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The diagenetic evolution is an important controlling factor of shale gas reservoir. In this study, based on field outcrop and drilling core data, analytical techniques including X-ray diffraction (XRD), field emission scanning electron microscope combined with a focused ion beam (FIB-FESEM), and energy dispersive spectroscopy (EDS) analysis were performed to determine diagenetic evolution of the Longmaxi Formation shale , and reveal effect of diagenetic evolution on the shale gas exploration and development in the Sichuan Basin, Southwest China. The diagenetic evolution can be divided into eodiagenesis, mesodiagenesis, and teleodiagenesis. The eodiagenesis and mesodiagenesis were subdivided into two and three evolution stages respectively both in Basin margin and center. Absorbed capacity and artificial fracturing effect of the Longmaxi Formation shale gas was related to mineral composition, which was influenced by the sediment characteristics and diagenetic evolution. Diagenetic system in the Basin margin was more open than that in Basin center due to different structural burial history. The more open diagenetic system consisting of more micro-fractures and soluble constitute (e.g. feldspar) was in favour for formation and preservation of secondary dissolved pores and organic pores in the Basin margin. The relatively closed diagenetic system with stronger compaction resulted in deformation of pore space in the central Basin due to different burial history and diagenetic evolution.

Microfractures are key for migrating and aggregating hydrocarbon source rocks and fracturing oil-gas exploitation in tight reservoirs. In this study, rock samples from the Lucaogou Formation tight reservoirs in Xinjiang, China, were studied using multidisciplinary techniques to investigate the genetic types and main control factors of microfractures. Results indicated that the Lucaogou Formation mainly developed diagenetic microfractures followed by tectonic microfractures, with slight formations of granular microfractures. These observations were used to clarify the relationship between the development of microfractures and the pore fluid content, lithology, mineral composition, and stratum thickness. A higher pore fluid content corresponded to a lower compressive strength of the rocks and a larger ring count, resulting in a higher probability of failure and microfracture formation. Tight reservoirs containing more quartz and carbonate minerals were found to develop more microfractures. Quartz grains showed fractures at the margins under stress, which increased the pore permeability of rocks. Carbonate minerals tended to form microfractures owing to corrosion. Microfracture formation mechanisms differed depending on lithology, and microfractures were found to develop most in dolomite and dolomitic siltstones and least in mudstone. Muddy rocks developed fewer tectonic fractures because they can easily absorb stress and undergo plastic deformation. Within a certain stratum thickness range, the average single-well fracture space and stratum thickness showed positive correlations. Moreover, the fracture space increased and the fracture density decreased as the stratum thickness increased. When the stratum thickness was less than 2.5 m, the fracture space increased linearly with the stratum thickness, and when the stratum thickness was greater than 2.5 m, the fracture space remained constant. This study will provide an essential scientific basis for enhancing tight oil recovery.

The dolostone reservoir of the Middle Permian Maokou Formation in Eastern Sichuan has good prospects for oil and gas exploration. Study of dolomitizing genesis of the Maokou Formation is essential for predicting the distribution of the dolostone reservoir. Petrography, in situ geochemistry, Sr-Mg isotopes, and fluid inclusions were carried out on samples from the Maokou Formation in Eastern Sichuan in order to discuss the dolomitizing process. Based on mineral and textural characteristics, dolomites were divided into four components: partially clouded dolomite (PCD), mosaic-like dolomite (MLD), cloudy-centered and clear-rimmed dolomite (CACD), and saddle dolomite (SDD). Results indicate that the Maokou Formation in Eastern Sichuan mainly experienced two stages of dolomitization. PCD, MLD, and cloudy-centered dolomite (CCD) were formed during the early dolomitization. They all show turbid crystal planes and bright orange-red CL and have similar trace element contents, 87Sr/86Sr ratios, and rare-earth patterns, indicating that they might be formed in the same fluid. This is a period when dolomitizing fluids mainly migrated along pores or microcracks and replaced protogenetic calcites, which occurred in the shallow burial stage of the Maokou Formation before the Late Permian. Clear-rimmed dolomite (CRD) and SDD were formed in the late stage of dolomitization. They all have clean crystal planes and darkly red CL. CRD of the ERY profile has trace element contents, 87Sr/86Sr ratios, and rare-earth patterns similar to SDD of the HLCH profile and Well TL6, inferring that both may be formed in the same fluid. Combined with high SrO contents and homogenous temperatures of fluid inclusions of CRD and SDD and Mg-isotopic compositions, they were generated by hydrothermal dolomitization. The hydrothermal fluid stage is related to the movement of the Emeishan Large Igneous Province, which was made up of basaltic magmatic fluids mixing with the surface water. The hydrothermal fluid mainly migrated upwards along structural fractures or faults and filled in structural fractures, occurring in the Late Permian to Middle-Late Triassic.

