Relevant bibliographies by topics / Bioproducts; Structural change; Models

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Bioproducts; Structural change; Models'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Bioproducts; Structural change; Models.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Bioproducts; Structural change; Models"

1

Perron, Pierre, and Zhongjun Qu. "Estimating restricted structural change models." Journal of Econometrics 134, no. 2 (October 2006): 373–99. http://dx.doi.org/10.1016/j.jeconom.2005.06.030.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Chong, Terence Tai-Leung. "STRUCTURAL CHANGE IN AR(1) MODELS." Econometric Theory 17, no. 1 (February 2001): 87–155. http://dx.doi.org/10.1017/s0266466601171045.

Full text
Abstract:
This paper investigates the consistency of the least squares estimators and derives their limiting distributions in an AR(1) model with a single structural break of unknown timing. Let β1 and β2 be the preshift and postshift AR parameter, respectively. Three cases are considered: (i) |β1| < 1 and |β2| < 1; (ii) |β1| < 1 and β2 = 1; and (iii) β1 = 1 and |β2| < 1. Cases (ii) and (iii) are of particular interest but are rarely discussed in the literature. Surprising results are that, in both cases, regardless of the location of the change-point estimate, the unit root can always be consistently estimated and the residual sum of squares divided by the sample size converges to a discontinuous function of the change point. In case (iii), [circumflex over beta]2 does not converge to β2 whenever the change-point estimate is lower than the true change point. Further, the limiting distribution of the break-point estimator for shrinking break is asymmetric for case (ii), whereas those for cases (i) and (iii) are symmetric. The appropriate shrinking rate is found to be different in all cases.
APA, Harvard, Vancouver, ISO, and other styles
3

RAYKOV, TENKO. "On structural models for analyzing change." Scandinavian Journal of Psychology 33, no. 3 (September 1992): 247–65. http://dx.doi.org/10.1111/j.1467-9450.1992.tb00914.x.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Kramer, Walter, Werner Ploberger, and Raimund Alt. "Testing for Structural Change in Dynamic Models." Econometrica 56, no. 6 (November 1988): 1355. http://dx.doi.org/10.2307/1913102.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Su, Liangjun, and Halbert White. "TESTING STRUCTURAL CHANGE IN PARTIALLY LINEAR MODELS." Econometric Theory 26, no. 6 (March 22, 2010): 1761–806. http://dx.doi.org/10.1017/s0266466609990788.

Full text
Abstract:
We consider two tests of structural change for partially linear time-series models. The first tests for structural change in the parametric component, based on the cumulative sums of gradients from a single semiparametric regression. The second tests for structural change in the parametric and nonparametric components simultaneously, based on the cumulative sums of weighted residuals from the same semiparametric regression. We derive the limiting distributions of both tests under the null hypothesis of no structural change and for sequences of local alternatives. We show that the tests are generally not asymptotically pivotal under the null but may be free of nuisance parameters asymptotically under further asymptotic stationarity conditions. Our tests thus complement the conventional instability tests for parametric models. To improve the finite-sample performance of our tests, we also propose a wild bootstrap version of our tests and justify its validity. Finally, we conduct a small set of Monte Carlo simulations to investigate the finite-sample properties of the tests.
APA, Harvard, Vancouver, ISO, and other styles
6

Pang, Tianxiao, Terence Tai-Leung Chong, Danna Zhang, and Yanling Liang. "STRUCTURAL CHANGE IN NONSTATIONARY AR(1) MODELS." Econometric Theory 34, no. 5 (July 24, 2017): 985–1017. http://dx.doi.org/10.1017/s0266466617000317.

