Complex Stress State Research Articles

Mechanical behaviour and constitutive modelling of an additively manufactured stereolithography polymer

Additive manufacturing enables the production of complex structures not possible with traditional methods. Such structures are attractive for use in various engineering applications. It follows that knowledge about the mechanical response of additive manufactured materials, and how to model it numerically, is required. In this work, a polymer manufactured with the stereolithography (SLA) method was studied through tensile and compression testing of smooth and notched specimens. The material exhibited an initial linear elastic behaviour followed by strain-rate- and pressure-dependent inelastic flow before failing at rather large strains in a brittle fracture mode. Motivated by the observed material behaviour, a hyper-viscoelastic constitutive model with a brittle fracture criterion was developed, implemented in a commercial finite element software, and calibrated to the material tests. Compression tests of lattice structures were performed and simulated to validate the model’s capabilities at complex stress states. The model captured the experimentally observed nonlinear stress–strain behaviour, and predicted the fracture initiation and a failure mode similar to the experimental results.

Influence of Temperature and Long-Term Operation on Metal Durability of Pipelines of Hydrotechnical Structures

The paper considers the issue of the influence of ambient temperature and service life on the endurance of pipe steels of underground pipelines. The results of numerous experimental studies allowed us to draw the following conclusions. An analysis of the experimental data indicates that for all the studied steels, the endurance decreases with decreasing air temperature, mainly down to-20... -30 °C. This can be explained by the embrittlement of the metal, i.e. a decrease in the plastic properties of the pipeline metal structure. In addition, it can be seen from the given data that low-alloy steels 48KhN, 09G2S, 10GS have the highest endurance. Weak endurance is mainly typical of grade 20 carbon steel. Experimental studies show that with an increase in the service life of pipes, their endurance decreases, and this tendency is inherent in all the studied steels. Studies of the endurance of pipe steels under complex stress states show that static torsional stresses close to the yield strength, when tested in the air, do not reduce fatigue life. Although the corrosive environment significantly reduces the cyclic strength of steel under shear stresses up to τcr=05τY, the conditional limit of corrosion fatigue is not lower than when tested for corrosion fatigue under the action of only alternating stresses in a symmetrical cycle. It could be considered that the torsional stress in the pipeline system does not exceed 10 MPa. In that case, their influence on practical calculations on the endurance of pipes of underground pipeline systems can be neglected.

Pseudo-anisotropic damage model of randomly oriented strands (ROS) for reproducing flexural damage behavior

We developed a pseudo-anisotropic damage model of randomly oriented strands (ROS) reinforced thermoplastic composites for reproducing flexural deformation and damage behavior by finite element analysis (FEA). The damage model applied stress triaxiality to capture the differences in the damage initiations among the tensile, compressive, and shear stress states. The damage model also included equivalent damage propagation function depending on the interlaminar shear property of ROS. The developed FE model was focused on the characteristics that ROS composites show macroscopic in-plane isotropic and out-of-plane anisotropic mechanical properties because of the laminated structure of ROS. Furthermore, all of the material parameters in the FE model were identified by performing simple deformation tests. As a result, the flexural numerical simulation could reproduce the experimental flexural deformation and damage behaviors of ROS plates with different thickness despite a complex stress state including in-plane and out-of-plane stresses. The developed FE model has potential to evaluate the safety of ROS-manufactured structural components. The evaluation of safety by FEA constructed in this study can improve the applicability of ROS composites.

Phase field to fracture analysis on engineered cementitious composites under complex stress states

By developing multiple fine cracks before fracture failure, engineered cementitious composites (ECC) exhibit “metal-like” tensile behaviour, overcoming the inherent brittleness of concrete materials. For promoting the applications of ECC in enhancing structural resilience, it calls for a comprehensive understanding on its performance under complex stress states. To this end, a numerical method, based on phase field to ductile fracture, is developed to study the unique failure mechanism of ECC. A novel concept of pseudo plastic strain is proposed to account for the multi-cracking guided ductility of ECC, circumventing the numerical difficulty in describing multiple fine cracks. In addition, the influence of stress state history on the failure process of ECC members is included by degrading the material fracture toughness with a stress-weighted ductile fracture model. The robustness of proposed method is first verified against three laboratory benchmarks under designated stress conditions. ECC beam members of different test setups, to achieve mixed-mode fracture under complex stress states, are then investigated to fully demonstrate the capability of the developed model. This study is poised to pave way for better analysis and design of ECC members for versatile structural uses.

