Plug Failure Research Articles

Spark plug failure detection using Z-freq and machine learning

Preprogrammed monitoring of engine failure due to spark plug misfire can be traced using a method called machine learning. Unluckily, a challenge to get a high-efficiency rate because of a massive volume of training data is required. During the study, these failure-generated were enhanced with a novel statistical signal-based analysis called Z-freq to improve the exploration. This study is an exploration of the time and frequency content attained from the engine after it goes under a specific situation. Throughout the trial, the misfire was formed by cutting the voltage supplied to simulate the actual outcome of the worn-out spark plug. The failure produced by fault signals from the spark plug misfire were collected using great sensitivity, space-saving and a robust piezo-based sensor named accelerometer. The achieved result and analysis indicated a significant pattern in the coefficient value and scattering of Z-freq data for spark plug misfire. Lastly, the simulation and experimental output were proved and endorsed in a series of performance metrics tests using accuracy, sensitivity, and specificity for prediction purposes. Finally, it confirmed that the proposed technique capably to make a diagnosis: fault detection, fault localization, and fault severity classification.

Investigation into the Relationship between Super-Knock and Misfires in an SI GDI Engine

The super-knock poses new challenges for further increasing the power density of spark ignition (SI) engines. The critical factors and mechanism connecting regarding the occurrence of super-knock are still unclear. Misfire is a common phenomenon in SI engines that the mixture in cylinder is not ignited normally, which is often caused by spark plug failure. However, the effect of misfire on engine combustion has not been paid enough attention to, particularly regarding connection to super-knock. The paper presents the results of experimental investigation into the relationship between super-knock and misfires at low speed and full load conditions. In this work, a boosted gasoline direct injection (GDI) engine with an exhaust manifold integrated in the cylinder head was employed. Four piezoelectric pressure transducers were used to acquire the data of a pressure trace in cylinder. The spark plugs of four cylinders were controlled manually, of which the ignition system could be cut off as demanded. In particular, a piezoelectric pressure transducer was installed at the exhaust pipe before the turbocharger to capture the pressure traces in the exhaust pipe. The results illustrated that misfires in one cylinder would cause super-knock in the other cylinders as well as the cylinder of itself. After one cylinder misfired, the unburned mixture would burn in the exhaust pipe to produce oscillating waves. The abnormal pressure fluctuation in the exhaust pipe was strongly correlated with the occurrence of super-knock. The sharper the pressure fluctuation, the greater the intensity of knock in the power cylinder. The cylinder whose exhaust valve overlapped with the exhaust valve of the misfired cylinder was prone to super-knock.

Locating the optimal microstructural state against dynamic perforation by evaluating the strain-rate dependences of strength and hardness

Intense research efforts have been made to understand the variation of strength with strain rate, while the mechanisms governing the strain-rate dependence of hardness have been rarely studied. In this work, we conducted a comprehensive investigation on strength, hardness and failure mechanism of AISI 4340 steels with 4 different microstructural states in a wide range of loading rate. We found strain-rate hardening behavior in all 4 steels, while the degree of hardening, characterized by the normalized dynamic strength (NDS) or the normalized dynamic hardness (NDH), depends on not only materials but also loading modes. With the increase of material strength, the NDS significantly increases but the NDH decreases slightly. The inconsistency between the variations of NDS and NDH is because the hardness is governed by not only yield strength but strain-hardening ability. Although the yield strength increases as rising strain rate, the strain-hardening ability reduces obviously, particularly for high-strength materials due to shear softening under dynamic loading conditions, which also causes a transition from homogeneous deformation to shear fracture. The variations of NDS and NDH could reflect the trends for resisting not only the ductile perforation (strength limited) but also the shear plugging failure (toughness limited), allowing to propose a criterion for locating the optimal strength-toughness combination against dynamic perforation, which was further verified by the ballistic penetration testing results. Moreover, similar behaviors of NDS and NDH of various other alloys were also found, which may suggest the extensive applicability of the current approach.