Full text
Abstract:
This article revisits the asymptotic inference for nonstationary AR(1) models of Phillips and Magdalinos (2007a) by incorporating a structural change in the AR parameter at an unknown time k0. Consider the model ${y_t} = {\beta _1}{y_{t - 1}}I\{ t \le {k_0}\} + {\beta _2}{y_{t - 1}}I\{ t > {k_0}\} + {\varepsilon _t},t = 1,2, \ldots ,T$, where I{·} denotes the indicator function, one of ${\beta _1}$ and ${\beta _2}$ depends on the sample size T, and the other is equal to one. We examine four cases: Case (I): ${\beta _1} = {\beta _{1T}} = 1 - c/{k_T}$, ${\beta _2} = 1$; (II): ${\beta _1} = 1$, ${\beta _2} = {\beta _{2T}} = 1 - c/{k_T}$; (III): ${\beta _1} = 1$, ${\beta _2} = {\beta _{2T}} = 1 + c/{k_T}$; and case (IV): ${\beta _1} = {\beta _{1T}} = 1 + c/{k_T}$, ${\beta _2} = 1$, where c is a fixed positive constant, and kT is a sequence of positive constants increasing to ∞ such that kT = o(T). We derive the limiting distributions of the t-ratios of ${\beta _1}$ and ${\beta _2}$ and the least squares estimator of the change point for the cases above under some mild conditions. Monte Carlo simulations are conducted to examine the finite-sample properties of the estimators. Our theoretical findings are supported by the Monte Carlo simulations.
APA, Harvard, Vancouver, ISO, and other styles
7

Vaninsky, Alexander. "Structural change optimization in input-output models." Journal of Interdisciplinary Mathematics 12, no. 6 (December 2009): 839–61. http://dx.doi.org/10.1080/09720502.2009.10700668.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Hansen, Bruce E. "Testing for structural change in conditional models." Journal of Econometrics 97, no. 1 (July 2000): 93–115. http://dx.doi.org/10.1016/s0304-4076(99)00068-8.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Wang, Shaoping, Guowei Cui, and Kunpeng Li. "Factor-augmented regression models with structural change." Economics Letters 130 (May 2015): 124–27. http://dx.doi.org/10.1016/j.econlet.2015.03.020.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Phillips, Peter C. B., Degui Li, and Jiti Gao. "Estimating smooth structural change in cointegration models." Journal of Econometrics 196, no. 1 (January 2017): 180–95. http://dx.doi.org/10.1016/j.jeconom.2016.09.013.

Full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Bioproducts; Structural change; Models"

1

Chen, Ya-Huei. "A study of freeze denaturation of proteins." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365813.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Westin, Lars. "Vintage models of spatial structural change." Doctoral thesis, Umeå universitet, Institutionen för nationalekonomi, 1990. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-73665.

Full text
Abstract:
In the study a class of multisector network models, suitable for simulation of the interaction between production, demand, trade, and infrastructure, is presented. A characteristic feature of the class is a vintage model of the production system. Hence, the rigidities in existing capacities and the temporary monopolies obtainable from investments in new capacity at favourable locations are emphasized.As special cases, the class contains models in the modelling traditions of "interregional computable general equilibriunT, Hspatial price equilibrium**, "interregional input-output" and transportation networks.On the demand side, a multihousehold spatial linear expenditure system is introduced. This allows for an endogenous representation of income effects of skill-differentiated labour.The models are represented by a set of complementarity problems. This facilitates a comparison of model properties and the choice of an appropriate solution algorithm.The study is mainly devoted to single period models. Such equilibrium models are interpreted as adiabatic approximations of processes in continuous time. A separation by the time scale of the processes and an application of the slaving principle should thus govern the choice of endogenous variables in the equilibrium formulation.
digitalisering@umu
APA, Harvard, Vancouver, ISO, and other styles
3

Zeileis, Achim, Friedrich Leisch, Christian Kleiber, and Kurt Hornik. "Monitoring structural change in dynamic econometric models." SFB Adaptive Information Systems and Modelling in Economics and Management Science, WU Vienna University of Economics and Business, 2002. http://epub.wu.ac.at/1296/1/document.pdf.