Numerical parametric evaluation of ultimate resistance of high-strength bolts

High strength bolts are widely used in the engineering field due to their good compressive properties. Accurate assessment of the ultimate capacity performance of high strength bolts under combined loading is essential to ensure the safety of steel structures in the connection zone. Existing studies are not sufficiently clear on the economic and condition-specific limits on the effects of various factors on high-strength bolts under complex stress conditions. In response to these problems, the aim of this paper is to analyse the effects of different factors on the load-bearing performance of high-strength bolts on the basis of numerical simulations. The mesoscale critical plastic strain (MCEPS) method was used on the model fracture and the accuracy of the model evaluation was verified. The effects of grade, type, diameter and bolt hole clearance on the ductile fracture behaviour of high-strength bolts were investigated. It was found that fully threaded bolts and through-hole clearances can mainly affect the load-bearing properties of high-strength bolts and increase the bolt's fracture-deformation capacity. The load-bearing performance of high-strength bolts under the influence of different factors was also compared with the Eurocode design (EC3) predictions.

Effect of Geometric Parameters on the Behavior of Eccentric RC Beam–Column Joints

Over the last century, the seismic behavior of reinforced concrete (RC) beam–column joints has drawn many researchers’ attention due to their complex stress state. Such joints should possess sufficient capacity and ductility to ensure integrity and safety when subjected to cyclic loading during seismic events. In the literature, while most studies have focused on the behavior of concentric beam–column joints, few studies investigated the response of eccentric beam–column joints, in which the beam’s centerline is offset from the centerline of the column. Recent earthquakes demonstrated severe damage in eccentric beam–column joints due to their brittle torsional behavior, which may threaten the ductility required for the overall structural performance. To investigate the effect of brittle failure on the strength, ductility, and stability of eccentric beam–column joints, nonlinear finite element (FE) models were developed and validated. The FE model was employed to study the effect of some geometric parameters on the global and local behaviors of beam–column joints, including the joint type (exterior and interior), the column aspect ratio, and the joint aspect ratio. The results show that the joint aspect ratio, which is the ratio of beam-to-column depth, has a predominant effect on the failure behavior of the joint. Additionally, the increase in column aspect ratio alters the failure mode from brittle joint shear failure to ductile beam-hinge, although there is an increase in the joint torsional moment. The current study also showed that interior joints exhibited a higher out-of-plane moment as well as more extensive column torsion cracks compared to exterior joints.

Mechanical Performances Analysis and Prediction of Short Plant Fiber-Reinforced PLA Composites.

Plant fiber-reinforced polylactic acid (PLA) exhibits excellent mechanical properties and environmental friendliness and, therefore, has a wide range of applications. This study investigated the mechanical properties of three short plant fiber-reinforced PLA composites (flax, jute, and ramie) using mechanical testing and material characterization techniques (SEM, FTIR, and DSC). Additionally, we propose a methodology for predicting the mechanical properties of high-content short plant fiber-reinforced composite materials. Results indicate that flax fibers provide the optimal reinforcement effect due to differences in fiber composition and microstructure. Surface pretreatment of the fibers using alkali and silane coupling agents increases the fiber-matrix interface contact area, improves interface performance, and effectively enhances the mechanical properties of the composite. The mechanical properties of the composites increase with increasing fiber content, reaching the highest value at 40%, which is 38.79% higher than pure PLA. However, further increases in content lead to fiber agglomeration and decreased composite properties. When the content is relatively low (10%), the mechanical properties are degraded because of internal defects in the material, which is 40.42% lower than pure PLA. Through Micro-CT technology, the fiber was reconstructed, and it was found that the fiber was distributed mainly along the direction of injection molding, and the twin-screw process changes the shape and length of the fiber. By introducing the fiber agglomeration factor function and correcting the Halpin-Tsai criterion, the mechanical properties of composite materials with different contents were successfully predicted. Considering the complex stress state of composite materials in actual service processes, a numerical simulation method was established based on transversely isotropic material using the finite element method combined with theoretical analysis. The mechanical properties of high-content short plant fiber-reinforced composite materials were successfully predicted, and the simulation results showed strong agreement with the experimental results.

