Part Distortion Research Articles

Effect of Phase Transformations on Scanning Strategy in WAAM Fabrication.

Due to its high production rates and low cost as compared to other metal additive manufacturing processes, wire arc additive manufacturing (WAAM) has become an emerging technology in the manufacturing industry. However, the residual stress generation and part distortion hinder its widespread adoption because of the complex thermal build-histories of WAAM parts. One of the ways to alleviate this problem is to consider the effects of scan strategies as it directly influences the thermal history of the built part. Since WAAM itself is an evolved welding process and even though it is evident from welding studies that phase transformations directly affect the residual stresses in welded parts, it remains unclear how the consideration of phase transformations for different scan strategies will affect the residual stresses and distortions in the WAAMed parts. A FEM study has been performed to elucidate the effects of phase transformations on residual stresses and the distortion for different deposition patterns. The current findings highlight that for the fabrication of low-carbon martensitic steels: The consideration of phase transformations for line-type discontinuous patterns (alternate and raster) do not significantly affect the residual stresses. Consideration of phase transformations significantly affects residual stresses for continuous patterns (zigzag, in–out and out–in). To accurately simulate complex patterns, phase transformations should be considered because the patterns directly influence the temperature history of the built part and will thus affect the phase transformations, the residual stresses and the warpage. During the fabrication of WAAM parts, whenever possible, discontinuous line scanning patterns should be considered as they provide the part with uniform residual stress and distortion. The alternate line pattern has been found to be the most consistent overall pattern.

Efficient distortion predictions of high-performance steel alloy parts fabricated by pragmatic deposition strategies in laser melting deposition

For the prediction of residual distortions of high-performance steel alloy parts induced by laser melting deposition (LMD), two efficient simulation methods are developed, which are the improved thermal-mechanical coupled method and the multiscale method. In the improved thermal-mechanical coupled method, the detailed loading process of the moving laser heat source is omitted, and the deposited coarse blocks are used to divide the LMD parts, which can improve the efficiency of mechanism exploration for the LMD process. Based on the eight-layer line deposition model, the length range of the deposited coarse blocks that can improve the computational efficiency under the premise of accuracy is explored, which is 5–8 mm. The distortion of the substrate after printing two-layer multipath part by pragmatic deposition strategies is accurately predicted by this method, which is consistent with the experimental measurement. The deviation between the predicted maximum distortion and the actual value is only 0.8%. Furthermore, a multiscale method based on the inherent strain method is also adopted. The two simulation methods are used to predict the distortion of the substrate after depositing pragmatic square frame structure. The deviations of the maximum distortion predicted by the improved thermal-mechanical coupled method and the multiscale method are 5.2% and 4.3%, respectively. The time-consuming of the multiscale method is only 2.8% of the former. For the direct prediction of distortion results of large-sized LMD parts in engineering, the advantages of the multiscale method are significant.

Residual stress, distortion, and porosity analysis of LED heat sink printed by SLM process using machine learning

In recent years, Light-emitting diodes (LEDs) are dominating the traditional lighting system. Besides mercury-free, they have small size, good break resistance and long life. Although LEDs are cool to touch, they generate a lot of unnecessary heat inside the gadgets. It is important to remove the heat using efficient thermal management component such as heat sink. Instead of using a conventional manufacturing process, selective laser melting (SLM) process is used to manufacture the heat sink. The quick solidification and various thermal regimes of the material during the SLM process lead to the development of residual stresses that cause the part distortion and harm the mechanical properties of the component. The objective of the current study is to find the optimum value of laser power, scanning speed, and hatch spacing to bring down the residual stress and distortion in the SLM process to an acceptable range. Residual stress and distortion values of the heat sink are simulated using MSC Simufact additive and ANSYS Additive software. The conflicting nature between residual stress and porosity was observed. Hence, grey relation analysis was used to convert residual stress & porosity into a single objective. Optimum process parameters obtained were, laser power 80 (W), scanning speed 950 (mm s−1), and hatch spacing of 70 The values of residual stress and porosity at optimum parameters were found to be 385.58 MPa and 12.21%. Multiple regressions algorithm of machine learning was used to form a relationship between residual stresses and porosity. It was also observed that the magnitude of residual stress and distortion were low at lower energy densities and high at higher energy densities and the residual stress and porosities were high in the z-direction.