There has been an increased attention on hyperpycnal flows due to its importance in delivering large volumes of sediments into deep-water. The process and products of hyperpycnal flow in tectonically-active margins are still poorly understood, and potentially constitute one of the most important deep-water mechanisms in rift basins. This study integrates core data, well-logging and 3D seismic data to investigate the hyperpycnal flow process and dispersal pattern on the Eocene Dongying rift margin. 17 facies, including 5 conglomerate facies, 9 sand facies and 3 mud facies are identified, interpreted as the product of debris flows, traction currents, turbidity currents, transitional flows and lofting plumes, and suggesting the complex blend in flood-triggered hyperpycnal flow on rift margin. Two different hyperpycnal flow types are identified and a related process model is proposed based on facies sequence, distribution, transport mechanism and flood discharge analysis, including seasonal-flood triggered hyperpycnal flow (SHF) and outburst-flood triggered hyperpycnal flow (OHF). The evolution of the hyperpycnal system suggests two dispersal styles, including proximal sublacustrine fan dominated by OHF and distal sublacustrine fan dominated by SHF, respectively. Climate and tectonic movements are suggested to be the main factors controlling hyperpycnal flow generation and deposition on rift margins. The relatively arid climate enhanced seasonal-flood activity and associated sustained and stable SHF, which further prompt distal sublacustrine fan development during a weak rifting period. On the other hand, the generation of outburst-floods can be attributed to the enhanced fault activity, which corresponds to the periodical tectonic movements in the basin. As a result, proximal sublacustrine fans tend to develop in near-shore topographic lows down-dip of syn-depositional faults due to increased tectonic activities, accommodation and enhanced OHF. A deep-water depositional model is proposed for hyperpycnal systems on rift margins by emphasizing the variety in sedimentary process and dispersal patterns controlled by climate and tectonics forces, which may provide new insights into hyperpycnal flow theories and deep-water exploration in world rift basins.

The ammonia-synthesis industry has become a research hotspot, because its high energy consumption and CO2 emission exacerbate the current resource shortages and environmental pressures. However, the current research on life cycle assessment (LCA) of synthetic ammonia in China is limited. To fill gaps, this study analyzed the environmental performance of mainstream ammonia synthesis in China, i.e., pulverized coal entrained flow gasification (PEF) technology, based on LCA method. Results showed that the potential environmental impact on fossil depletion category was the main contributor to the overall environmental burden, which was primarily from coal mining and coal washing (85.3%). Global warming also had an indispensable impact on the overall environmental burden, and electricity was a dominant contributor with a proportion of 36.3%. Compared with anthracite fixed bed gasification (AFB) technology, PEF technology showed superiority in reducing the environmental burden, especially in the categories of global warming, freshwater ecotoxicity, and water depletion. Ammonia-synthesis routes based on the “green hydrogen” and “blue hydrogen” can greatly reduce carbon emission compared with the “grey hydrogen” route, with reduction ratios of 90.9% and 42.9%, respectively. Results further indicated that “green hydrogen” and “blue hydrogen” routes had huge prospects for environmental optimization in China's synthetic ammonia market. Green mining, underground coal washing technology, and renewable electricity substitution can effectively reduce the environmental burden throughout the entire life cycle of ammonia synthesis.

This study investigates natural tectonic fractures in 22 wells that penetrated the tight oil reservoirs in the middle Permian Lucaogou Formation in the southeastern Junggar Basin, China. Analysis was conducted using conventional image logs of wellbores, acoustic emissions (AEs) data collected from core rock mechanics testing, fluid inclusion analysis, and C–O stable isotopes and Ir element analyses of fracture-filling minerals, in order to constrain the relative timing of fracture development. The geochemical properties of fracture-filling minerals and Kaiser effect points, combined with the regional tectonic analysis, revealed a four-stage fracture development in the tested tight reservoirs. During Stage 1, continuous N–S compression occurred at the end of Late Triassic, producing many NW-trending extensional fractures. Calcite fillings were formed within these fractures at temperatures between 31.7 and 45.0 °C based on fluid inclusion analysis. SW–NE compressive stress was produced in the Middle−Late Jurassic during Stage 2, forming ENE-trending shear fractures. The calcite fillings within these fractures formed at temperatures between 50.1 and 64.6 °C. During Stage 3, intense N–S compression formed NNW-trending shear fractures in the Early Cretaceous, and calcite fillings formed at temperatures between 80.0 and 89.9 °C. Finally, Stage 4 corresponds to nearly N–S compression due to the tectonic activities occurring from Tertiary to nowadays, creating NNW-trending shear fractures; no or minimal partial filling of calcite occurred during this Stage. Based on the relation between the oil generation windows and stages of fracture development, it is proposed that the fractures that developed within the Lucaogou Formation during Stages 2–4 have minimal mineral filling, which is most favorable for oil and gas migration and accumulation.