Full text
Abstract:
The classical approach to testing for structural change employs retrospective tests using a historical data set of a given length. Here we consider a wide array of fluctuation-type tests in a monitoring situation - given a history period for which a regression relationship is known to be stable, we test whether incoming data are consistent with the previously established relationship. Procedures based on estimates of the regression coefficients are extended in three directions: we introduce (a) procedures based on OLS residuals, (b) rescaled statistics and (c) alternative asymptotic boundaries. Compared to the existing tests our extensions offer better power against certain alternatives, improved size in finite samples for dynamic models and ease of computation respectively. We apply our methods to two data sets, German M1 money demand and U.S. labor productivity.
Series: Report Series SFB "Adaptive Information Systems and Modelling in Economics and Management Science"
APA, Harvard, Vancouver, ISO, and other styles
4

Zeileis, Achim, and Christian Kleiber. "Validating multiple structural change models. A case study." Institut für Statistik und Mathematik, WU Vienna University of Economics and Business, 2004. http://epub.wu.ac.at/584/1/document.pdf.

Full text
Abstract:
In a recent article, Bai and Perron (2003, Journal of Applied Econometrics) present a comprehensive discussion of computational aspects of multiple structural change models along with several empirical examples. Here, we report on the results of a replication study using the R statistical software package. We are able to verify most of their findings; however, some confidence intervals associated with breakpoints cannot be reproduced. These confidence intervals require computation of the quantiles of a nonstandard distribution, the distribution of the argmax functional of a certain stochastic process. Interestingly, the difficulties appear to be due to numerical problems in GAUSS, the software package used by Bai and Perron.
Series: Research Report Series / Department of Statistics and Mathematics
APA, Harvard, Vancouver, ISO, and other styles
5

Barth, Volker. "Integrated assessment of climate change using structural dynamic models." Hamburg : Max-Planck-Inst. für Meteorologie, 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968535933.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Zeileis, Achim, and Christian Kleiber. "Validating multiple structural change models. An extended case study." Institut für Statistik und Mathematik, WU Vienna University of Economics and Business, 2005. http://epub.wu.ac.at/280/1/document.pdf.

Full text
Abstract:
In a recent article, Bai and Perron (2003, Journal of Applied Econometrics) present a comprehensive discussion of computational aspects of multiple structural change models along with several empirical examples. Here, we report on the results of a replication study using the R statistical software package. We are able to verify most of their findings; however, some confidence intervals associated with breakpoints cannot be reproduced. These confidence intervals require computation of the quantiles of a nonstandard distribution, the distribution of the argmax functional of a certain stochastic process. Interestingly, the difficulties appear to be due to numerical problems in GAUSS, the software package used by Bai and Perron.
Series: Research Report Series / Department of Statistics and Mathematics
APA, Harvard, Vancouver, ISO, and other styles
7

Zheng, Pingping. "Bayesian analysis of structural change in trend." Thesis, Nottingham Trent University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391001.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Fröberg, Malvina. "Testing for Structural Change in Regression Models of Meat Consumption in Sweden." Thesis, Uppsala universitet, Tillämpad matematik och statistik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-318686.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Azam, Mohammad Nurul 1957. "Modelling and forecasting in the presence of structural change in the linear regression model." Monash University, Dept. of Econometrics and Business Statistics, 2001. http://arrow.monash.edu.au/hdl/1959.1/9152.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

黃少軍 and Shaojun Huang. "Service sector development, structural change, and economic growth: international experriences and implicationsfor China." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31241815.

Full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "Bioproducts; Structural change; Models"

1

Vilares, Manuel J. Structural Change in Macroeconomic Models. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4370-4.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Caballero, Jaime del Valle. Structural change and factor prices. Río Piedras, P.R: Unidad de Investigaciones Económicas, Departamento de Economía, Universidad de Puerto Rico, Recinto de Río Piedras, 1993.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

Structural change in macroeconomic models: Theory and estimation. Dordrecht: Martinus Nijhoff, 1986.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

McDonald, J. R. S. Structural change, measured labour productivity and input-output models. Loughborough: Loughborough University of Technology, Department of Economics, 1993.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

Baily, Martin Neil. Labor productivity: Structural change and cyclical dynamics. Cambridge, MA: National Bureau of Economic Research, 1996.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

Growth and structural change in large low-income countries. Washington, D.C., U.S.A: World Bank, 1986.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

Seiichi, Katayama. Import demand structural change in the Pacific basin countries. Kobe, Japan: Institute of Economic Research, Kobe University of Commerce, 1986.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