An elastoplastic damage constitutive model for capturing dynamic enhancement effect of rock and concrete through equivalent stress history

The strength enhancement effect of rock and concrete under dynamic loading is one of the significant response characteristics differing from quasi-static loading. Typically, current dynamic constitutive models describe this phenomenon by adopting strain/stress rate dependent functions. In this study, a novel elastoplastic damage constitutive model that captures the dynamic strength increase through the equivalent stress history is developed by coupling the incubation characteristic time (ICT) criterion and the unified strength theory (UST). Specifically, the ICT criterion substitutes the stress history for the strain/stress rate to predict dynamic yield strength of rock and concrete. And the equivalent stress expressed by the UST provide an appropriate selection of the stress history in the ICT criterion under complex stress states. Furthermore, based on the non-associated plastic flow rule and the plastic-damage evolution law, combined with the equation of state, the proposed constitutive model is established and implemented numerically. The dynamic stress-strain curves of granite were reconstructed by a series of numerical tests on a single element, which verified the accuracy of the proposed constitutive model and the reliability of the numerical algorithm by comparing the experimental data. The proposed model was applied to the numerical simulation of dynamic compression-shear tests on inclined sandstone specimens loading by the split Hopkinson pressure bar (SHPB) and fragmentation experiments of single borehole granite specimens under blast loading, respectively. And the experimental dynamic crack patterns on the specimen surface captured by high-speed cameras match the simulated damage distribution well. In addition, several common concrete constitutive models and the proposed model were employed to simulate the dynamic response of reinforced concrete beams under near-field blast loading. The damage patterns and the mid-span residual displacement calculated numerically by the proposed model are more consistent with the experiments than other concrete models. As a conclusion, the proposed model, coupled the ICT criterion and the UST, provides a new perspective and paradigm for characterizing the responses of rock and concrete subjected to intense dynamic loads.

Static and dynamic mechanical behaviors of bamboo scrimber under combined tension-bending

Bamboo scrimber is a material with significant potential in the construction industry. In the context of its application as a beam structure, bamboo scrimber experiences combined tension-bending rather than single load. Furthermore, potential factors such as earthquakes, crosswinds, and progressive collapse events can induce static and dynamic deformations at varying loading rates in the structure. Up to now, the static and dynamic deformation behavior of bamboo scrimber under combined tension-bending has not been fully understood. The aim of this study is to investigate the effects of loading rate and pre-tension force on the mechanical behavior of bamboo scrimber through experimental research. The experimental results show that, both loading rate and pre-tension force will impact the mechanical behaviors of bamboo scrimber. Increasing the loading rate leads to an increase in the maximum bending load, bending fracture deflection, total fracture strain, and total dissipated energy. Increasing the pre-tension force will cause an increase in the maximum bending load, effective bending modulus, and total dissipated energy. The fracture positions become more random with the increase in pre-tension force. SEM fracture analysis shows loading rates and pre-tension forces has significant influences on the fracture mechanism. The fracture mode transitions from delamination dominated to fiber/matrix fracture dominated as pre-tension force rises from 0 N to 6000 N. This research offers valuable guidance for the practical implementation of bamboo scrimber beam in engineering applications. The findings provide data support for the design of fiber-reinforced composite and biomimetic bamboo structures subjected to complex stress conditions.

Strength properties of unidirectional laminated engineered bamboo boards under off-axis tension and compression tests

The strength properties of 30-mm unidirectional laminated engineered bamboo boards under off-axis tension and compression tests at seven different loading directions were studied in this research. The different failure modes, stress-displacement curves, and the corresponding full-field surface strain field measured through the digital image correlation (DIC) method were reported. The probability plots of off-axis strength values and the estimated characteristic strength values were given. Based on the original test data, the strength criteria based on Tsai and Wu theory was developed for the engineered bamboo panels studied herein. The values of strength tensors Fi and Fij were estimated based on the test results, which can be used to accurately model engineered bamboo products under complex stress conditions such as joint or notch regions. The characteristic off-axis strength values based on the Hankinson's formula given by the current standards are suggested to be further calibrated for design applications.

Study on In-Plane Initial Rotational Stiffness of Eccentric RHS Beam-Column Joints.