Numerical simulation and experimental measurement of pressureless sintering of stainless steel part printed by Binder Jetting Additive Manufacturing

Binder Jetting-Metal Additive Manufacturing (BJ-MAM) is a powder bed-based additive manufacturing technology which deposits liquid binder droplets to join powder particles to form complex shaped structures (i.e., green parts). As the printing process is done around room temperature, BJ-MAM is largely immune to the distortion and cracking issues that can be prevalent in melting based powder bed processes. However, a main issue for BJ-MAM is the part shrinkage and distortion during high-temperature sintering. The densification and deformation behaviors during pressureless sintering of green parts printed by BJ-MAM were studied in this paper. Experimentally, cantilever- and bridge-shaped coupons with varying beam lengths were printed using 316L stainless steel powder; these coupons produced different extents of deformation after sintering. Based on the existing modeling approaches in the powder metallurgy literature, a finite element model was developed incorporating an elastic-viscoplastic constitutive equation for computing both uniaxial equivalent creep strain and volumetric swelling strain. Two methods, a viscosity based and a power-law creep based, were further evaluated for calculating the uniaxial equivalent creep strain. Material property data used in the constitutive equation such as viscosity and creep parameters were collected from the literature, critically reviewed, and then inputted into the model. Other salient features of the model included thermal-mechanical property data that were dependent on both relative density and temperature as well as frictional contact between the part surface and the furnace wall under gravitational load. The calculated quantities such as shrinkage, final relative density, and deformed shapes were compared with the respective experimental data across different part geometries.

Coupling between inherent and machining-induced residual stresses in aluminum components

This work investigates the coupling of inherent residual stress (IRS) and machining-induced residual stress (MIRS) on the final-state of residual stress (FRS) and distortion when high-speed machining (HSM) high aspect-ratio aluminum components. Motivation for this work stems from the simplifications in related numerical investigations that give rise to two limitations: First, the mapping of incompatible, incomplete, and/or spatially scarce IRS profiles generates unrealistic distortions and incorrect stress fields during static equilibration. Second, the simulation of machining via element deletion, inactive elements approach, or Boolean subtraction (removal) of material either ignores thermal and MIRS effects, or implements them based on simplified analytical/empirical models. Such practices therefore prevent a thorough understanding of how IRS and MIRS are coupled. Accordingly, two wrought aluminum 7050 blocks having different IRS profiles (based on stress relief) are considered in this work. An iterative stress reconstruction algorithm is implemented to numerically model a spatially-complete and fully-compatible IRS field in each aluminum block using limited data from slitting measurements documented in the literature. A 2D orthogonal cutting model is used to validate the material and damage models employed, as well as to elucidate the influences of IRS and MIRS on FRS. A 3D end milling model, which adopts the validated material and damage definitions, is then applied with different tool paths to reveal the coupled effects of IRS and MIRS on the distortion when HSM a C-channel featuring high aspect-ratio walls. The results reveal that the interaction between IRS and MIRS is nonlinear in nature, thus contrasting assumptions allowing for their superposition, as are widely reported and adopted in the literature. The results also show that the nonlinear coupling between IRS and MIRS varies according to both the component and location of stress within the machined part. Moreover, the findings reveal that the final part distortion is significantly influenced by the nonlinear coupling, as well as the specific machine tool path implemented.

A computationally efficient thermo-mechanical model for wire arc additive manufacturing

Residual stresses and distortions are major obstacles against the more widespread application of wire arc additive manufacturing. Since the steep temperature gradients due to a moving localised heat source are inevitable in this process, accurate prediction of the thermally induced residual stresses and distortions is of paramount importance. In the present study, a computationally efficient thermo-mechanical model based on a semi-analytical thermal approach incorporating Goldak heat sources is developed for the process modelling of wire arc additive manufacturing. The semi-analytical thermal model makes use of the superposition principle, and thereby decomposes the temperature field into an analytical temperature field to account for the heat sources in a semi-infinite space and a complementary temperature field to account for the boundary conditions. Since the steep temperature gradients are captured by the analytical solution, a coarse spatial discretisation can be used for the numerical solution of the complementary Tˆ field. Thermal evolution is coupled to an elasto-plastic mechanical boundary value problem that computes the thermal stresses and distortions. The accuracy of the proposed model is evaluated extensively by comparing the thermal and mechanical predictions with the corresponding experimental measurements as well as the simulation results obtained by a non-linear transient model from the literature. A thin wall structure with a length of 500 mm and consisting of 4 layers is modelled. The peak normal stress along the deposition direction can be predicted with less than 10% error. Furthermore, the simulations show that the part distortions are very sensitive to the boundary conditions.