One-dimensional finite element limit analysis for hydraulic pile extraction

This paper presents a numerical method to efficiently calculate the required overpressure for hydraulic pile extraction. The method uses a one-dimensional (1D) model involving two steps: (1) the steady state hydraulic pressure distribution is calculated for a unit pressure using a finite element model and (2) the required overpressure is calculated using finite element limit analysis. This combined model leads to an efficient calculation tool for estimating the required hydraulic overpressure to extract the pile. The model can also capture other failure mechanisms, such as failure of the pile plug, and the 1D approach allows for alternative soil resistance formulations to be incorporated easily. This allows the method to be used for preliminary analysis as well as detailed extraction assessments for an entire wind farm site. The proposed method is applied to study a pile in sand, clay and layered soil profiles. The analyses in sand show a significant increase in the plug shaft resistance due to the hydraulic gradient, resulting in a super-linear increase of break-out pressure with embedment depth. In clay soils, the break-out pressure increases linearly, but plug failure may occur at large embedment depths. Furthermore, soil layering can have a significant effect on the break-out pressure.

Interface strengthening in dissimilar double-sided friction stir spot welding of AZ31/ZK60 magnesium alloys by adjustable probes

Dissimilar welding of AZ31/ZK60 magnesium alloys with a thickness of 2 mm was successfully carried out by the double-sided friction stir spot welding with adjustable probes. A dissimilar joint bearing flat surfaces on both sides without a keyhole was obtained and the shear failure load of 8.7 ± 0.5 kN was reached. The role of the adjustable probes has been revealed in detail. In the center of the stir zone, the welding interface structure was heterogeneous around which some distinct oxides still remained, leading to a weak interface strength. On the contrary, the welding interface structure around the shoulder/probe interface was homogeneous with no oxides giving rise to a strong interface strength, which is attributed to the severe material flow introduced by the adjustable probes. In addition, the vicinity outside the shoulder/probe interface, where the fracture occurred during the shear tensile tests, was also strengthened owing to the shearing and torsion by the adjustable probes. Therefore, a stable plug failure can be obtained and the joint properties can be improved.

The effect of Zn coating layer on the microstructure and mechanical properties of friction stir spot welded galvanized DP590 high-strength steel plates

Friction stir spot welding was successfully applied to the 1.4 mm thick galvanized DP590 dual-phase steel plates using a W-Re alloy rotating tool. During welding, a constant rotation speed of 800 rpm and a dwell time of 3 s were used and the tool penetration depth was ranged from 0 to 0.9 mm in order to study the flowing behavior and distribution of the Zn element in the joints. It was revealed that different forms of Zn were present along the interface. For example, there were Zn aggregates at the edge of the bonded interface, and there were droplet-like Zn particles along the partially bonded interface. Layers of accumulated Zn also existed outside the weld nugget. No obvious Zn element was detected inside the entire stir zone away from the interface. With the increase of penetration depth, the size of martensite in the stir zone increased from 8 to 14.2 μm. When the penetration depth was less than 0.6 mm, the shear tensile tests of the FSSW joints showed that the existence of Zn at the hook-like interfaces reduced the mechanical properties of the joints. However, when the penetration depth was larger than 0.6 mm, no noticeable effect of Zn was found for the joints with straight interfaces and a higher shear tensile load could be reached. The maximum shear tensile load was about 21.35 kN through the plug failure mode when a bonded interface of 1.9 mm was formed at a penetration depth of 0.8 mm.

Long-term outcome of the Surgisis® (Biodesign® ) anal fistula plug for complex cryptoglandular and Crohn's fistulas.

AimTo evaluate the long‐term success rate of treatment with the Surgisis® (Biodesign®) anal fistula plug for complex anal fistulas, assess fistula plug failure over time and compare success rates for fistula plug between a group of patients with cryptoglandular fistula and another group with Crohn's fistula.MethodThis is a single‐centre study of consecutive patients treated with the Surgisis® (Biodesign®) anal fistula plug between May 2006 and October 2009. All patients had complex anal fistulas in need of surgical treatment. The patients were assessed preoperatively by physical examination and three‐dimensional (3D) endoanal ultrasound, and treated with a loose seton. Postoperative assessment by clinical examination and 3D endoanal ultrasound was performed at 2 weeks, 3 months and 6–12 months. Long‐term follow‐up was carried out in 2017 using a questionnaire, and clinical examination combined with 3D endoanal ultrasound was performed if the questionnaire indicated any signs of fistula recurrence.ResultsA total of 95 patients were included; 30 had quiescent Crohn's disease. Overall, 151 plug procedures were performed. Long‐term follow‐up was undertaken in 90 (95%) patients; the results showed that after a median period of 110 months, the overall healing rate after one to five plug procedures was 38%. No statistically significant difference in success rate was found between the cryptoglandular fistula group and the Crohn's fistula group (P = 0.37). No further healing was observed after the use of three plugs.ConclusionConsidering its low morbidity in a complex disease with high recurrence rates over time, the anal fistula plug may still be considered as one of the first‐line treatments for patients with complex anal fistulas.

Clarifying effect of welding conditions on microstructure and mechanical properties of friction stir spot-welded DH590 automotive high-strength steel plates

Friction stir spot welding was successfully applied to the 1.2-mm-thick DH590 dual-phase steel plates by using a polycrystalline cubic boron nitride rotating tool. During welding, the rotation speed ranged from 600 to 1000 r/min and the penetration depth ranged from 0.1 to 0.3 mm. In the spot joints, the size of the stir zone increased with the increase in rotation speed as well as the penetration depth of the tool. Comparing with the banded ferrite and martensite structure of the base metal, a mixed microstructure of ferrite and tempered martensite, refined bainite structure and coarse martensite structure were found in the heat-affected zone, thermomechanically affected zone and stir zone of the joints, respectively. Two kinds of interfacial shapes were formed between the upper and lower steel plates, and the formation of the bonded interface was dominated mainly by the penetration depth of the rotating tool rather than the rotation speed. It was revealed that the joints with straight interfaces showed higher shear tensile loads comparing with those with hook-like interfaces. Shear tensile tests showed that the maximum shear tensile load reached about 15.56 kN when the rotation speed and penetration depth were set as 800 r/min and 0.3 mm, respectively. The specimen was fractured through plug failure mode with a total elongation of about 5.6 mm.

Effects of permeable plugs on wellbore strengthening

Wellbore strengthening (WBS) treatment uses lost circulation materials (LCMs) to seal fractures emanated from a wellbore to enhance the pressure-bearing capability of a fractured rock formation during drilling a well. The plugging zone made of LCMs to prevent high wellbore pressure from being completely transferred to fracture tip is permeable and movable. The mechanical responses of wellbore-fracture-plug systems are thus important to WBS designs. A fully coupled hydraulic fracture model is presented to simulate the evolution of near-wellbore stress, fracture opening and internal pressure for finding the way of mitigating the risk of plug failure. Laboratory results were first reported on the ranges of plug permeability and strength in producing plug failure. A symmetric bi-wing fracture geometry is employed in the model, and the roles of in situ stresses, and plug location, dimension and permeability are studied in terms of dimensionless parameters. The numerical results show that in addition to increasing hoop stress, the less permeable plug can slow pressure enhancement rate at its downstream to postpone tensile plug failure caused by increasing fracture opening. The strengthening duration prolongs in rocks under an isotropic in situ stress condition, by plugging fractures at or near their fracture mouth, moderately increasing plug length and width, and decreasing plug permeability. Not only do the time-varying results recover most of the findings obtained by the fixed pressure fracture model, but they are more suitable to the plug failure analysis because the unbalanced pressure on both sides of the permeable plug, controlling shear plug failure, varies transiently.

Metallography and Computed Tomography Analysis of the Shrinkage Cavity Formed in Advanced High-Strength Steel Resistance Spot Welds

Abstract Among various defects formed in resistance spot welds (RSW), voids or cavities formed at the center of the nugget are scarcely studied. However, it is widely accepted that such cavities significantly influence the mechanical properties of the spots, especially in advanced high-strength steels (AHSS). Nonavailability of a proper characterization technique to quantify these cavities is one of the reasons for less research in this area. Although conventional metallographic analysis portrays cavities in the nugget, the associated destructive sampling results in erroneous interpretation. To date, there is no reliable technique to quantify the size, shape, and distribution of the voids in the nugget. In this context, the present study uses a computed tomography (CT) technique to visualize and quantify the cavities in spot-welded AHSS nuggets. The images obtained using a CT scan provide a new insight into the cavity and its characteristics, such as volume and surface topology. According to the CT results, the voids formed in AHSS spots increase with the increase in base metal yield strength. Furthermore, the CT results also reveal that the conventional critical diameter of 4 × thickness1/2 to obtain plug failure in RSW is not valid for AHSS spots because of the influence of the cavity in the faying interface.

Friction stir spot welding of AA6061-T6 and Cu with preheating: Strength and failure behavior at different test temperatures

In the current study, the influence of test temperatures was investigated on lap shear strength and fracture behavior of dissimilar and similar friction stir spot-welded (FSSW) joints between Cu and AA6061-T6 sheets prepared without and with employing additional heating. Formation and distribution of intermetallic compounds (IMCs) in Cu-AA6061 FSSW joints was further appraised. An increase in maximum lap shear force was observed in Cu-AA6061 and Cu-Cu joints when preheating was employed. Lap shear force decreased with increase in test temperature for Cu-AA6061 joints prepared without preheating; however, for joints prepared employing preheating, the lap strength increased from 25 to 50 °C following a slight drop at 100 °C test temperature. For Cu-Cu joints, lap shear force also increased with test temperature for the range studied in the present work. X-ray diffraction, and energy dispersive spectroscopy analysis illustrates the formation of IMCs in the form of Al2Cu and Al4Cu9 in Cu-AA6061 and oxides in Cu-Cu joints. The interface failure from IMC rich regions in dissimilar joints was observed whereas similar joints failed under plug failure. Intermittently, thick IMC layer was observed in dissimilar Cu-AA6061 joint prepared with preheating. Presence of tearing/rupture from oxide dominated intermetallic region observed in Cu-AA6061 FSSW joints whereas dimples and micro-voids were noted in Cu-Cu joints.

Reliability modelling with redundancy—A case study of power generation engines in a wastewater treatment plant

AbstractPower generators are critical assets in wastewater treatment plants (WWTPs) in Australia and many countries. Better managing the lifetime, minimising failures, improving reliability and availability, and reducing operating and maintenance costs of the power generation assets are still challenging topics for water utilities. This case study aims to develop power generation system reliability and availability modelling considering redundancy to minimise operation and maintenance costs. The two‐parameter Weibull model was used to assess system reliability and availability to power generation engines in WWTPs. The Kaplan‐Meier method (a time‐driven estimation technique) and the log beta‐Weibull model (which is suitable for modelling censored and uncensored data) were used to analyse and validate the modelling results. Shape and scale parameters of the Weibull models were estimated by maximising the log‐likelihood function using non‐linear optimisation. Hazard and reliability functions were calculated using the Weibull model. Results using two‐parameter Weibull, Kaplan‐Meier, and log beta‐Weibull models display low reliability and high hazard rate over time, which was associated with spark plug failure due to a suboptimal start and stop operation strategy.