The eccentric RHS (rectangular hollow sections) joint offers improved mechanical properties and better space utilization. Its use in frame structures has gained significant attention. Currently, the initial rotational stiffness of RHS joints, the simplified finite element analysis method of eccentric RHS joints, and the influence of the spatial effect of RHS joints are still unknown. The purpose of this research is to establish a calculation formula for the initial rotational stiffness of eccentric RHS joints, study the influence of the spatial effect under complex stress conditions, and propose a mathematical model that can be used to simplify the analysis of eccentric RHS joints. The research findings indicate that the web plate's deformation stiffness primarily influences the joints' initial rotational stiffness. This increases with a higher beam-to-column depth-to-width ratio, beam-to-column thickness ratio, and column width-to-thickness ratio. The form of the moment distribution in the joint changes, and begins to have a significant effect on the rotational stiffness when the beam-to-column flange width ratio reaches and exceeds 0.7. The stiffeners have a direct additive effect on the joint stiffness. The influence of adjacent beams on the joint is minimal, and the spatial effect of the joint can be disregarded. Furthermore, the finite element analysis confirmed the accuracy of the power function model in accurately simulating the static load behavior of the joint, particularly the bending moment-angle relationship.

A refined finite element model for UHPC-filled FRP tube column

A sound finite element model is essential for the nonlinear structural analysis of FRP tube-confined UHPC columns, wherein an accurate constitutive model to characterize the mechanical behavior of UHPC under passive constraints is of utmost importance. This study presents a refined finite element modeling methodology for the UHPC-filled FRP tube column. The constitutive model for UHPC under passive constraint is developed, in which the yield criterion, hardening/softening law, plastic flow rule, and damage evolution law are determined based on the experimental results of UHPC under multiaxial loading conditions. Furthermore, a solid element model of FRP tube with definable layer information is utilized to simulate the behavior of FRP tubes under complex stress states. The proposed finite element model is implemented in ABAQUS and verified through available experimental results. The results indicate that the proposed model can accurately predict the stress–strain behavior of confined UHPC with varying fiber and coarse aggregate contents, and describe the damage progression of UHPC and FRP tubes. Particularly, the interaction process between FRP and UHPC can be well reflected. The proposed finite element model serves as a paradigm for numerical analysis of UHPC-filled FRP tube elements and provides a reference for simulations of UHPC structures.

Evolutionary Development of Pulse Technologiesin the Production of Rocket Large Parts

An analytical review of research since the 50s of the XXth century is presented, related to the development of stamping by explosion - a promising method of forming large hard-to-process parts, with the following results is established. The source of the force during explosion stamping is the high explosive charge. It is an important factor of criticalities during plastic deformation of a titanium alloy workpiece. There can be many reasons of their origin, and they are taken into account by researchers, but separately. At the same time, the process of force generation is quite complex, especially in the aquatic medium of the basin. However, the process of explosion stamping must be controlled under any conditions. Force delivery to the workpiece surface takes place during explosion stamping within water transfer medium in the basin. Compared with the air medium, the power of this effect increases significantly due to more complete use of the water energy capabilities. Most researchers agreed that the force effect, consisting of a shock wave, motion of a hydraulic flow and a gas bubble, result in complexity of mathematical modeling of the process of its displacement. Mechanical and geometric characteristics of the workpiece affect quality of the part made by explosion stamping. It is determined by the material ability to be plastically deformed and has the effect in strength, accuracy of geometric and angular dimensions, as well as surface condition of the part, the absence of defects, fractures and corrugations. At the same time, a unified quality assessment of the workpiece and part has not been established yet. The multiparametric process of plastic deformation during explosion stamping in water deforms not only of the workpiece, but also of the matrix, thus altering the part shape, walls thinning, the appearance of corrugations and flanges due to the complex stress state in various sections of the part. It is noted that the properties revealed during the explosion stamping, leading to change in corresponding parameters and characteristics, collectively determine the system to which systematic approach may be applied. A feature of explosion stamping study is the need for an experiment, the success of which is largely determined by the experience of the researcher. This stage of the explosion stamping evolutionary development is associated with the introduction of computer technologies into the practice of technological processes design. Research is mainly related to the use of object-oriented methods, the development and application of mathematical models that allow automating procedures for determining the parameters of the stamping process mode, followed by modeling individual actions during stamping by explosion. At the same time, it is necessary to evaluate the performance of stamping by explosion both as a whole and individual stages of its implementation.