The shallow-marine turbidite fans in the Upper Miocene Huangliu Formation of the Yinggehai Basin in the northwestern South China Sea (SCS) provide an excellent opportunity to understand their sedimentary processes in a shelf depositional environment. The down-slope gravity flow processes and along-slope bottom-current reworking processes of shallow-marine turbidite fans were interpreted by using seismic, well logging, core, petrographic, geochemical, and petrophysical data. Several depositional elements were identified in the shallow-marine turbidite fans, namely, channel-fill high-density turbidites (HDTs), channel-fill low-density turbidites (LDTs) and associated frontal splays, sand-rich/mud-rich lobe deposits, and bottom-current reworked channel-fill/lobe deposits. Deep U-shaped (or V-shaped) seismic reflections and low root-mean-square (RMS) amplitudes characterize the channel-fill HDTs that consist of massive fine-grained sandstones with mud clasts. The channel-fill LDTs, characterized by V-shaped or worm-shaped reflections, mostly consist of normally graded, laminated and rippled, very fine-grained sandstones. Frontal splays are generally associated with channel-fill LDTs. The sand-rich lobe deposits show continuous high-amplitude sheet-like reflections and consist of HDTs and LDTs, whereas the mud-rich lobe deposits show continuous moderate-amplitude reflections and consist of muddy debrites. The bottom-current reworked sandstones (BCRSs), which comprise well-sorted, fine-grained sandstones with traction-current structures, are usually located in the upper parts of thick sandbodies. The variability of depositional elements from large-scale channel-fill HDTs with strong basal erosion in fan-1 to small-scale channel-fill LDTs in fan-2 is closely linked with sea-level fluctuations that result in variable gravity-flow energy and sediment input. However, the reoccurrence of large-scale channel-fill HDTs in fan-3 at sea-level highstands may possibly be attributed to enhanced sediment input from the source areas. Down-slope flow transformation from turbidity flows into muddy debris flows within an individual channel-lobe complex (CLC) resulted in a dramatic increase in clay content and resultant decreasing reservoir quality from the channel-fill HDTs to the mud-rich lobe deposits, because muddy sediments are incorporated into the precursor turbidity flows and turbulence is suppressed. Additionally, it is suggested that the widely developed traction-current structures and tidal signatures (double mud layers, mud-draped ripples, discrete wavy bedding, internal truncation surface, and convex-up laminae) are the products of reworking by internal waves and -tides. During periods of sea-level highstands, the upper parts of gravity-flow sandstones would undergo bottom-current reworking, thus resulting in the retransportation of muddy fines and the formation of reworked sandstones with traction-current structures and tidal signatures. In this study, a combination of traction-current structures, tidal signatures, vertical sequences showing sharp upper contacts and non-gradational upper contacts, and trace elements is considered to be convincing diagnostic criteria in distinguishing reworked sandstones from gravity-flow sandstones. The representative bottom-current reworked sandstones should be preferable hydrocarbon targets in further exploration because of their better reservoir properties compared with gravity-flow sandstones. This research offers some insight into gravity-flow processes and bottom-current reworking processes in a shallow marine environment.

