过，该类半挂车一旦遭遇翻车事故，大多数的事故罐体由于表面刮伤和内凹缺陷修复费用太大，基本是逃脱不了整车报废的命运。

3、辅助支墩是半挂车的附加安全屏障。在半挂车设计过程，大多数设计者认为采用两个25吨以上的支腿完全可以满足半挂车在空载或重载条件下，与牵引车连接或脱钩、静止摆放时等工况下总质量为40吨的承载重力和冲击力要求。作为用户，则基于以下两个半挂车操作过程真实事故案例以及提高半挂车的安全行驶性等理由，而要求设计者考虑在两支腿之间设置辅助支墩。

（1）案例一：在重载脱挂工况下，由于地面不平整，两支腿受力不均匀、支腿内齿轮组突然失效、发生扫齿现象，罐体重力将8组支腿与车架之间的连接螺栓全部切向剪断；最终导致半挂车前半部分突然坍塌。

（2）案例二：牵引车挂上液化石油气半挂车后，因牵引车托盘上的保险销未完全复位，半挂车行驶过程突然牵引销脱离牵引车托盘，导致半挂车前半部分突然坍塌。

（3）所幸的是两起发生事故的半挂车都有的辅助支墩帮忙，才避免了罐体因前封头直接与地面撞击而受损的恶性事故的发生。

4、上述提及事故案例中，其中一起是半挂车在高速公路引桥转弯时因车速过快，混凝土护栏和灯杆将罐体护栏和左侧阀门箱扫脱、直接翻落桥底；箱内一体化结构的气液相紧急切断阀与装卸球阀因其中液相口在凸缘连接法兰部位剪断、气相口凸缘连接螺栓部分断裂、法兰与组合件弯曲、两管口泄漏导并起火；由于现场环境和开裂、泄漏部位结构复杂，最终因无法采取理想灭火堵漏措施、而采取罐体消防水降温控制方式、让罐内液化石油气完全烧光为止。

三、几点建议

1、为了提高液化气体半挂车行驶过程的安全与稳定性，各生产厂在罐体制造质量保证方面必须加强以下几个控制点的监督检验：

a、以目前采用旋压封头的成型质量和各制造厂工装夹具的能力，设计和制造时厂家应将罐体最大与最小直径差控制在0.5%范围内，且尽量水平布置最大直径，为优化整车组装质量打下基础；

b、在筒节成型时，应根据纵焊缝的分布要求，尽量避免筒节最大或最小直径部位分布在支座垫板周边范围内，以免留下罐体与支座组装时的罐体中心扁移过大的安全隐患；

c、为了保证罐体的直线度，对牵引销托盘、气液相管口凸缘等定位划线以及焊接时，必须注意牵引销的对中性和托盘平面与罐体中心的垂直度；采取有效的工艺措施防止焊接变形；另外在设计时，应适当拉开两组气液相凸缘之间的距离，避免焊接变形。

d、必须避免封头、筒节之间组对、加强圈及防冲板组装等过程出现强行组装现象；合理分布加强圈、最大限度降低焊接变形对罐体圆度和直线度的影响。

2、对行走机构选择车梁与支座一体化的反T型与鞍座组合结构的连接方式的厂家，设计者应充分考虑发生在罐体支座尾部、支座与罐体之间和车梁与悬挂系统之间等连接部位的各种应力工况，避免出现上述所提及的连接结构或连接焊缝等质量缺陷。

3、单个支腿选择应不少于50吨。将辅助V型支墩设置在两支腿之间，其离地面高度控制在约450到490毫米左右。

4、制造厂家在半挂车行走机构组装时，必须同时保证三轴的平衡度；保证每轴每组刹车毂、支座等与行走机构中心线的对称性和对中性。

5、罐车安全阀泄漏事故仍然是抢险最辣手的问题。根据罐车内装式安全阀的特点，在不违反移动式压力容器有关法规规定的前提下，考虑将安全阀采用内置、无外伸段、隐蔽式保护设计，以降低罐车事故安全风险。

