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Improvement of Cold Recycled Mixture Performance Based on Improved Density Test Method and RAP Characteristics

Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 79-87页

作者： HAN Zhanchuang PANG Yafeng lin hongwei China First Highway Engineering Group Co. LtdBeijing 100024China The Key Laboratory of Road and Traffic Engineering Ministry of EducationTongji UniversityShanghai 201804China Guangzhou Baiyun International Airport Co. Ltd.Guangzhou 510470China

The available test methods for optimal moisture content of cold recycled mixture(CRM)as well as its bulk specific gravity,and theoretical maximum relative density were analyzed in this *** test improvements were suggested to improve test control of the CRM road performance based on the discovered ***,the properties of reclaimed asphalt pavement(RAP),including the content of old asphalt,penetration index,passing rate of 4.75 mm sieve,and gradation change rate after extraction,were *** effects of RAP characteristics on splitting tensile strength,water stability,the high-and low-temperature performance of emulsified asphalt CRM were *** results show that the optimum moisture content of CRM should be determined when the compaction work matches the specimen’s molding *** the analyzed methods of bulk specific gravity assessment,the dry-surface and CoreLok methods provide more robust and accurate results than the wax-sealing method,while the dry-surface method is the most *** modified theoretical maximum relative density test method is proposed,which can reduce the systematic error of the vacuum test *** following RAP-CRM trends can be *** lower the content of old asphalt and the smaller the change rate of gradation,the smaller the voids and the better the water stability of *** greater the penetration of old asphalt,the higher the fracture work and low-temperature splitting *** greater the penetration,the higher the passing rate of 4.75 mm sieve after extraction,and the worse the high-temperature performance of CRM.

关键词： RAP volume parameters high-temperature performance low-temperature performance water stability

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New Perspective to Isogeometric Analysis:Solving Isogeometric Analysis Problem by Fitting Load Function

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Computer Modeling in Engineering & Sciences 2023年第9期136卷 2957-2984页

作者： Jingwen Ren hongwei lin School of Mathematical Sciences Zhejiang UniversityHangzhou310058China State Key Lab.of CAD&CG Zhejiang UniversityHangzhou310058China

Isogeometric analysis(IGA)is introduced to establish the direct link between computer-aided design and *** is commonly implemented by Galerkin formulations(isogeometric Galerkin,IGA-G)through the use of nonuniform rational B-splines(NURBS)basis functions for geometric design and *** promising approach,isogeometric collocation(IGA-C),working directly with the strong form of the partial differential equation(PDE)over the physical domain defined by NURBS geometry,calculates the derivatives of the numerical solution at the chosen collocation *** a typical IGA,the knot vector of the NURBS numerical solution is only determined by the physical domain.A new perspective on the IGAmethod is proposed in this study to improve the accuracy and convergence of the *** the PDE with IGA can be regarded as fitting the load function defined on the NURBS geometry(right-hand side)with derivatives of the NURBS numerical solution(left-hand side).Moreover,the design of the knot vector has a close relationship to theNURBS functions to be fitted in the area of data fitting in geometric ***,the detected feature points of the load function are integrated into the initial knot vector of the physical domainto construct thenewknot vector of thenumerical ***,they are connected seamlessly with the IGA-C framework for its great potential combining the accuracy and smoothness merits with the computational efficiency,which we call isogeometric collocation by fitting load function(IGACL).In numerical experiments,we implement our method to solve 1D,2D,and 3D PDEs and demonstrate the improvement in accuracy by comparing it with the standard IGA-C *** also verify the superiority in the accuracy of our knot selection scheme when employed in the IGA-G method,which we call isogeometric Galerkin by fitting load function(IGA-GL).

关键词： Isogeometric analysis collocation methods feature point detection knot vector

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The Convergence of Least-Squares Progressive Iterative Approximation for Singular Least-Squares Fitting System

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Journal of Systems Science & Complexity 2018年第6期31卷 1618-1632页

作者： lin hongwei CAO Qi ZHANG Xiaoting School of Mathematical Science State Key Laboratory of CAD&CG Zhejiang University

Data fitting is an extensively employed modeling tool in geometric design. With the advent of the big data era, the data sets to be fitted are made larger and larger, leading to more and more least-squares fitting systems with singular coefficient matrices. LSPIA (least-squares progressive iterative approximation) is an efficient iterative method for the least-squares fitting. However, the convergence of LSPIA for the singular least-squares fitting systems remains as an open problem. In this paper, the authors showed that LSPIA for the singular least-squares fitting systems is convergent. Moreover, in a special case, LSPIA converges to the Moore-Penrose (M-P) pseudo-inverse solution to the least- squares fitting result of the data set. This property makes LSPIA, an iterative method with clear geometric meanings, robust in geometric modeling applications. In addition, the authors discussed some implementation detail of LSPIA, and presented an example to validate the convergence of LSPIA for the singular least-squares fitting systems.

关键词： Data fitting geometric modeling LSPIA singular least-squares fitting system.

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Trivariate B-spline solid construction by pillow operation and geometric iterative fitting

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Science China(Information Sciences) 2018年第11期61卷 232-234页

作者： hongwei lin Hao HUANG Chuanfeng HU School of Mathematical Science State Key Laboratory of CAD&CG Zhejiang University

While the traditional geometric design community focuses on the design of curves and surfaces, the advent of isogeometric analysis (IGA)[1] has made the development of methods for designing trivariate B-spline solids (TBSs) imperative. In IGA, a valid TBS should have a positive Jacobian value at every point in its domain. A negative Jacobian value at any point in the domain of the TBS can render the IGA invalid.

关键词： TBS Trivariate B-spline solid construction by pillow operation and geometric iterative fitting GFD Figure

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3D shape retrieval based on Laplace operator and joint Bayesian model

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Visual Informatics 2020年第3期4卷 69-76页

作者： Wang Zihao lin hongwei School of Mathematics Zhejiang UniversityHangzhou 310027China State Key Laboratory of CAD&CG Zhejiang UniversityHangzhou 310058China

Feature analysis plays a significant role in computer vision and computer *** the task of shape retrieval,shape descriptor is *** recent years,feature extraction based on deep learning becomes very popular,but the design of geometric shape descriptor is still meaningful due to the contained intrinsic information and *** paper proposes an effective and robust descriptor of 3D *** descriptor is constructed based on the probability distribution of the normalized eigenfunctions of the Laplace–Beltrami operator on the surface,and a spectrum method for dimensionality *** distance metric of the descriptor space is learned by utilizing the joint Bayesian model,and we introduce a matrix regularization in the training stage to re-estimate the covariance ***,we apply the descriptor to 3D shape retrieval on a public *** show that our method is robust and has good retrieval performance.

关键词： Laplace-Beltrami operator Joint Bayesian Shape retrieval

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Isogeometric Analysis-Based Topological Optimization for Heterogeneous Parametric Porous Structures

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Journal of Systems Science & Complexity 2023年第1期36卷 29-52页

作者： HU Chuanfeng HU Hui lin hongwei YAN Jiacong School of Mathematical Sciences State Key Lab.of CAD&CGZhejiang UniversityHangzhou 310027China

Porous structures widely exist in nature and artifacts,which can be exploited to reduce structural weight and material usage or improve damage tolerance and energy *** this study,the authors develop an approach to design optimized porous structures with Triply Periodic Minimal Surfaces(TPMSs)in the framework of isogeometric analysis(IGA)-based topological *** the developed method,by controlling the density distribution,the designed porous structures can achieve the optimal mechanical performance without increasing the usage of ***,the implicit functions of the TPMSs are adopted to design several types of porous elements ***,to reduce the cost of computation,the authors propose an equivalent method to forecast the elastic modulus of these porous elements with different ***,the relationships of different porous elements between the elastic modulus and the relative density are ***,the IGA-based porous topological optimization is developed to obtain an optimal density distribution,which solves a volume constrained compliance minimization problem based on ***,an optimum heterogeneous porous structure is generated based on the optimized density *** results demonstrate the effectiveness and efficiency of the proposed method.

关键词： B-spline solid heterogeneous porous structure isogeometric analysis topological optimization triply periodic minimal surface

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Diffusion curves with diffusion coefficients

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Computational Visual Media 2018年第2期4卷 149-160页

作者： hongwei lin Jingning Zhang Chenkai Xu School of Mathematical Science Zhejiang University State Key Laboratory of CAD&CG Zhejiang University

Diffusion curves can be used to generate vector graphics images with smooth variation by solving Poisson equations. However, using the classical diffusion curve model, it is difficult to ensure that the generated diffusion image satisfies desired constraints. In this paper, we develop a model for producing a diffusion image by solving a diffusion equation with diffusion coefficients, in which color layers and coefficient layers are introduced to facilitate the generation of the diffusion image. Doing so allows us to impose various constraints on the diffusion image, such as diffusion strength, diffusion direction,diffusion points, etc., in a unified computational framework. Various examples are presented in this paper to illustrate the capabilities of our model.