Deeply buried (3000–5000 m), deltaic sandstones of the Upper Triassic Xujiahe Formation are important tight gas reservoirs in the Sichuan Foreland Basin, China. The diagenesis of these tight sandstones was examined using a variety of petrographic and geochemical techniques, including thin section description, X-ray diffraction (XRD), whole-rock chemical analysis, scanning electron microscopy (SEM), Cathodoluminescence (CL) imaging, electron probe analysis, fluid inclusions and isotopic analysis. These integrated petrographic and geochemical techniques were used to determine the diagenetic history of the sandstones and its impact on the reservoir quality. The tight deltaic sandstones of the T3x2 and T3x4 (second and fourth members of Xujiahe Formation) have undergone a significant and complicated series of diagenetic alterations and changes in geochemical composition. Strong mechanical and chemical compaction together with carbonate cementation destroyed almost all the primary pores and the secondary dissolution pores now dominate the pore space. The T3x4 sandstones experienced a more open diagenetic system at near-surface and eodiagensis resulted in higher porosity than seen in the T3x2 sandstones. Both the T3x2 and T3x4 sandstones experienced closed-system diagenesis during middle-late mesodiagenesis. The early diagenetic dissolution, which mainly occurred in the open geochemical system, produced secondary pores and provided kaolinite and some K+ needed for the subsequent illitization of kaolinite and K-feldspar. The late dissolution of K-feldspar and illitization of K-feldspar in T3x4 sandstones and T3x2 sandstones during the mesodiagenesis, produced some effective secondary pores in the closed geochemical system or in the focused fluid flow zone along fractures. The diagenetic characteristics, size and evolution of (open vs closed) diagenetic system, which were constrained by the depositional environment, deep burial depth and tectonic activity, can be used to predict the reservoir quality ahead of drilling.

The lithofacies characteristics of fine sedimentary rocks affect the hydrocarbon generation capacity and reservoir performance of tight oil and are closely related to the sedimentary environment. On the basis of field outcrops and core observations, combined with logging data, thin section identification, grain size analysis, organic carbon analysis and physical property tests, the fine sedimentary facies of the Chang 7 Member in the Ordos Basin are studied. Nine lithofacies types are identified in the study area, including planar and trough cross-bedding sandstone facies (Spt), massive bedding sandstone facies (Sm), slump deformation fine sandstone facies (Ssd), sand-mud interbedded facies (Sb), rippled siltstones facies (Fr), horizontal bedding mudstone facies (Mh), massive bedding mudstone facies (Mm), horizontal bedding shale facies (S) and tuff facies (T). Lithofacies types Spt, Ssd, Fr are developed in the gentle slope belt in the northeastern study area, which is a delta front-semi-deep lake sedimentary environment and mainly contains underwater distributary channel and estuary dam sedimentary microfacies types. Lithofacies types such as Sm, Sb, Mh and T are developed in the southwestern steep slope zone of the study area, which is a channel-type gravity flow sedimentary environment, and sedimentary microfacies types such as near-source channels, far-source channels and leading-edge dolomites are developed. In the vertical direction, during the Chang 73 sedimentation period, the lake surface area and water depth reached their maxima, and S and Mh lithofacies developed, which were conducive to the formation of high-quality hydrocarbon source rocks for tight oil. During the Chang 72-Chang 71 sedimentation period, the lake basin shrank, and the reducibility of the water body weakened. The delta front sand body composed of Spt lithofacies in the northeast and the sandy clastic flow sand body composed of Sm in the southwest constitute the main tight oil reservoirs. High-quality hydrocarbon-generating lithofacies and favourable reservoir lithofacies are spatially superposed and developed, forming two source-reservoir combinations in the Chang 7 tight oil source-reservoir formation and near source-reservoir formation.

Fluid field can have significant effects on corrosion rates of steels. The objective of this paper is to investigate erosion-corrosion mechanisms of J55 steel and the effects of local hydrodynamic factors, in particular, the fluid flow velocity on J55 steel’s service life. A new experimental setup was developed to specifically simulate the actual hydrodynamic conditions of Huanghe (Yellow) River valley. Computational fluid dynamics (CFD) model was adopted to characterize the hydrodynamic factors, such as the flow rate, the turbulence kinetic energy and the shear stress, and their effects on the corrosion behavior of J55 steel. Corrosion morphology was analyzed. Results show that the erosion rate increased with the flow rate and the resulting corrosion pit became smaller and deeper. Through the research results of this paper, it could provide some technical supports for the scientific and rational exploitation of brine.

