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G. Shi,Z. Liu,H.Y. Ban,Y. Zhang,Y.J. Shi,Y.Q. Wang 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.12 No.1
Local buckling can be ignored for hot-rolled ordinary strength steel equal angle compression members, because the width-to-thickness ratios of the leg don’t exceed the limit value. With the development of steel structures, Q420 high strength steel angles with the nominal yield strength of 420 MPa have begun to be widely used in China. Because of the high strength, the limit value of the width-to-thickness ratio becomes smaller than that of ordinary steel strength, which causes that the width-to-thickness ratios of some hot-rolled steel angle sections exceed the limit value. Consequently, local buckling must be considered for 420 MPa steel equal angles under axial compression. The existing research on the local buckling of high strength steel members under axial compression is briefly summarized, and it shows that there is lack of study on the local buckling of high strength steel equal angles under axial compression. Aiming at the local buckling of high strength steel angles, this paper conducts an axial compression experiment of 420MPa high strength steel equal angles, including 15 stub columns. The test results are compared with the corresponding design methods in ANSI/AISC 360-05 and Eurocode 3. Then a finite element model is developed to analyze the local buckling behavior of high strength steel equal angles under axial compression, and validated by the test results. Followingthe validation, a finite element parametric study is conducted to study the influences of a range of parameters, and the analysis results are compared with the design strengths by ANSI/AISC 360-05 and Eurocode 3.
Influence of residual stress on the adhesive behavior of detonation gun sprayed WC-Co coatings
Wang, T.G.,Liu, Y.,Wang, Q.,Gong, J.,Sun, C.,Kim, K.H. Elsevier 2012 Current Applied Physics Vol.12 No.suppl2
The residual stresses generated during D-Gun spraying process act as pre-existing stresses and seriously affect the various types of coating performance. To produce a reliable coating, it is necessary to know the influence of residual stress on the adhesive behavior of coating/substrate system. Based on the residual stress formula for thick coatings and accurate curvature measurements, the residual stresses of D-Gun sprayed WC-Co coatings were obtained. And a strong link was built between the residual stress and the adhesive strength of the coating, namely, the compressive stress in the coating could significantly improve the adhesion, whereas the tensile stress weakened the adhesion. The larger compressive residual stress is in the coating, the stronger adhesion between the coating and substrate.
Evaluating the effectiveness of ERS for vessel oil spills using fuzzy evidential reasoning
Wang, H.Y.,Ren, J.,Yang, J.Q.,Wang, J. Techno-Press 2015 Ocean systems engineering Vol.5 No.3
An emergency response system (ERS) for vessel oil spills is a complex and dynamic system comprising a number of subsystems and activities. Failures may occur during the emergency response operations, this has negative impacts on the effectiveness of the ERS. Of the classes of problems in analyzing failures, the lack of quantitative data is fundamental. In fact, most of the empirical data collected via questionnaire survey is subjective in nature and is inevitably associated with uncertainties caused by the human being's inability to provide complete judgement. In addition, incomplete information and/or vagueness of the meaning about the failures add difficulties in evaluating the effectiveness of the system. Therefore this paper proposes a framework to evaluate the ERS effectiveness by using the combination of fuzzy reasoning and evidential synthesis approaches. Based on analyzing the procedure of ERS for oil spills, the failures in the system could be identified, using Analytic Hierarchy Process(AHP)to determine the relative weight of identified failures. Fuzzy reasoning combined with evidential synthesis is applied to evaluate the effectiveness of ERS for oil spills under uncertainties last. The proposed method is capable of dealing with uncertainties in data including ignorance and vagueness which traditional methods cannot effectively handle. A case study is used to illustrate the application of the proposed method.
Wang, Y.Q.,Byun, J.H.,Kim, B.S.,Song, J.I.,Chou, T.W. Pergamon Press ; Elsevier Science Ltd 2012 Carbon Vol.50 No.8
Vapor grown carbon nanofibers (VGCNFs) were deposited on carbon fibers (CFs) using electrophoretic deposition (EPD). Composites of the resulting hybrid material (CF-VGCNF) in an epoxy matrix were fabricated by the vacuum-assisted resin transfer molding process. The electrical conductivities of the composites were significantly improved compared to those without the VGCNF reinforcement. The Taguchi method was used to optimize the EPD process conditions through the analysis of means and the analysis of variance for achieving a highly uniform deposition of carbon nanofibers. The parameters considered for optimization are: deposition time, applied voltage, concentration of VGCNF in a distilled water suspension, and the distance between anode (a carbon fabric) and cathode (a copper plate). An orthogonal array of L<SUB>9</SUB> (3<SUP>4</SUP>) was created in the statistical design of experiments. The through-thickness electrical conductivity of the composites produced using the optimum deposition conditions was more than 90 times that of carbon fiber/epoxy composites. When compared with the average electrical conductivity of the nine design experiments, the electrical conductivity of the CF-VGCNF/epoxy composite using a filler prepared under the optimum deposition conditions showed a 51% improvement.
On complex flutter and buckling analysis of a beam structure subjected to static follower force
Wang, Q. Techno-Press 2003 Structural Engineering and Mechanics, An Int'l Jou Vol.16 No.5
The flutter and buckling analysis of a beam structure subjected to a static follower force is completely studied in the paper. The beam is fixed in the transverse direction and constrained by a rotational spring at one end, and by a translational spring and a rotational spring at the other end. The co-existence of flutter and buckling in this beam due to the presence of the follower force is an interesting and important phenomenon. The results from this theoretical analysis will be useful for the stability design of structures in engineering applications, such as the potential of flutter control of aircrafts by smart materials. The transition-curve surface for differentiating the two distinct instability regions of the beam is first obtained with respect to the variations of the stiffness of the springs at the two ends. Second, the capacity of the follower force is derived for flutter and buckling of the beam as a function of the stiffness of the springs by observing the variation of the first two frequencies obtained from dynamic analysis of the beam. The research in the paper may be used as a benchmark for the flutter and buckling analysis of beams.
Wang, M.Q.,He, Y.D.,Lindemann, M.D.,Jiang, Z.G. Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.10
The study was conducted to evaluate the effects of trivalent chromium from different sources on growth, carcass composition, and serum parameters in finishing pigs. Ninety-six crossbred pigs with an initial average body weight of 65.57${\pm}$1.05 kg were blocked by body weight and randomly assigned to four treatments with three replicates. Pigs were offered one of four diets including a control diet or the control diet supplemented with 200 ${\mu}g/kg$ chromium from either chromium chloride ($CrCl_{3}$), chromium picolinate (CrPic) or chromium nanocomposite (CrNano) for 40 days. After completion of the feeding trial, eight pigs from each treatment were selected to collect blood samples, and slaughtered to measure carcass composition. The results showed that supplemental chromium had no significant effect on growth performance, while CrNano increased carcass lean proportion and loin Longissimus muscle area (p<0.05), and decreased carcass fat proportion and 10th rib backfat depth (p<0.05). CrPic supplementation also resulted in lower fat proportion and larger Longissimus muscle area (p<0.05). The addition of Cr from CrNano or CrPic decreased serum glucose (p<0.05) and increased concentrations of total protein and free fat acid in serum (p<0.05). Serum urea nitrogen, triglyceride and cholesterol were decreased (p<0.05), and serum high density lipoprotein and lipase activity were increased (p<0.05) with the supplementation of CrNano. Serum insulin was decreased (p<0.05) by supplemental Cr from CrNano or CrPic, and serum insulin-like growth factor I was increased significantly in the CrNano treated group. These results suggest that chromium nanocomposite has higher efficacy on carcass composition in pigs compared to the traditional chromium sources.