Effect of path strategy on residual stress and distortion in laser and cold metal transfer hybrid additive manufacturing

Laser and cold metal transfer (laser-CMT) hybrid additive manufacturing is a novel process that allows the manufacturing of parts with high deposition rates. Residual stress and distortion caused by high heat input hinder the widespread use of this technology in producing large-scale components. This paper studies the effect of the path strategy on residual stress and distortion in laser-CMT hybrid additive manufacturing. Three path strategies viz. same direction motion (SDM), reciprocating motion (RM), and segmental reciprocating motion (SRM) are chosen. A finite element model is built to predict the residual stress and distortion of the thin-walled part with arc and line features. The adequacy of the model is proven by validation experiments. The thermal cycles are obtained by infrared thermography, the residual stress on the beads is measured by X-ray diffraction, and the distortions of the substrate are scanned by the structure light vision sensor. The temperature gradient, residual stress, and distortion of the samples deposited in different path strategies are analyzed using the validated model. The distortion of the substrate in depositing process by the SRM path strategy is smaller than that of the other path strategies. Finally, a manufacturing case for a commercial aircraft load-carrying frame demonstrates that industries can adopt Finite element (FE) analysis as a tool to optimize the path strategy for laser-CMT hybrid additive manufacturing.

Finite element analysis of residual stress and warpage in a 3D printed semi-crystalline polymer: Effect of ambient temperature and nozzle speed

The printing conditions in Fused Deposition Modelling (FDM) affect the amount of induced residual stresses within the printed part and its dimensional accuracy. Among the thermoplastic feedstock for FDM, semi-crystalline polymers are more prone to part distortion due to crystallisation. Therefore, this study aims to numerically investigate the behaviour of semi-crystalline polymer under various FDM printing conditions (namely print speed and ambient temperature) and the resultant residual stress and warpage in the printed parts. For this, the coefficient of thermal expansion (CTE) and the thermo-mechanical properties of the polymer under study (polypropylene), and the crystallisation kinetics are coupled with the evolving temperature and time during printing. The values of residual stress and warpage are calculated and compared for the bottom and top layers of the samples. From the results, it was observed that increasing the nozzle speed from 30 mm/s to 60 mm/s resulted in the bottom and top layers exhibiting a 15% and 13% decrease in residual stress, respectively. Similarly, a drop in warpage (~30%) was observed for both layers. The reduction in residual stress and warpage with increased printing speed is attributed to the improved heat transfer between the deposited roads and the reduced cooling rate. Increasing the ambient temperature from 25 °C to 75 °C resulted in a 2% and 3% decrease in residual stress in the bottom and top layers, respectively. In terms of warpage, an insignificant increase (~1%) was observed in both top and bottom layers. This is explained by the counter effects of reduced thermal gradients (i.e., lower cooling rate) and increased crystallisation on the overall amount of residual stress and warpage. 3D scanning of experimentally printed samples was used for verification of the simulation results, and good agreement between these is reported.

Fakes about Coronavirus: Communicational Technologies for Constructing False Messages

Introduction. Interest in the problem of false (fake) news has increased significantly in the situation of the coronavirus pandemic, when the flow of false information considered as an obstacle to the implementation of measures to combat the pandemic itself and its consequences. The authors aim to study the existing works devoted to the analysis of the construction and recognition of false news about COVID-19, paying special attention to the procedures of fact-checking-process of verifying the accuracy of the information contained in the message. The novelty of the author’s approach lies in the use of a content analysis of the fact-checking resource to identify communication technologies for constructing fake news about the coronavirus.Methodology and sources. As a theoretical framework, authors used the information model of communication by Claude Shannon, structuring communication as a process of information transmission and fixing the possibility of noise (distortion) in various parts of this process. The empirical basis of the study was a fact-checking resource that specializes in identifying fakes about the coronavirus (47 units of analysis were considered for the period from March to May 2020).Results and discussion. In the result of the research, specific communication technologies of purposeful construction of false news were identified – distortions in the communication channel, distortions in the message code (content), distortions in the message source. We also identified the types of distortions associated with the content of communication – based on the creation of false content, recoding information (giving it a new interpretation), editing the original. Different frequency of application of these technologies for a given volume of analysis units were been recorded, as well a s the predominance of the technology of distortion of the communication channel.Conclusion. The authors draw a conclusion about the importance and relevance of the topic of constructing fake news in the situation of the ongoing COVID -19 pandemic, demonstrate the productivity of using fact-checking resources to identify various communicative technologies for constructing false messages, which creates new prospects for recognizing and countering them.