Bianchi, Marco. Time series modelling in the presence of structural change. Louvain-la-Neuve: CIACO, 1995.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

Lindén, Lena. Developmental change and linear structural equations: Applications of LISREL models. Stockholm: Almqvist & Wiksell International, 1986.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

A, Harris. Structural change in the manufacturing sectors of the Australian states. Murdoch, W.A: Murdoch University, 1990.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Book chapters on the topic "Bioproducts; Structural change; Models"

1

Tsurumi, Hiroki. "Abrupt and Gradual Structural Shifts in State-Space Models." In Economic Structural Change, 325–37. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-662-06824-3_20.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Claesson, Lennart, and Anders H. Westlund. "On the Estimation of Time-varying Parameters in Transfer Function Models." In Economic Structural Change, 301–24. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-662-06824-3_19.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Sen, Pranab K. "Interactive Poverty and Affluence of a Society: Change-Point Models for Structural Changes." In Economic Structural Change, 351–69. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-662-06824-3_22.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Phillips, Garry D. A., and Brendan P. M. McCabe. "A Sequential Approach to Testing for Structural Change in Econometric Models." In Econometrics of Structural Change, 87–101. Heidelberg: Physica-Verlag HD, 1989. http://dx.doi.org/10.1007/978-3-642-48412-4_8.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Leybourne, S. J., and B. P. M. McCabe. "Testing for Coefficient Constancy in Random Walk Models with Particular Reference to the Initial Value Problem." In Econometrics of Structural Change, 41–48. Heidelberg: Physica-Verlag HD, 1989. http://dx.doi.org/10.1007/978-3-642-48412-4_4.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

McArdle, John J., and John R. Nesselroade. "Analyses based on latent change score models." In Longitudinal data analysis using structural equation models., 119–32. Washington: American Psychological Association, 2014. http://dx.doi.org/10.1037/14440-010.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

McArdle, John J., and John R. Nesselroade. "Plotting bivariate latent change score results." In Longitudinal data analysis using structural equation models., 301–4. Washington: American Psychological Association, 2014. http://dx.doi.org/10.1037/14440-026.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Kleffe, Jürgen. "Updating Parameters of Linear Change Point Models." In Statistical Analysis and Forecasting of Economic Structural Change, 319–26. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-662-02571-0_20.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Harvey, Andrew C., and Garry D. A. Phillips. "Testing for Structural Change in Simultaneous Equation Models." In Statistical Analysis and Forecasting of Economic Structural Change, 25–36. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-662-02571-0_2.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

McArdle, John J., and John R. Nesselroade. "Analyses based on advanced latent change score models." In Longitudinal data analysis using structural equation models., 133–40. Washington: American Psychological Association, 2014. http://dx.doi.org/10.1037/14440-011.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Bioproducts; Structural change; Models"

1

Gangrade, Aditya, Bobak Nazer, and Venkatesh Saligrama. "Lower bounds for two-sample structural change detection in ising and Gaussian models." In 2017 55th Annual Allerton Conference on Communication, Control, and Computing (Allerton). IEEE, 2017. http://dx.doi.org/10.1109/allerton.2017.8262849.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Aida, Masaki, and Yuya Kakizawa. "Structural Change Models of Online Social Networks Caused by External Factors Like Mass Media." In 2019 IEEE Intl Conf on Dependable, Autonomic and Secure Computing, Intl Conf on Pervasive Intelligence and Computing, Intl Conf on Cloud and Big Data Computing, Intl Conf on Cyber Science and Technology Congress (DASC/PiCom/CBDCom/CyberSciTech). IEEE, 2019. http://dx.doi.org/10.1109/dasc/picom/cbdcom/cyberscitech.2019.00124.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Poon, S. K., G. Fan, J. Poon, and R. Young. "Analysis of Structural Change Point in Multivariate Regression Models: An Application on IT Productivity Impact." In 2008 IEEE 8th International Conference on Computer and Information Technology Workshops. CIT Workshops 2008. IEEE, 2008. http://dx.doi.org/10.1109/cit.2008.workshops.86.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Wai, Phoong Seuk, Sek Siok Kun, Mohd Tahir Ismail, Samsul Ariffin, and Abdul Karim. "Model performance between linear vector autoregressive and Markov switching vector autoregressive models on modelling structural change in time series data." In 2015 International Symposium on Mathematical Sciences and Computing Research (iSMSC). IEEE, 2015. http://dx.doi.org/10.1109/ismsc.2015.7594083.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Shirakawa, Noriyuki, Yasushi Uehara, Masanori Naitoh, Hidetoshi Okada, Yuichi Yamamoto, and Seiichi Koshizuka. "Next Generation Safety Analysis Methods for SFRs—(5) Structural Mechanics Models of COMPASS Code and Verification Analyses." In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75532.