Theoretical solutions for 2D mode-I crack-tip stress fields in power-law plastic materials based on the stress factor derived from the developed median-energy–density equivalence method

This study presents the energy density equivalence equation, demonstrating that the strain energy density of an arbitrary representative volume element (RVE) under a complex stress state equals to that under a uniaxial stress state when volume change is neglected. Based on the developed median-energy–density equivalence method, the analytical solution for equivalent stress of the RVE at the energy density equivalence point in power-law plastic materials is derived in a new method and the concept of stress factor is proposed. Additionally, novel special functions are introduced to accurately describe the angular distributions of stresses in this study. By combining the stress factor, integral theoretical solutions for mode-I crack tip stress fields in power-law plastic materials under finite plane conditions are proposed. Finally, parameterized studies are conducted on bending and tension specimens under plane-strain and plane-stress conditions. The results of stress distributions and contour lines predicted by the integral theoretical solutions are compared with the finite element analysis and HRR solutions for five mode-I plane specimens, providing verification of the solutions’ applicability.

Deformation stability transition of notched metallic glasses

Systematical experiments, simulations and microscopic characterizations on double edge notched samples manifested a transition from brittle instability to steady plasticity. Effects of ligament length, geometrical notch parameters as well as thickness were studied. It was found that ligament length is essentially the space provider for intersection of shear bands. With a narrow ligament, it is unlikely to form V-shaped double shear bands because of the limited region between notch tips. Meanwhile, the plastic deformation ability is determined by stress triaxiality. With a wider ligament, V-shaped double shear bands become predominant in controlling deformation stability, accompanying with much higher plasticity than previous investigations because of large-regions of shear band entanglements. Such plasticity enhancement is proven to have weak linkage with the restriction of crosshead of machines, and it is the resultant response of notch configuration. Besides, thickness is less influential to global plasticity. On another hand, by means of hydrostatic stress embedded free volume model, shear banding process is simulated by FEM model, by which the shear band evolution patterns in tests could be well understood and explained. The current findings could further enrich the plastic stability mechanism of metallic glasses under complex stress states. As well, those parameters on notch configurations could provide the state-of-the-art parameters used for fabrication of porous metallic glasses.

The Drucker–Prager criterion-based plasticity theory of amorphous alloys under the complex stress states

The constitutive models of materials are pushed to their limits in a wide range of service scenarios, each with a unique stress state, strain rate, and temperature coupling. This paper successfully captured the stress state sensitivity of amorphous alloys using the free volume theory and the Drucker–Prager yield criterion. The varying yield surface and shear band angle as the dilation coefficient changes are well captured by the FEM simulations. The model can also accurately portray the influence of the stress state, as well as the difference of shear-induced dilation between the tension and compression. This model can facilitate the application of amorphous alloys in complicated local stress states at a large scale and structural level, such as in chiral mechanical metamaterials and gear structures.

Analysis of the nuclear loads on Chromium monoblock divertor target for DEMO

The Plasma Facing Components (PFCs) of DEMO divertor play a fundamental role for the heat removal and particle exhaust functions, during fusion plasma. This implies a very harsh operation environment characterized by the combination of complex loading and stress conditions, intense particle bombardment, high heat flux deposition and a significant neutron irradiation. In the framework of the European DEMO divertor project (WPDIV), several target design concepts alternative to the baseline ITER-like technology are under evaluation, such as Chromium block design. It consists of chromium block, tungsten armor tile and copper alloy cooling pipe, and it is very attractive from an activation reduction, waste management and safety point of view. Therefore, the assessment of the most impacting nuclear loads for the PFC design is a pivotal aspect for DEMO divertor R&D program and this study is fully devoted to the comprehension of the spatial distributions of the main nuclear quantities (radiation damage, He-production and nuclear heating density) on the overall divertor targets. Neutronics analyses have been performed with MCNP5 Monte Carlo code using both DEMO MCNP Water Cooled Lithium Lead (WCLL) and Helium Cooled Pebble Bed (HCPB) blanket models, with a fully heterogeneous representation of the divertor cassette and Chromium PFCs geometry. The results of this analysis show that nuclear heating density and radiation damage distributions are higher with WCLL blanket than HCPB, except for He-production which seems not significantly affected by the blanket configuration. For each nuclear quantity, the peak values are achieved in correspondence of the baffle region and especially on the external units of the targets, as expected, being this region the most exposed to irradiation.

A fatigue life prediction method of cement-stabilized aggregates considering the effect of stress state

Stress state is one of the factors leading to the fatigue life prediction discrepancy of cement-stabilized aggregates (CSA) in laboratory and field pavement structures, therefore, a new fatigue criterion and fatigue life prediction method characterizing this effect is needed which was proposed in this study. Experimental fatigue tests with four loading modes, including uniaxial compression (UC), uniaxial tension (UT), indirect tension (IDT), and four-point bending (FPB) were conducted in several stress levels. The results suggest that the semi-log-linear equation is suitable for all four loading modes, however, the fatigue life of CSA in tension and compression at the same stress level or stress ratio greatly differs. Inspired by the yield and failure criteria theories, bulk stress, shear stress, and principal stress were introduced to establish the fatigue criterion, and accordingly to propose a novel fatigue equation based on the semi-log-linear form, which can unify fatigue life prediction at different stress states. Since the new prediction approach is in terms of stress rather than stress ratio, the process of measuring strength at hard-to-get complex stress states is avoided. Through verification, the proposed method exhibits high agreement with the experimental results of CSA from either this study or literature, and it is capable to characterize the fatigue life difference in tensile and compressive states. Besides, the new fatigue equation was demonstrated to apply to the interpolated data from traditional fatigue curves. In accordance with the loading cycles in experimental tests with addition of considering the applicability of the semi-log-linear equation, the proposed fatigue equation of CSA was justifiably effective at the fatigue cycles of 102 to 107.

NONLINEAR REFINEMENT OF THE DEFORMATION MODEL OF ORTHOTROPIC MATERIALS, THE RIGIDITY OF WHICH DEPENDS ON THE TYPE OF STRESS STATE

As a result of numerous experimental and theoretical studies, it has been established that when deforming both traditional and new structural materials, which are polymers, composites and synthetic structures used in construction, mechanical engineering, and power engineering devices, complicated mechanical properties manifest themselves.Most of these materials have an orthotropic structure complicated by the dependence of deformation and strength characteristics on the type of stress state, which can be interpreted as deformation anisotropy. These properties contradict the generally accepted theories of deformation. Therefore, a number of models have been specially developed for such materials over the past 56 years, taking into account the complicated properties of materials. However, all of them have disadvantages and certain contradictions with the fundamental rules for constructing equations of state. The previous works of the authors of the presented studies establish general approaches to the construction of energetically nonlinear deformation models of composite materials with recommendations for calculating their constants based on a wide range of experiments.It turned out that the set of necessary experiments should include experiments on complex stress states, most of which are technically unrealizable. In another work of the authors in 2021, using the tensor space of normalized stresses, the deformation potential was formulated in a quasi-linear form, constructed in the main axes of orthotropy of materials, for determining constants, which is sufficient for the data of the simplest experiments. Along with the obvious advantages of the introduced potential, it has one drawback, which is to replace real nonlinear diagrams with direct rays with minimal error. Despite the unconditional adequacy of the quasi-linear potential, the use of this level of approximations leads to quantitative errors.Therefore, simplified nonlinear equations of state for composite materials are proposed here, the simplest experiments are sufficient to determine the material functions of which. These equations are based on the general laws of mechanics, on the basis of which the constants of material polynomials for a carbon-graphite composite are calculated, taking into account the Drucker constraints.

Ductile failure of Inconel 718 during flow forming process and its numerical investigation

Understanding the fracture mechanisms and predicting failure in forming processes is of great interest to increase formability and numerical methods have been proven effective. Incremental forming processes such as flow forming possess challenges due to material experiencing complex stress states and highly non-linear deformation histories during forming. Although some of the ductile failure criteria integrated into finite element (FE) simulations are found to be in better correspondence with the experimental findings, they mostly lack sufficient accuracy in predicting formability limits for flow forming and spinning processes. In this context, this work is concerned with the analysis and prediction of ductile failure of nickel-based super alloy Inconel 718 (IN718) in the flow forming process through FE analysis. Failure is modeled with three different models, namely Cockcroft–Latham (CL), Johnson–Cook (JC) and modified Mohr–Coulomb (MMC), implemented as a user subroutine in explicit FE solver Abaqus. Tensile tests are conducted with four different specimen geometries in order to identify parameters of the plasticity and damage models. Then, the developed framework is applied to a FE simulation of the flow forming process to predict formability limits and perform process parameter optimization to improve formability. Flow forming tests conducted at three thickness reduction values reveal that the forming limit of the material is at about 50% thickness reduction where radial cracks are observed on the outer surface. It is found that the CL model is able to predict formability limits and crack initiation locations while the MMC and JC models failed in both with significant over prediction of damage. Furthermore, the effect of temperature and process parameters such as the ratio of feed rate to revolution speed and roller axial and radial offsets are further examined with the developed FE frameworks. It has been shown that process parameter optimization requires accurate modeling of ductile damage since the behavior of different models is diverse.