NOISE IMMUNITY IN DATA COMPRESSION INFORMATION AND MEASUREMENT SYSTEMS

When processing huge data streams in information systems, individual measurements or whole groups of measurements can be distorted or lost due to various reasons. Recovery of compressed data during transmission on communication channels is accompanied by errors related to distortion of information and service parts of messages due to presence of interference in transmission channel. To these errors are added errors caused by quantization of the transmitted implementations by level and time sampling. Research on methods of increasing noise immunity both during transmission and during recovery of measured data is an urgent task in the design of information and measurement systems. The article considers non-parametric methods of estimating probabilistic characteristics of random processes. A distinctive feature of non-parametric methods is the ranking of data measured at the observation interval. It is shown that ranking of data on transmitting side of information-measuring system enables correction of errors and failures based on strict monotony of ranked number of codes. Also, the error of recovery of continuous implementations taking into account distortions of compressed data in the communication channel was investigated. The obtained results indicate that the use of complex compression algorithms is impractical, since the difference in the error in the restoration of non-stationary messages between the simplest algorithm and the rather difficult one becomes negligible. The article presents the results of estimating recovery errors for various data compression methods.

Dual-frequency ultrasonic cleaning with diluted phosphoric acid solution for removing oxide scale of uncoated steel sheets in hot stamping

Dual-frequency ultrasonic cleaning with a diluted phosphoric acid solution was developed to remove oxide scales on surfaces of hot-stamped parts from uncoated steel sheets, and conventional shot blasting processes are omitted. The removal of the oxide scale by ultrasonic cleaning is accelerated by the phosphoric acid solution and the dual frequency. The removing time for the phosphoric acid solution was shorter than that for a hydrochloric acid solution, and rust appearing for leaving after cleaning was prevented by generating an iron phosphate layer. In dual-frequency ultrasonic cleaning with the diluted phosphoric acid solution, the oxide scale was dissolved, and then the oxide scales were exfoliated from the thin scale and high-pressure portions. The removing time decreased with decreasing pH and oxide scale thickness and with increasing solution temperature. The surface roughness and distortion of an ultrasonic-cleaned hot-stamped part were smaller than those for shot blasting, and the weldability and paintability were similar. The oxide scale of a hot-stamped part having a nonuniform distribution of oxide scale thickness was successfully removed by dual-frequency ultrasonic cleaning with the diluted phosphoric acid solution.

Feedback Control of Melt Pool Area in Selective Laser Melting Additive Manufacturing Process

Selective laser melting (SLM), a metal powder fusion additive manufacturing process, has the potential to manufacture complex components for aerospace and biomedical implants. Large-scale adaptation of these technologies is hampered due to the presence of defects such as porosity and part distortion. Nonuniform melt pool size is a major cause of these defects. The melt pool size changes due to heat from the previous powder bed tracks. In this work, the effect of heat sourced from neighbouring tracks was modelled and feedback control was designed. The objective of control is to regulate the melt pool cross-sectional area rejecting the effect of heat from neighbouring tracks within a layer of the powder bed. The SLM process’s thermal model was developed using the energy balance of lumped melt pool volume. The disturbing heat from neighbouring tracks was modelled as the initial temperature of the melt pool. Combining the thermal model with disturbance model resulted in a nonlinear model describing melt pool evolution. The PID, a classical feedback control approach, was used to minimize the effect of intertrack disturbance on the melt pool area. The controller was tuned for the desired melt pool area in a known environment. Simulation results revealed that the proposed controller regulated the desired melt pool area during the scan of multiple tracks of a powder layer within 16 milliseconds and within a length of 0.04 mm reducing laser power by 10% approximately in five tracks. This reduced the chance of pore formation. Hence, it enhances the quality of components manufactured using the SLM process, reducing defects.