6、将罐车排污口设计成紧急接驳口，内置单向阀和环形万向节吸液管口装置；一旦发生翻车事故，可以通过外部快速接驳、卸除罐内液化石油气，降低现场抢险难度和风险。

总结三十年与液化气体汽车罐车打交道的经验，我十分理解国家现行GB1589标准对半挂车制造的限制。目前国内有能力生产鞍载质量≥16吨、车辆总拖重量≥40吨的牵引车的厂家和可选择的型号不多；而愿意投入资金、采用进口大马力牵引车的企业亦极少。为了保证液化石油气半挂车的行驶安全性能，无论制造厂家和用户都应从设计、制造和使用三个环节上把好产品质量安全关，特别在保证危运车辆安全行驶性能方面狠下功夫；共同形造良好、优质的液化石油气半挂车的安全使用环境。

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毕业设计外文翻译

毕业设计（论文） 外文翻译 题目西安市水源工程中的 水电站设计 专业水利水电工程 班级 学生 指导教师 2016年

研究钢弧形闸门的动态稳定性 牛志国 河海大学水利水电工程学院，中国南京，邮编210098 nzg_197901@https://www.docsj.com/doc/5f2163199.html,，niuzhiguo@https://www.docsj.com/doc/5f2163199.html, 李同春 河海大学水利水电工程学院，中国南京，邮编210098 ltchhu@https://www.docsj.com/doc/5f2163199.html, 摘要 由于钢弧形闸门的结构特征和弹力，调查对参数共振的弧形闸门的臂一直是研究领域的热点话题弧形弧形闸门的动力稳定性。在这个论文中，简化空间框架作为分析模型，根据弹性体薄壁结构的扰动方程和梁单元模型和薄壁结构的梁单元模型，动态不稳定区域的弧形闸门可以通过有限元的方法，应用有限元的方法计算动态不稳定性的主要区域的弧形弧形闸门工作。此外，结合物理和数值模型，对识别新方法的参数共振钢弧形闸门提出了调查，本文不仅是重要的改进弧形闸门的参数振动的计算方法，但也为进一步研究弧形弧形闸门结构的动态稳定性打下了坚实的基础。 简介 低举升力，没有门槽，好流型，和操作方便等优点，使钢弧形闸门已经广泛应用于水工建筑物。弧形闸门的结构特点是液压完全作用于弧形闸门，通过门叶和主大梁，所以弧形闸门臂是主要的组件确保弧形闸门安全操作。如果周期性轴向载荷作用于手臂，手臂的不稳定是在一定条件下可能发生。调查指出:在弧形闸门的20次事故中，除了极特殊的破坏情况下，弧形闸门的破坏的原因是弧形闸门臂的不稳定;此外，明显的动态作用下发生破坏。例如:张山闸，位于中国的江苏省，包括36个弧形闸门。当一个弧形闸门打开放水时，门被破坏了，而其他弧形闸门则关闭，受到静态静水压力仍然是一样的，很明显，一个动态的加载是造成的弧形闸门破坏一个主要因素。因此弧形闸门臂的动态不稳定是造成弧形闸门(特别是低水头的弧形闸门)破坏的主要原是毫无疑问。

本科毕业设计外文翻译

Section 3 Design philosophy, design method and earth pressures 3.1 Design philosophy 3.1.1 General The design of earth retaining structures requires consideration of the interaction between the ground and the structure. It requires the performance of two sets of calculations: 1）a set of equilibrium calculations to determine the overall proportions and the geometry of the structure necessary to achieve equilibrium under the relevant earth pressures and forces; 2）structural design calculations to determine the size and properties of thestructural sections necessary to resist the bending moments and shear forces determined from the equilibrium calculations. Both sets of calculations are carried out for specific design situations (see 3.2.2) in accordance with the principles of limit state design. The selected design situations should be sufficiently Severe and varied so as to encompass all reasonable conditions which can be foreseen during the period of construction and the life of the retaining wall. 3.1.2 Limit state design This code of practice adopts the philosophy of limit state design. This philosophy does not impose upon the designer any special requirements as to the manner in which the safety and stability of the retaining wall may be achieved, whether by overall factors of safety, or partial factors of safety, or by other measures. Limit states (see 1.3.13) are classified into: a) ultimate limit states (see 3.1.3); b) serviceability limit states (see 3.1.4). Typical ultimate limit states are depicted in figure 3. Rupture states which are reached before collapse occurs are, for simplicity, also classified and