Geothermal energy is considerably encouraged by governments because it offers a low-carbon renewable option to satisfy the long-term heat demand. However, to date research on systematic and scientific evaluations of the environmental benefits of geothermal heating is limited. Therefore, compared with the traditional coal-fired heating system, the cleanliness of geothermal heating is examined by employing the life cycle assessment approach in this study. Results show that the environmental impacts of geothermal heating are considerably less than those of coal-fired heating, and geothermal heating with water reinjection is the most ideal scenario. Environmental benefits linearly increase with the injection rate growth of geothermal water. Compared with coal-fired heating for per GJ of heat generation, geothermal heating can lead to 77%, 76%, and 78% reductions in terms of particulate formation, carbon emission, and fossil energy depletion, respectively. The electricity consumption process is the main contributor to the overall environmental burden of geothermal heating. Instead of coal power for geothermal heating, the actual hybrid electricity of China in 2017 (i.e., 64.7% coal power, 18.6% hydropower, 4.7% wind power, 1.8% solar energy) can lead to 27%, 33%, and 27% reductions in fossil depletion, carbon emission, and particulate formation for per GJ of heat production, respectively. These findings not only indicate the feasibility of using geothermal resources to address carbon emissions, energy crisis, and air quality issues, but also demonstrate benefits for human health and ecosystem quality. Furthermore, the results highlight the importance of generating electricity with clean energy in geothermal heating. Thus, generating electricity with clean energy instead of coal is necessary to further reduce the environmental impact of geothermal heating.

Two oolites of the Lower Triassic Feixianguan Formation on the margins of the Kaijiang-Liangping (K-L) Trough in the NE Sichuan Basin were deposited in the upper parts of similar shallowing-upward sequences, and are capped by a subaerial exposure surface. However, they have contrasting diagenetic histories and reservoir qualities: the sour oolitic dolostone reservoirs on the eastern side of the K-L Trough have significantly higher porosities than the sweet oolitic limestone reservoirs on the western side. A petrologic and geochemical comparison of the two oolites was carried out so as to investigate the role of diagenetic processes on the co-evolution of oolite structure and pore network. On both sides of the K-L Trough, eogenetic meteoric digenesis led to an inversion of texture with ooid dissolution and interparticle cementation in the oolite layers close to the exposure surface. The layers relatively far from the exposure surface mostly underwent recrystallization in association with connate seawater, resulting in neomorphic fabrics in the ooid cortices and less interparticle calcite cement. During the subsequent dolomitization, the early-formed oolite structure were mostly inherited by the dolostones on the eastern side, with fabric-retentive textures in the layers close to the exposure surface and fabric-destructive textures in the layers far from the exposure surface. During deeper burial the oolitic limestones were subjected to extensive calcite cementation and porosity loss, whereas the dolostones generally retained more porosity and have better connectivity of the micropore network. The higher porosity of the dolostones is ascribed to lesser chemical compaction and associated cement precipitation, rather than the creation of new pores. Porosity enhancement is closely dependent on the absence of the calcite cement related to pressure solution. The heterogeneity of the dolostone fabrics and the porosity was further enhanced by the subsequent recrystallization and the dissolution-reprecipitation process induced by thermochemical sulfate reduction, during which small amounts of net porosity are calculated to have been created. The oolitic limestones are the best reservoirs close to the exposure surface, whereas the most porous dolostones with the highest degree of fabric destruction are commonly some distance from the exposure surface. These results provide some insights into the diagenetic controls on oolite structure and porosity, and have implications for predicting the porosity of deeply-buried oolitic reservoirs, so have global theoretical and practical significance.

Previous studies have reported faunal changeover and carbon isotope excursions through the Wuchiapingian–Changhsingian (W C) transition, a geologically significant period of time that bridged two major extinction events: the end-Permian and Guadalupian–Lopingian boundary mass extinctions. However, the causes of the carbon isotope excursion across the W C interval remain poorly understood. This study presents sedimentological and geochemical data from three well-exposed sections in the lower Yangtze region, South China. A strong negative carbon isotope excursion in organic matter is recorded across the W C interval and correlates well with other sections in South China. Sedimentology and elemental geochemistry indicate that the lower Yangtze region experienced a distinct regional deepening during the W C transition inducing bottom water redox changes increased primary productivity. Possible causes of the negative carbon isotope excursion at the W C boundary include selective preservation of organic matter during early diagenesis under anoxic/euxinic conditions and changes in terrigenous organic matter input. Both of these factors were controlled by regional relative sea-level rise triggered by contemporaneous tectonic movements.

This paper proposes an improved genetic algorithm to enhance the search efficiency and robustness of robot path planning. Its three main contributions are: 1)initialization: free grids are divided into multiple sets according to the main diagonal direction, and all feasible subpaths in each set are found. From a given starting point, feasible subpaths are randomly selected in each set and orderly connected to reach the end point. This guarantees that each initial path is feasible. 2)mutation: a new mutation operator is proposed to ensure the generated paths are feasible. 3)simplification: a simplification operator is proposed to shorten the path while maintaining its feasibility. Experimental results demonstrate the speed and performance of the proposed algorithm.