Method for Rapid Modeling of Distortion in Laser Powder Bed Fusion Metal Additive Manufacturing Parts

The simulation and modeling of part-level distortion and residual stress in diverse metal additive manufacturing (AM) geometries has great potential to enable the rapid adoption of this technology in engineering design. Moreover, the use of additive manufacturing component libraries (CLs) offer a computationally efficient means of quantifying these part-level defects resultant from AM processing. We report on how the individual simulations of simple shapes, potential entries in a CL, can be superimposed to provide an indication of distortion and residual stresses in complex geometries. Laser powder bed fusion AM was used to construct test geometries of varied shapes and their combinations in the form of CLs in an effort to characterize location-dependent and feature-dependent distortion distributions. Blue light scanning was used to experimentally measure 3D distortions in order to investigate the interaction between the component shapes and local boundary conditions. Overall, part-level distortions were highly dependent on test component geometry, local boundary conditions, and shape combination. Commercial finite element software was used to verify experimental trends and to make predictions of distortion. The use of CLs resulted in over 20 times savings in computational cost while reproducing overall trends in distortion for test geometry assemblies. Therefore, it is anticipated that the use of CLs for L-PBF AM geometries has demonstrated potential to facilitate efficient simulations of full component AM assemblies, thereby reducing the need for costly trial-and-error-type experimental analysis.

Topology Optimization for additive manufacturing with distortion constraints

An important cause of failure in powder bed additive manufacturing is the distortion of the part due to thermal shrinkage during printing and the relaxation of residual stresses after its release from the base plate. In this paper, Additive Manufacturing simulations are coupled with Topology Optimization in order to generate designs that are not susceptible to failure associated with distortion. Two possible causes of failure are accounted for: recoater collision and global distortion of the product. Both are considered by simulation of the build process and defined as constraints in the context of a Solid Isotropic Material with Penalization method based topological optimization. The adjoint method is used to derive the sensitivities of the additive manufacturing constraints. The method is demonstrated with the 2D and 3D optimization of a bracket. Next to global topological changes, the obtained designs show features that are aimed at facilitating the printing process. These features resemble supports that are routinely applied to powder bed additive manufacturing. The formulated constraints were found to prevent excessive part distortion and associated build failures in all cases, against a modest increase in the compliance of the bracket.

Mitigation of heat treatment distortion of AA 7075 aluminum alloy by deep cryogenic processing using the Navy C-ring test

Abstract Heat treatment is a promising approach to advance the mechanical properties of AA 7075 aluminum alloy for aerospace structural applications. Quenching is commonly performed after solutionizing of AA 7075 aluminum alloy to impart supersaturated solid solution condition. It involves rapid cooling of the previously solutionized part to room temperature with water as a quenching medium. It leads to severe distortion of the structural part and deteriorates its surface integrity due to the high thermal residual stresses. This paper reports the distortion behavior of heat-treated AA 7075 aluminum alloy by implementing the standard Navy C-ring test. For precise measurements, the coordinate measuring machine (CMM) was used. Deep cryogenic treatment (DCT) was executed after conventional heat treatment (CHT) to reduce the tensile residual stresses and mitigate the distortion potential of AA 7075 aluminum alloy. Results showed significant improvement in surface finish and hardness of deep cryogenically treated AA 7075 aluminum alloy. It is attributed to the precipitation of fine spherical second phase particles distributed uniformly in the matrix. The distortion potential of heat-treated AA 7075 aluminum alloy is minimized by 30.7 % by deep cryogenic processing. It is correlated to the counterbalancing of tensile residual stresses in the heat treated part by compressive residual stresses ensued by deep cryogenic quenching.

A numerical study of the effect of the thickness parameter on machining distortion for aluminum alloy plates

The deformation produced after the machining of a structural component is known as part distortion. This phenomenon is a consequence of the inherent residual stresses that exist in raw materials. In this study, such phenomenon is numerically investigated in simple plate elements by considering their thicknesses and their corresponding contribution to part distortion. A total number of eleven flat plates were analyzed using a numerical part distortion procedure for finite element models that also considered their machining positions. The results of this study show that part distortion has more impact on slender plates because these present higher loads than thicker plates in which the residual stresses self-balance throughout their section. Consequently, the part distortion phenomena in simple structural flat plates are related the plate thickness, their machining position, and geometrical parameters.

