Infrastructure deployment under uncertainties and competition: The biofuel industry case

Technological paradigm shifts often come with a newly emerging industry that seeks a viable infrastructure deployment plan to compete against established competitors. Such phenomenon has been repeatedly seen in the field of transportation systems, such as those related to the booming bioenergy production, among others. We develop a game-theoretic modeling framework using a continuum approximation scheme to address the impacts of competition on the optimal infrastructure deployment. Furthermore, we extend the model to incorporate uncertainties in supply/demand and the risk of facility disruptions. Analytical properties of the optimal infrastructure system are obtained, based on which fast numerical solution algorithms are developed. Several hypothetical problem instances are used to illustrate the effectiveness of the proposed algorithms and to quantify the impacts of various system parameters. A large-scale biofuel industry case study for the U.S. Midwest is conducted to obtain additional managerial insights.     

Through-wall yield ductile burst pressure of high-grade steel tube and casing with and without corroded defect

Service environment of tube and casing in deep and ultra-deep well is getting more and more complicated, and the internal pressure applied to tube and casing is higher, so that the high-grade steel tube and casing (HGTC) made of ductile material is widely used. Obviously, the calculation of ductile burst pressure for HGTC is one of the key factors in design and important to safe and efficient development of unconventional oil and gas resources. Here, based on the failure principle of through-wall yield and unified yield criterion, the unified formula of through-wall yield ductile burst pressure (TYBP) for tube and casing under practical service condition which can be used to calculate TYBP of API HGTC and non-API HGTC accurately and reasonably by using true material parameters, has been deduced in this paper with due consideration of the effect of Bauschinger effect (BE), material hardening and intermediate principal stress (IPS) on the TYBP, by which the influence rules of BE, IPS and yield criterion on TYBP of tube and casing have been investigated.（The effect of lattice effect (BE), material hardening and intermediate principal stress (IPS) on TYBP is accurately and reasonably derived from non-API HGTC by using real material parameters. The value of BE, IPS and the TYBP yield criterion of pipe and casing are studied. Eight kinds of classic through-wall yield ductile burst formulas for tube and casing made of new material have been be derived from a series of yield criterion, by which TYBP model of HGTC with and without corrosion defect has been established based on weighted twin shear stress yield criterion. The calculation results of TYBP model presented by this paper are the closest to the full-scale burst experimental data than the other burst models, which can provide an important reference for burst pressure design and estimation of HGTC in deep and ultra-deep well.     

Towards a unified methodology for the simulation of rupture in collision and grounding of ships

The aim of the work is the definition of a procedure for the numerical simulation of the response of ship structures under accidental loading conditions, which suffer various different modes of failure, such as tension, bending, tearing and crushing and in particular to investigate the effect of material modeling, i.e. material curve and rupture criterion as well as mesh size and strain rate effect on the results. To this end, different material models and simulation techniques were used for the simulation of eighteen indentation tests conducted by different research groups. The simulations were performed using the explicit finite element code ABAQUS 6.10-2. The tests refer to the quasi-static and dynamic transverse and in-plane loading of various thin walled structures which represent parts of a ship structure. Three rupture criteria are incorporated into VUMAT subroutine, which interacts with the explicit finite element code and refers to an isotropic hardening material that follows the J₂ flow theory assuming plane stress conditions, in order to investigate the prediction and propagation of rupture. The focus is on investigating whether it is possible to define a unified methodology, which is appropriate for the simulation of all different tests. Consistency in the numerical results is observed with the use of an equivalent plastic strain criterion, in which formulation a cutoff value for triaxialities below −1/3 is included.     

汽车铝热压模的选材与试验研究

原３Ｃｒ２Ｗ８Ｖ材料制造的汽车铝热压模会产生型腔软塌、热磨损等失效形式，提出选用ＲＷ４０钢硬质合金加以制造，对ＲＷ４０合金进行工艺试验，指出锻压变形有利于提高其性能，并讨论了锻压前、后的处理工艺。同时对ＲＷ４０合金制汽车铝热压模复合强化处理工艺加以探讨。     

二灰砂土路面底基层施工质量控制

结合２０５国道博莱高速公路底基层的施工，介绍了工程中如何对二灰砂土底基层三项指标，即强度、压实度和平整度的质量进行控制。     

我国汽车材料发展的几点史实和车辆用材的某些考虑

本文回顾了我国汽车工业发展简史和用料总量。回顾了国际封锁禁运下,我国如何自力更生地开发适合我国资源条件的汽车合金钢系列和低合金高强度钢板系列,节约了镍铬;并论证大量生产的大件商品——汽车必须考虑节约稀缺资源。关于汽车构造基体金属的探讨,突出了现代铸铁的技术进步;对铝、镁、钛用于汽年的前景也作了思考。本文最后讨论非金属材料中的木材、竹材和塑料,提出金属与非金属材料的最佳组合将对今后的汽车作出贡献,孕育出一代代的新型汽车。     

浅谈高速公路材料质量控制

介绍了公路常用材料的检验项目、频率和主要质量控制项目。通过预防、采取措施,达到监控目的,有效地控制了原材料的质量。     

WB36管道焊接的工艺试验研究

由于具有较高的综合机械性能，WB36钢已逐渐成为新型电站给水系统管道用钢的首选材料。按照国家相关焊接工艺评定规范的具体要求，选择了一种较新型的焊接材料，按照工艺设计，对这种高强度的低合金管道用钢进行了一系列的试验和分析，在焊接接头的各项性能满足要求后，证实了用于实际生产的可行性。     

高动力、高压电力设备合理选型配置在隧道进口中的应用

结合太行山隧道进口工程施工,介绍高动力、高压电力设备的合理选型配置和注意事项。通过实践,达到了预期的技术目标和要求,既保证了隧道的安全、优质、高效施工,又节约了隧道施工成本。     

Dynamic response analysis of towed cable during deployment/retrieval

A numerical approach was developed to analyze the transient behavior of towed cable during ac- tively controlled deployment/retrieval (DR). The cable motion is described by the lumped parameter method, its corresponding boundary conditions are presented. In view of its varying length during DR, two auxiliary arguments are introduced to describe its continuous varying length and discrete number of nodes(equations), the length is determined by the pay out(or reel-in) rate, which is then used to determine the node number by a logic relation. For the discrete mathematical model of towed cable, an algorithm was developed to deal with the discrete governing equations. The simulation results indicate that the cable experiences more com- plex motions due to its varying length, and tension fluctuates seriously in the startup and ending stage of deployment/retrieval. The effect of towing ship's motion in waves on cable during deployment/retrieval is also considered via numerical simulation.