Full text
Abstract:
A five-year research project started in FY2005 (Japanese Fiscal Year, hereafter) to develop a code based on the Moving Particle Semi-implicit (MPS) method for detailed analysis of core disruptive accidents (CDAs) in sodium-cooled fast reactors (SFRs). The code is named COMPASS (Computer Code with Moving Particle Semi-implicit for Reactor Safety Analysis). CDAs have been almost exclusively analyzed with SIMMER-III [2], which is a two-dimensional multi-component multi-phase Eulerian fluid-dynamics code, coupled with fuel pin model and neutronics model. The COMPASS has been developed to play a role complementary to SIMMER-III in temporal and spatial scale viewpoint; COMPASS for mesoscopic using a small window cut off from SIMMER-III for macroscopic. We presented the project’s outline and the verification analyses of elastic structural mechanics module of the COMPASS in ICONE16 [1]. The COMPASS solves physical phenomena in CDAs coupling fluid dynamics and structural dynamics with phase changes, that is vaporization/condensation and melting/ freezing. The phase changes are based on nonequilibrium heat transfer-limited model and all “phase change paths” considered in SIMMER-III are implemented [20]. In FY2007, the elastoplastic model including thermal expansion and fracture are formulated in terms of MPS method and implemented in the COMPASS, where the model adopts the von Mises type yield condition and the maximum principal stress as fracture condition. To cope with large computing time, “stiffness reduction approximation” was developed and successfully implemented in the COMPASS besides parallelization effort. Verification problems are set to be suitable for analyses of SCARABEE tests, EAGLE tests and hypothetical CDAs in real plants so that they are suggesting issues to be solved by improving the models and calculation algorithms. The main objective of SCARABEE-N in-pile tests was to study the consequences of a hypothetical total instantaneous blockage (TIB) at the entrance of a liquid-metal reactor subassembly at full power [21]. The main objectives of the EAGLE program consisting of in-pile tests using IGR (Impulse Graphite Reactor) and out-of-pile tests at NNC/RK are; 1) to demonstrate effectiveness of special design concepts to eliminate the re-criticality issue, and 2) to acquire basic information on early-phase relocation of molten-core materials toward cold regions surrounding the core, which would be applicable to various core design concepts [22, 23]. In this paper, the formulations and the results of functional verification of elastoplastic models in CDA conditions will be presented.
APA, Harvard, Vancouver, ISO, and other styles
6

Erturun, Ugur, and Karla Mossi. "A Feasibility Investigation on Improving Structural Integrity of Thermoelectric Modules With Varying Geometry." In ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/smasis2012-8247.

Full text
Abstract:
This study investigates the feasibility of improving the structural integrity of thermoelectric modules (TEMs) with varying geometry. For this purpose, six different TEM models with various thermoelectric leg geometries were designed and modeled in order to perform a thermal stress FEA using ANSYS Workbench. Temperature dependent material properties were used since some properties such as coefficients of thermal expansion change with temperature. Significant decrease in thermal stresses and leg deformations were observed with some models. Particularly, the cylindrical TE leg geometry model has approximately 54% lower Von Mises stresses (294MPa) and 13% lower TE leg deformations (3.9μm) than those of the typical TE leg geometry model (635MPa and 4.5μm). Power generation analyses of the models were performed to evaluate the effect of new TE leg geometries on the performance. TEM model with cylindrical TE leg geometry has the highest power generation (29.3mW) among all the models.
APA, Harvard, Vancouver, ISO, and other styles
7

Marinescu, Olguta, Bogdan I. Epureanu, and Mihaela Banu. "Reduced-Order Models of Mistuned Cracked Bladed Disks." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-38733.