Analogue experiments on the rise of large bubbles through a solids-rich suspension: A “weak plug” model for Strombolian eruptions

Physical interactions between bubbles and crystals affect gas migration and may play a major role in eruption dynamics of crystal-rich magmas. Strombolian eruptions represent an end member for bubble-crystal interactions, in which large bubbles (significantly larger than the crystal size) rise through a crystal-rich near-surface magma. Indeed, volcanoes that produce Strombolian eruptions often generate ejecta with > 30 vol% (often > 45 vol%) average crystallinity. At Stromboli Volcano, Italy, average crystallinity can reach 55 vol%, which is approaching the eruptibility limit for magmas. At such high crystallinities the solids interact mechanically with each other and with bubbles. This complex rheology complicates the two-phase (liquid-gas) slug flow model often applied to Strombolian eruptions. To examine the effect of crystals on bubble rise, we performed analogue experiments in which large bubbles rise in a vertical tube filled with silicone oil and polypropylene particles. The particles have a slightly lower density than the oil, and therefore form a layer of oil + particles at the upper surface. We varied surface pressure, particle volume fraction, length of the particle-bearing cap, and bubble size to examine the ways in which these parameters influence Strombolian-type eruptions. We show that in experiments, suspended solids begin to affect bubble rise dynamics at particle volume fractions as low as 30 vol% (or, when divided by the random close packing value, a normalized particle fraction φ=0.64). Bubbles in experiments with higher particle contents deform as they rise and burst through a small aperture, generating surface fountains that begin abruptly and decay slowly, and longer-lasting acoustic signals of lower amplitude than in particle-poor experiments. Particle fractions > 38 vol% (φ>0.80) generated strong deformations on fast-expanding bubbles that applied a high stress on the cap, but they trapped bubbles that were less overpressured. Qualitatively, the gas release behavior observed in particle-rich experiments is consistent with observations of Strombolian eruptions. Moreover, we estimate that the observed crystallinity of pyroclasts at Stromboli volcano represents φ>0.8. From this we suggest a “weak plug” model for Strombolian eruptions that evolves towards a low-viscosity equivalent of Vulcanian-style plug failure with a more crystalline, stronger, and less permeable plug. Importantly, this model allows the rise of several bubbles in the conduit at the same time and suggests that longer-lasting, more pulsatory and complex eruptions may reveal an increase in near-surface crystallinity, shedding some light on changing conduit conditions that could help determine the different gas rise regimes involved in passive degassing, puffing, and different expressions of Strombolian explosions.

Fatigue Behaviors of Resistance Spot Welds for 980 MPa Grade TRIP Steel

The fatigue life of the resistance spot weld of 980 MPa grade transformation induced plasticity (TRIP) steel was investigated and failure modes and fracture surfaces according to the fatigue load were analyzed. The fatigue life according to the nugget size was observed by using two electrodes with face diameters of 8 mm and 10 mm. When an electrode face diameter with 10 mm was used, the nugget size was large, and the fatigue life was further increased. After the fatigue test, three types of failure modes were observed, namely pull-out, plug, and heat affected zone (HAZ) failure, depending on the fatigue load. The fracture surfaces in each failure mode were analyzed. In all failure modes, a crack was initiated in the HAZ region, which is the interface between the two materials in all failure modes. In the case of pull-out failure, the crack propagates as if it surrounds the nugget at the outer edge of the nugget. In the case of HAZ failure, the crack propagates in the thickness direction of the material and outward in the nugget shell. Plug failure occurs with pull-out failure and HAZ failure mixed. The propagation patterns of cracks were different for each failure mode. The reason why the failure mode and the fracture surface are different according to the fatigue load is that the propagation speed of the fatigue crack is fast when the fatigue load is relatively large and is slow when the fatigue load is low.