Order acceptance and scheduling problem is considered in a flow shop where the objective is to decide on the orders to accept and schedule the accepted orders so as to maximize total net revenue. An effective shuffled frog-leaping algorithm (SFLA) is proposed, in which population is divided into memeplexes using tournament selection and the search process within each memeplex is done on the best solution of the memeplex. We assess the performance of SFLA using an extensive set of instances. The experimental results show that SFLA can provide the promising results on the considered problems.

In this study dual-resource constrained job shop scheduling problem with multiple objectives is considered and a novel local search with controlled deterioration (CDLS) is applied to minimize makespan and total tardiness simultaneously, which consists of local search step and deterioration step. A jumping condition and a Pareto-dominance based replacement principle are applied in local search. The deterioration step tries to obtain a new current solution with the controlled deteriorated degree based on e-Pareto dominance. CDLS is tested on many instances and the computational results validated the promising advantage of CDLS when compared to other algorithms.

Objective: To evaluate the characteristics of force degradation of latex elastics in clinical applications and in vitro studies. Materials and Methods: Samples of 3/16-inch latex elastics were investigated, and 12 students between the ages of 12 and 15 years were selected for the intermaxillary and intramaxillary tractions. The elastics in the control groups were set in artificial saliva and dry room conditions and were stretched 20 mm. The repeated-measure two-way analysis of variance and nonlinear regression analysis were used to identify statistical significance. Results: Overall, there were statistically significant differences between the different methods and observation intervals. At 24- and 48-hour time intervals, the force decreased during in vivo testing and in artificial saliva (P < .001), whereas there were no significant differences in dry room conditions (P > .05). In intermaxillary traction the percentage of initial force remaining after 48 hours was 61%. In intramaxillary traction and in artificial saliva the percentage of initial force remaining was 71%, and in room conditions 86% of initial force remained. Force degradation of latex elastics was different according to their environmental conditions. There was significantly more force degradation in intermaxillary traction than in intramaxillary traction. The dry room condition caused the least force loss. Conclusions: There were some differences among groups in the different times to start wearing elastics in intermaxillary traction but no significant differences in intramaxillary traction.

To improve the corrosion resistance of N80steel, Ni-W-P coating was prepared by electroless deposition. The corrosion properties for Ni-W-P coating were investigated in hypersaline ground brine. Results of weight loss tests show that the corrosion resistance of the Ni-W-P coating is 10 times of N80steel in hypersaline brine at 90 °C. Electrochemical tests show that the current density of Ni-WP coated sample reduce from 7.94×10 μA/cm to 4.28×10 μA/cm, and the corrosion potential changes from –0.700 V to –0.398 V compared with N80steel. Scanning electron microscopy (SEM) micrographs and X-ray photoelectron spectroscopy (XPS) were used to evaluate the morphology and composition of the corrosion layer of Ni-W-P coating. The results show that severe intergranular corrosion appear in N80steel, whereas no intergranular corrosion occur in NiW-P coating. The chemical composition of the corrosion layer of Ni-W-P coating is NiO,WO3, phosphate, and hypophosphite which led to superior corrosion resistance in hypersaline brine. This study confirms that the Ni-W-P coating can be applied for corrosion protection in hypersaline environment. Keywords-Ni-W-P coating; hypersaline brine; corrosion; corrosion resistance;corrosion layer

simulation, Formability Abstract. The influence of the different laser faculae model and optical field distribution with spatial frequency components on laser shock forming for TA2 titanium sheet metal was done by the binary optical beam shaper and the finite element software ABAQUS, and the dynamic response and forming rule of the deformation of TA2 titanium sheet were analyzed. The results show that after using ring distribution of low frequency light load, sheet metal loading area first produces plastic deformation, occurs the thickness to thin, and with the increase of loading time, plastic deformation area continuously outward expands; under the condition of the same peak pressure and outer diameter of ring laser faculae, the smaller the inner diameter, the greater the deformation and the flatter the bottom; compared with the circular laser faculae, the bottom of the laser shock forming deformation area is relatively flat, the deformation and the residual stress distribution are evener by ring low frequency faculae, which not only increases the performance of sheet metal forming, but also improves the fatigue strength and wear resistance of the specimens.