Full text
Abstract:
Predicting the influence of cracks on the dynamics of bladed disks is a very important challenge. Cracks change the structural response, which in turn changes the crack propagation characteristics. Hence, accurate and computationally effective means to model the dynamics of cracked bladed disks and blisks is particularly crucial in applications such as prognosis, guidance for repairs, characterization after repairs, design, and structural health monitoring. Most current models of bladed disks exploit cyclic symmetry to gain computational efficiency. However, the presence of cracks and mistuning destroys that symmetry and makes computational predictions much more expensive. In this work, we propose a new reduced order modeling methodology which can speed up computations by several orders of magnitude. There are two key components of the new methodology. First, the displacements and deformations of the crack surfaces are not modeled in absolute coordinates but relative coordinates. That allows for an effective model reduction based on (fixed-interface Craig-Bampton) component mode synthesis (CMS). The use of relative coordinates allows one to define one of the components in CMS as the pristine/uncracked structure (with mistuning). This approach is used in combination with a set of accurate approximations for the constraint modes used in CMS. Second, the effects of mistuning are captured by component mode mistuning (CMM) which allows the construction of extremely efficient reduced order models for the pristine/uncracked component with mistuning. The novel proposed method is applied to a finite element model of an industrial blisk. The combined presence of mistuning and cracks is shown to have important effects. Also, the proposed approach is shown to provide accurate predictions for the overall blisk while requiring computations using single-sector models only. The influence of various parameters on the accuracy of the reduced order models is investigated. Overall, the results show a very good agreement between full finite element analyses and the proposed reduced order modeling approach.
APA, Harvard, Vancouver, ISO, and other styles
8

Zhao, Chengbi, Ming Ma, and Owen Hughes. "Applying Strip Theory Based Linear Seakeeping Loads to 3D Full Ship Finite Element Models." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10124.

Full text
Abstract:
Panel based hydrodynamic analyses are well suited for transferring seakeeping loads to 3D FEM structural models. However, 3D panel based hydrodynamic analyses are computationally expensive. For monohull ships, methods based on strip theory have been successfully used in industry for many years. They are computationally efficient, and they provide good prediction for motions and hull girder loads. However, many strip theory methods provide only hull girder sectional forces and moments, such as vertical bending moment and vertical shear force, which are difficult to apply to 3D finite element structural models. For the few codes which do output panel pressure, transferring the pressure map from a hydrodynamic model to the corresponding 3D finite element model often results in an unbalanced structural model because of the pressure interpolation discrepancy. To obtain equilibrium of an imbalanced structural model, a common practice is to use the “inertia relief” approach to rebalance the model. However, this type of balancing causes a change in the hull girder load distribution, which in turn could cause inaccuracies in an extreme load analysis (ELA) and a spectral fatigue analysis (SFA). This paper presents a method of applying strip theory based linear seakeeping pressure loads to balance 3D finite element models without using inertia relief. The velocity potential of strip sections is first calculated based on hydrodynamic strip theories. The velocity potential of a finite element panel is obtained from the interpolation of the velocity potential of the strip sections. The potential derivative along x-direction is computed using the approach proposed by Salvesen, Tuck and Faltinsen. The hydrodynamic forces and moments are computed using direct panel pressure integration from the finite element structural panel. For forces and moments which cannot be directly converted from pressure, such as hydrostatic restoring force and diffraction force, element nodal forces are generated using Quadratic Programing. The equations of motions are then formulated based on the finite element wetted panels. The method results in a perfectly balanced structural model.
APA, Harvard, Vancouver, ISO, and other styles
9

Page, Ana M., Karin Norén-Cosgriff, Kristoffer S. Skau, and Amir M. Kaynia. "REDWIN Foundation Models for Integrated Dynamic Analyses of Offshore Wind Turbines." In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-96168.