Effect of iridium spark plug gap on emission, noise, vibration of an internal combustion engine

The most important factors affecting comfort and performance in motor vehicles are; The exhaust gases generated by the internal combustion engine are noise and vibration. The effect of these factors can be reduced thanks to the fully efficient and regular operation of the engine. The most important part affecting the efficient operation of the spark plug ignition engine is the spark plug. Spark plug failure; emission, noise and vibration values increase. These negative effects reduce vehicle comfort and increase travel costs; it also causes more damage to nature. Vehicles are designed and manufactured to ensure optimum operating parameters during production. However, changes in these parameters occur as the vehicle is used and different types of parts are used during maintenance. In this study, spark plug nail spacing; Emission, noise and vibration effects and determination of optimum nail spacing. In the experiments, iridium spark plug was used as ignition spark type. The spark plugs wear out because the engine fires continuously during operation. This wear increases the distance between the center electrode and the electrode cap and changes the resulting spark quality. According to the experiments; When the iridium spark plug nail spacing is 0.8 mm, the noise is optimum at different revolutions, the vibrations in the 0.9 mm nail spacing increase at low revolutions, and the hydrocarbon value is minimized at high revolutions in the 0.8 mm spark plug nail spacing.

Influence of the pulsed current pattern on cross-tension strength of spot-welded joint with nugget diameter variation. Development of resistance spot welding with a pulsed current pattern for ultra-high-strength steel sheets

ABSTRACT Advantageous effect on cross-tension strength (CTS) of resistance spot welds by ‘pulsed current pattern’ has been evaluated assuming nugget diameter variation which unexpectedly causes deterioration of joint strength of ultra-high-strength steel (UHSS) in auto assembly lines. The pulsed current pattern is newly developed resistance spot welding method consisting of the main welding for forming nugget and multiple combinations of short-time cool time and short-time high-current post-heating (pulsed current) to realize the time-effective change in a brittle nugget. For quantitative evaluation of nugget diameter variation and post-heating effects, various welding experiments and numerical simulations are conducted by various main welding currents without or with 1- or 2-time pulsed current using 1180 MPa grade steel sheets. The experimental results clarify 2-time repetitions of pulsed current ensures plug failure and high CTS over 10 kN at a wider range of nugget diameter than without and even with the 1-time pulsed current. Numerical calculation and cross-sectional microstructures suggest that post-heating with too small nugget diameter overheats nugget and partially remelts phosphorus-rich area due to solidifying segregation leading to low CTS, but repetitive-pulsed current can lower peak temperature to appropriate range to avoid deterioration of CTS. Therefore, the pulsed current pattern is expected to realize high-quality joint even when nugget diameter is insufficient due to instability of welding processes.

Efficacy of Plug Treatment for Complex Anorectal Fistulae: Long-term Danish Results.

PurposeBioprosthetic plugs are appealing, allow simple, repeatable applications, preserve sphincter integrity, minimize patient discomfort, and allow subsequent surgical options when needed. However, success rates vary widely. This study assessed the healing rate in our department when both the Cook-Surgisis and the Gore fistula plugs were used and the long-term effectiveness of using anal plugs for managing anal fistulae.MethodsA chart review was performed for patients who had undergone plug insertion between January 2008 and December 2015 at Copenhagen University Hospital, Hvidovre. Data were collected through a prospectively collected database. Plugs were inserted according to guidance provided by 2 experienced surgeons. Long-term results were determined by clinical visits 3, 6, and 12 months after surgery and once yearly thereafter.ResultsFrom 2008 to 2015, 36 fistula plugs were inserted. During the follow-up period with a median duration of 18 months (range, 7–60 months), the fistulae of 52.8% of the patients healed. The plug failure rate was 44.4%, and the fistula recurrence rate was 26.3%. The median time to recurrence was 12 months. The overall success rate for plug treatment in our department was 39% when adjusted for recurrence.ConclusionThe use of bioprosthetic plugs to treat patients with complex anal fistulae seems to be a safe, viable option for complex fistula repair when other surgical attempts have failed. However, it should not be the treatment of choice. Further prospective randomized studies with a sufficient sample-size and standardized measurements are necessary to evaluate the efficacy of fistula plugs fully.