Comparison of the microstructure, mechanical properties and distortion of stainless steel 316 L fabricated by micro and conventional laser powder bed fusion

Micro laser powder bed fusion (μLPBF) technology offers great benefits to industries as it enables fabrication of complicated metallic components with greater accuracy and minimum feature size as small as 50 µm. Employing finer laser beam and smaller metal powder in μLPBF leads to many variations from the conventional LPBF (cLPBF) in terms of microstructure, mechanical properties and distortion, which have not yet been well understood. This work provides a comparative study of the μLPBF and cLPBF of the well-known material, stainless steel 316 L based on the surface quality, crystal structure, solidification microstructure, tensile properties and distortion of as-printed parts, and their sensitivities to μLPBF process parameters are also studied. Results show that lower surface roughness (Ra= 3.4 µm for top surfaces) is obtained after μLPBF. Stronger < 110 > texture along building direction is developed in the μLPBFed samples, accompanied with smaller grain size, higher density of low-angle grain boundary (LAGB) and geometrically necessary dislocation (GND). μLPBF creates a cellular microstructure with smaller cell size and cell wall thickness compared with cLPBF. The yield strength of μLPBFed samples is marginally lower than cLPBFed ones, which is dominated by the difference of compositional microsegregation in the cellular structures. Both cLPBFed and μLPBFed samples show a strong anisotropy in terms of yield strength, ductility and deformation behavior. The distortion measurement of the printed cantilever design suggests a lower level of macroscopic residual stresses in the μLPBFed samples due to the smaller molten pool and more thermal cycles. Moreover, the microstructure, mechanical properties and distortion of μLPBFed samples remain at the same level with variation of laser power and scanning speed. Overall, better surface finish, finer microstructure, more desirable mechanical properties and smaller part distortion can be obtained by μLPBF.

New insights into nonlinear optical effects in fullerene solutions—a detailed analysis of self-diffraction of continuous wave laser radiation

Spatial self-phase modulation (SSPM), i.e. the formation, temporal evolution and subsequent distortion of self-diffraction ring patterns, generated by transmitting a continuous wave 532 nm laser beam through solutions containing C60 or C70 has been investigated. The nonlinear optical response regarding SSPM of such systems was studied, to our knowledge for the first time, in dependence of various solvents, different sample temperatures and viscosities. The SSPM patterns consisted of a number of concentric rings, generated due to induced refractive index changes and start with a central spot, expanding into a series of concentric rings. The number of rings increases steadily and the ring pattern becomes larger with time until a maximum is reached. Thereafter, thermal convection leads to a distortion of the upper part of the ring system, while the lower part keeps its shape. The dependence of temporal and spatial evolution of self-diffraction ring pattern on different sample parameters and not only the functional material itself, leading to our conclusion that thermal effects are responsible for the observed SSPM. For further substantiation, measurements of C60 in toluene at a wavelength of 1070 nm have been carried out. At this wavelength no absorption occurs and no SSPM patterns were observed. Knowing that for ultashort pulses no significant thermal effects take place, we performed additional measurements at a pulse length of 8 ps and a wavelength of 527 nm. Also in this case no SSPM patterns were generated. In order to gain a deeper understanding of the involved physical processes, we developed a thermal blooming simulation: Thermally-induced refractive index changes and convection caused by locally heating of the solution by the laser beam were taken into account, any other nonlinear phenomena were left aside. A laser beam propagating through an absorbing solution generates similar ring structures under these conditions, what is in fully agreement with our experimental results. Additionally, as a practical application of SSPM a laser protection device is presented.

Application of C-Ring Specimen for Controlling the Distortion of Parts During Quenching

Application of C-Ring Specimen for Controlling the Distortion of Parts During Quenching

Design for the reduction of volume shrinkage-induced distortion in digital light processing 3D printing

Due to its high printing resolution and fast printing speed, digital light processing (DLP) has become one of the most widely used additive manufacturing technologies. In a typical DLP printing, resin is photocured from liquid into solid accompanied by a large volume shrinkage, which often leads to shape distortion of printed structures. In this study, we investigated the volume shrinkage-induced distortion of DLP-printed parts by conducting experiments, theoretical modeling, and finite element analysis (FEA) simulations. Material property evolution coupled with volume shrinkage during photocuring was first modeled constitutively. The constitutive theory was then implemented into FEA simulations of the layer-by-layer DLP printing process to study the development of shape distortion due to volume shrinkage during printing. Experiments validated the efficiency of the proposed FEA simulations. FEA was further applied to help predict the shape distortion in printed microfluidic channels and overhanging structures where printing parameters for compensating for distortion can be designed based on FEA.