Full text
Abstract:
Abstract Due to the complex nature of the loads on Offshore Wind Turbines (OWTs), accurate and optimized design of these structures require integrated simulation tools that can properly capture the various structural interactions governing the response. Considerable progress has been made in recent years on developing proper models for coupled aerodynamic and hydrodynamic loads together with advanced control systems for turbines. These efforts have resulted in a suite of aero-servo-hydro-elastic numerical simulation codes available to the industry. However, proper foundation models have been lagging behind in these tools despite availability of various advanced nonlinear models for foundations in general. This has led to uneconomical design of OWTs that have consistently failed to reproduce the measured natural frequencies and can negatively affect the design and structural performance of OWTs. This paper presents a library of recently developed foundation models based on the theory of plasticity together with their verification against large-scale field test data. These models are cast in the framework of macro-elements that represent the nonlinear response of the soil-foundation system due to arbitrary coupled loads at the seabed. The paper also presents results of the numerical simulations of the dynamic response of a monopile-based OWT in the North Sea using an aero-servo-hydro-elastic code and comparison with the data collected from one of the instrumented OWTs in the field. It is further presented how the characteristics of the measured dynamic response change with loading over a long period and the way the response characteristics relate to the basic features of the developed models.
APA, Harvard, Vancouver, ISO, and other styles
10

Huseby, Arne Bang, Erik Vanem, and Bent Natvig. "A New Method for Environmental Contours in Marine Structural Design." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10053.

Full text
Abstract:
The environmental contour concept is often applied in marine structural design in conjunction with the Inverse First Order Reliability Method (IFORM). It allows for the great advantage of considering the environmental loads independently of the structural response. In this way, design sea states may be identified along the contour and time consuming response calculations are only needed for a limited set of design sea states. The traditional way of establishing such environmental contour lines is by applying the Rosenblatt transformation and identify the circle (in two dimensions) with radius equal to the reliability index βr The points along this circle are then transformed back to the original environmental space, specifying the closed contour. In this paper, an alternative approach for establishing the environmental contour lines in the original environmental space is proposed, eliminating the need for any transformations. This approach utilizes Monte Carlo simulations of the joint environmental model and is generally found to perform well. Advantages are that it yields a more precise interpretation and allows for more flexible modelling of the environmental parameters. This makes it easier to modify the environmental models to account for effects such as climate change if this is desired. In addition, possible over- or underestimation of failure probabilities due to the Rosenblatt transformation inherent in the traditional approach can be avoided with the proposed method.
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Bioproducts; Structural change; Models"

1

Rahmani, Mehran, and Manan Naik. Structural Identification and Damage Detection in Bridges using Wave Method and Uniform Shear Beam Models: A Feasibility Study. Mineta Transportation Institute, February 2021. http://dx.doi.org/10.31979/mti.2021.1934.

Full text
Abstract:
This report presents a wave method to be used for the structural identification and damage detection of structural components in bridges, e.g., bridge piers. This method has proven to be promising when applied to real structures and large amplitude responses in buildings (e.g., mid-rise and high-rise buildings). This study is the first application of the method to damaged bridge structures. The bridge identification was performed using wave propagation in a simple uniform shear beam model. The method identifies a wave velocity for the structure by fitting an equivalent uniform shear beam model to the impulse response functions of the recorded earthquake response. The structural damage is detected by measuring changes in the identified velocities from one damaging event to another. The method uses the acceleration response recorded in the structure to detect damage. In this study, the acceleration response from a shake-table four-span bridge tested to failure was used. Pairs of sensors were identified to represent a specific wave passage in the bridge. Wave velocities were identified for several sensor pairs and various shaking intensities are reported; further, actual observed damage in the bridge was compared with the detected reductions in the identified velocities. The results show that the identified shear wave velocities presented a decreasing trend as the shaking intensity was increased, and the average percentage reduction in the velocities was consistent with the overall observed damage in the bridge. However, there was no clear correlation between a specific wave passage and the observed reduction in the velocities. This indicates that the uniform shear beam model was too simple to localize the damage in the bridge. Instead, it provides a proxy for the overall extent of change in the response due to damage.
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Bioproducts; Structural change; Models' for particular source types:
Journal articles Dissertations / Theses Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography