J Fail. Anal. and Preven. (2012)12: 267-272 DOI10.1007/sl1668-0129555-3 TECHNICAL ARTICLE-PEER-REVIEWED mpact Simulation on Ductile Metal Pipe with Polymer Coating by a coupled finite element and meshfree Method Yi Gong Zhen-Guo Yang. Yu-Fei Wang Submitted: 12 September 2011/in revised form: 4 January 2012/Published online: 13 March 2012 C ASM International 2012 Abstract It is common knowledge that conventional exchange in petrochemical and power generation industries finite element method(FEM) has intrinsic limitations in [1, 2]. Its effect, particularly on the pipes in the familiar nalyzing large deformation problems like high-velocity form of metal substrate and with polymer coating for, impact, explosion, etc. because of mesh distortion and respectively, imparting structural strength and corrosion tangling: while these problems can be easily avoided by the resistance, deserves to be studied in-depth for prevention of meshfree method (MM), the latter involves greater com- failures like erosion damage [3], and even separation putation time. Therefore, in this article, in order to between two such parts. In general, research studies on simultaneously utilize the respective advantages of the two impact behavior on materials involve two types of methods nethods, a coupled simulation method between both FEM experiments and numerical simulations. In terms of the and MM was employed to analyze the high-velocity impact former one, a wealth of analytic models and relevant pre- on ductile metal pipe with polymer coating. The impacted diction equations has been obtained and reported, but most area with large deformation was discretized by SPH of them have limited applications since they are not able to (smoothed particle hydrodynamics) particles, a classic cover all kinds of target materials, e. g, ductile or brittle meshfree model and the re g section was modeled by [4, 5], with or without coatings [6]. As for the latter one, FEM meshes. By this method, the interfacial shear stresses besides the common superiorities like cost-, effort-, and between the coating and the substrate and the residual time-saving properties, finer meshes and less computation stresses beneath the contact points were studied, which times can be usually achieved by means of the prevailing results were compared with sole FEM and MM too loss of the targets and the final morphologies of their sur faces[9-12]. Nevertheless, the simplified 2D FEM model Keywords Finite nt· Meshfree has to obey certain assumptions as plane strain, plane stress, Smoothed particle amIcs(SPH)·Im axisymmetric, etc, and has the difficulty to solve the problem of multi-particle impact: the 3D FEM model also has its own limitations when under high-velocity impact, Introduction such as distortion of Lagrange meshes during large defor mation, and decrease of simulation accuracy due to cess that hits targets with oarseness of the 3D grids force and causes degradation on their surfaces, is a common In recent decades. the methods(△MMs)[13 action on pipes with applications in fluid delivery and heat gridless models of which relized by a set of scat- tered particles rather than of continuous meshes have been rapidly developed for specific applications iong. Z.-G. Yang(<) Department of Materials Science, Fudan University including crack propagation [14, 15], large deformation, Shanghai 200433, People's Republic of China explosion, fluids [16], impact [17, 18], and so on, which are e-mail:zgyang@fudan.edu.cn always encountered with mesh distortion and tanglin SpringTECHNICAL ARTICLE—PEER-REVIEWED Impact Simulation on Ductile Metal Pipe with Polymer Coating by a Coupled Finite Element and Meshfree Method Yi Gong • Zhen-Guo Yang • Yu-Fei Wang Submitted: 12 September 2011 / in revised form: 4 January 2012 / Published online: 13 March 2012 ASM International 2012 Abstract It is common knowledge that conventional finite element method (FEM) has intrinsic limitations in analyzing large deformation problems like high-velocity impact, explosion, etc. because of mesh distortion and tangling; while these problems can be easily avoided by the meshfree method (MM), the latter involves greater com￾putation time. Therefore, in this article, in order to simultaneously utilize the respective advantages of the two methods, a coupled simulation method between both FEM and MM was employed to analyze the high-velocity impact on ductile metal pipe with polymer coating. The impacted area with large deformation was discretized by SPH (smoothed particle hydrodynamics) particles, a classic meshfree model, and the remaining section was modeled by FEM meshes. By this method, the interfacial shear stresses between the coating and the substrate and the residual stresses beneath the contact points were studied, which would have referenced values in analyzing failure modes of components with similar composite structure. Then, the results were compared with sole FEM and MM too. Keywords Finite element Meshfree Smoothed particle hydrodynamics (SPH) Impact Introduction Impact, the dynamic process that hits targets with great force and causes degradation on their surfaces, is a common action on pipes with applications in fluid delivery and heat exchange in petrochemical and power generation industries [1, 2]. Its effect, particularly on the pipes in the familiar form of metal substrate and with polymer coating for, respectively, imparting structural strength and corrosion resistance, deserves to be studied in-depth for prevention of failures like erosion damage [3], and even separation between two such parts. In general, research studies on impact behavior on materials involve two types of methods: experiments and numerical simulations. In terms of the former one, a wealth of analytic models and relevant pre￾diction equations has been obtained and reported, but most of them have limited applications since they are not able to cover all kinds of target materials, e.g., ductile or brittle [4, 5], with or without coatings [6]. As for the latter one, besides the common superiorities like cost-, effort-, and time-saving properties, finer meshes and less computation times can be usually achieved by means of the prevailing two-dimensional (2D) finite element method (FEM) [7, 8], while the 3D FEM model could even give the real weight loss of the targets and the final morphologies of their sur￾faces [9–12]. Nevertheless, the simplified 2D FEM model has to obey certain assumptions as plane strain, plane stress, axisymmetric, etc., and has the difficulty to solve the problem of multi-particle impact; the 3D FEM model also has its own limitations when under high-velocity impact, such as distortion of Lagrange meshes during large defor￾mation, and decrease of simulation accuracy due to coarseness of the 3D grids. In recent decades, the meshfree methods (MMs) [13], gridless models of which are discretized by a set of scat￾tered particles rather than a series of continuous meshes, have been rapidly developed for specific applications including crack propagation [14, 15], large deformation, explosion, fluids [16], impact [17, 18], and so on, which are always encountered with mesh distortion and tangling Y. Gong Z.-G. Yang (&) Y.-F. Wang Department of Materials Science, Fudan University, Shanghai 200433, People’s Republic of China e-mail: zgyang@fudan.edu.cn 123 J Fail. Anal. and Preven. (2012) 12:267–272 DOI 10.1007/s11668-012-9555-3