关键词： diffusion curves diffusion coefficients color layers coefficient layers vector graphics

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Isogeometric Least-Squares Collocation Method with Consistency and Convergence Analysis

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Journal of Systems Science & Complexity 2020年第5期33卷 1656-1693页

作者： lin hongwei XIONG Yunyang WANG Xiao HU Qianqian REN Jingwen School of Mathematical Science State Key Lab.of CAD&CGZhejiang UniversityHangzhou 310027China Department of Mathematics Zhejiang Gongshang UniversityHangzhou 310018China

This paper presents the isogeometric least-squares collocatio method,which determines the numerical solution by making the approximate differential operator fit the real differential operator in a least-squares *** number of collocation points employed in IGA-L can be larger than that of the *** analysis and numerical examples presented in this paper show the superiority of IGA-L over state-of-the-art collocation ***,a small increase in the number of collocation points in IGA-L leads to a large improvement in the accuracy of its numerical ***,IGA-L method is more flexible and more stable,because the number of collocation points in IGA-L is ***,IGA-L is convergent in some cases of singular ***,the consistency and convergence analysis are also developed in this paper.

关键词： Collocation method consistency and convergence least-squares fitting isogeometric analysis NURBS

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A computational model of topological and geometric recovery for visual curve completion

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Computational Visual Media 2016年第4期2卷 329-342页

作者： hongwei lin Zihao Wang Panpan Feng Xingjiang Lu Jinhui Yu School of Mathematical Science Zhejiang University State Key Laboratory of CAD&CG Zhejiang University

Visual curve completion is a fundamental problem in understanding the principles of the human visual system. This problem is usually divided into two problems: a grouping problem and a shape *** one hand, though perception of the visually completed curve is clearly a global task(for example,a human perceives the Kanizsa triangle only when seeing all three black objects), conventional methods for solving the grouping problem are generally based on local Gestalt laws. On the other hand, the shape of the visually completed curve is usually recovered by minimizing shape energy in existing ***, not only do these methods lack mechanisms to adjust the shape of the recovered visual curve using perceptual, psychophysical, and neurophysiological knowledge, but it is also difficult to calculate an explicit representation of the visually completed curve. In this paper, we present a systematic computational model for generating a visually completed curve. Firstly, based on recent studies of perception, psychophysics, and neurophysiology, we formulate a grouping procedure based on the human visual system by seeking a minimum Hamiltonian cycle in a graph, solving the grouping problem in a global manner. Secondly, we employ a B′ezier curve-based model to represent the visually completed curve. Not only is an explicit representation deduced, but we also present a means to integrate knowledge from related areas, such as perception, psychophysics, and neurophysiology, and so on. The proposed computational model has been validated using many modal and amodal completion examples, and desirable results were obtained.

关键词： modal completion amodal completion grouping problem shape problem human visual system

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Preparation and Properties of Bio-Based Flame Retardant L-APP/Poly(L-lactic acid)Composites

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Journal of Renewable Materials 2021年第12期9卷 2067-2076页

作者： Qionglin Luo Mingliang Wang Hui Zhang Yuejun Ouyang hongwei lin You Shu Shengpei Su Hunan Engineering Laboratory for Preparation Technology of Polyvinyl Alcohol Fiber Material Huaihua UniversityHuaihua418000China National and Local Joint Engineering Laboratory for New Petro-Chemical Materials and Fine Utilization of Resources Hunan Normal UniversityChangsha410081China

Poly(L-lactic acid)(PLLA)is a thermoplastic material with complete degradability,high biocompatibility and excellent mechanical *** can replace petroleum-based polymers are currently being used in the fields of packaging,agriculture,textiles,medical and so ***,PLLA’s extremely flammability greatly limits its wider *** bio-based flame retardant L-APP/PLLA composites was prepared by melt blending of the L-APP and *** morphology,impact properties,thermal properties and flame retardant properties of composites were investigated by field emission scanning electron microscope(SEM),impact tester,differential scanning calorimeter(DSC),thermogravimetric analyzer(TGA),limiting oxygen indexer(LOI)and horizontalvertical burning *** results showed that the degree of crystallization(X_(c))and LOI of L-APP/PLLA composites increased as increasing of L-APP ***’s more,the impact strength first increased and then decreased,the glass transition temperature(T_(g))and melting temperature(T_(m))do not changed *** impact strength of composites was 9.1 kJ/m^(2) at a 5 wt%loading for L-APP,which was the highest *** the content of L-APP was 20%,the LOI was 30.8%,the Xc was 42.3%and the UL-94 level was *** research can promote the value-added utilization of lignin and the application of PLLA in the fields of flame retardant materials.

关键词： Bio-based flame retardant lignin ammonium polyphosphate poly(L-lactic acid)

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