A thermodynamically consistent peridynamics model for visco-plasticity and damage

This article presents a unified visco-plastic-damage model in the peridynamics set-up which may be applied across different regime of strain rates and temperatures. In the model, we introduce two internal variables, one describing plastic flow and other the damage in the material. Exploiting the idea of master balance, in addition to the conventional momentum balances, we postulate micro-force balances for both plastic flow and damage evolution in terms of additional peridynamic force states. The equations of motion are in the form of integro-differential equations and do not require continuity of field variables. Using the idea of energy equivalence and entropy equivalence, constitutive relations for the peridynamic force states are determined. The proposed peridynamic visco-plastic-damage model may be thought as a non-trivial extension of the recently developed peridynamic visco-plasticity model (Rahaman et al.,2017). The current scheme couples the visco-plasticity and damage in a thermo-dynamically consistent manner and provides temperature evolution which reflects contribution from both plasticity and damage. The efficacy of the model is demonstrated through simulations of the adiabatic shear band propagation as observed in Kalthoff–Winkler experiment and the shear plugging failure of Weldox 460 E steel plates along with the determination of the ballistic limit.

Friction stir spot welding of SPCC low carbon steel plates at extremely low welding temperature

Friction stir spot welding (FSSW) was applied to 2.0 mm thick steel plate cold-rolled commercial (SPCC) low carbon steel plates at a very low rotation speed that ranged from 5 to 50 rpm, which was much lower than that generally used for the conventional FSSW technique. Due to the very low heat input, the welding processes could therefore be completed at a peak welding temperature below 160 °C. As a result, a significantly refined microstructure with an average grain size of about 0.41 μm was formed in the stir zone of the joints and the J1{0–11}<−211> and J2{1–10}<−1–12> shear textures were the dominant components, which are different from the D1{11–2}<111> and D2{−1–12}<111> shear textures formed in the conventional FSSW joints. In addition, no heat affected zone could be detected along the cross-sectional plane of the joints. Although a few void-like non-bonded areas were still observed along the interface between the upper and lower steel plates, the shear tensile loads of the joints increased to about 10.0 kN when welded at a condition of 8 t, 20 rpm and 30 s, and the joints fractured through the plug failure mode.

Application of the modified Mohr–Coulomb fracture criterion in predicting the ballistic resistance of 2024-T351 aluminum alloy plates impacted by blunt projectiles

The majority of current finite element (FE) simulations on shear plugging adopted Lode independent fracture criteria, and the value of utilizing a Lode dependent fracture criterion in predicting the ballistic resistance of metallic plates undergoing shear plugging has not been well understood. A group of 12.65 mm diameter blunt rigid projectiles were fired against 9.94 mm thick 2024-T351 aluminum alloy plates by using a one-stage gas gun in the impact velocity range of 133.4 m/s∼363.8 m/s. A failure mode of Shear plugging was observed in the test and the ballistic limit was obtained by fitting the initial and residual velocity data. A 3D FE model corresponding to the test was built in ABAQUS and then was adopted to predict the ballistic resistance and fracture behavior of the target. In the simulations, a slightly modified Johnson–Cook constitutive relation was companied with either the Lode dependent Modified Mohr–Coulomb (MMC) fracture criterion or the Lode independent original Johnson-Cook fracture criterion. It was found that the FE model using the MMC fracture criterion predict the ballistic limit and shear plugging behavior in good accordance with that obtained in the tests. In contrast, the simulations using the Johnson–Cook fracture criterion over-predicted the ballistic limit by 28.5% although the shear plugging failure pattern was reasonably predicted. Detailed analysis shows that the dominant stress state of the material in the shear plugging band is nearly shear, where the Lode angle has an obvious influence to reduce the fracture strain of the metal comparing with axial symmetric conditions. FE simulations by using fictitious metals with the same fracture data at axial symmetry tension but different fracture stain at shear also confirm that the ballistic resistance of a metal plate is much dependent on the effect of the Lode angle on a material's ductility.