Microscopic Fracture Research Articles

Parametric experimental investigation of additive manufacturing-based distal ulna bone plate: a response surface methodology-based design approach

Purpose The implications of metallic biomaterials involve stress shielding, bone osteoporosis, release of toxic ions, poor wear and corrosion resistance and patient discomfort due to the need of second operation. This study aims to use additive manufacturing (AM) process for fabrication of biodegradable orthopedic small locking bone plates to overcome complications related to metallic biomaterials. Design/methodology/approach Fused deposition modeling technique has been used for fabrication of bone plates. The effect of varying printing parameters such as infill density, layer height, wall thickness and print speed has been studied on tensile and flexural properties of bone plates using response surface methodology-based design of experiments. Findings The maximum tensile and flexural strengths are mainly dependent on printing parameters used during the fabrication of bone plates. Tensile and flexural strengths increase with increase in infill density and wall thickness and decrease with increase in layer height and wall thickness. Research limitations/implications The present work is focused on bone plates. In addition, different AM techniques can be used for fabrication of other biomedical implants. Originality/value Studies on application of AM techniques on distal ulna small locking bone plates have been hardly reported. This work involves optimization of printing parameters for development of distal ulna-based bone plate with high mechanical strength. Characterization of microscopic fractures has also been performed for understanding the fracture behavior of bone plates.

Effects of pre-static loads on the dynamic pure mode I and mixed mode I–II fracture characteristics of rocks

Rocks in deep underground engineering are prone to encounter pre-static loads and dynamic disturbances simultaneously. Meanwhile, pure mode I and mixed mode I–II fractures are common in brittle materials including rocks. Understanding the mode I and mixed mode I–II fracture mechanisms of rocks subjected to coupled static-dynamic loads is thus imperative and beneficial to the stability of underground rock engineering structures. In this study, using the improved split-Hopkinson pressure bar (SHPB) loading system, coupled static-dynamic mode I and mixed mode I–II fracture tests are conducted on notched semi-circular bend (NSCB) granite specimens. With the aid of high-speed digital image correlation (HS-DIC), 3D scanning technology and scanning electron microscope (SEM), the effects of pre-static loads on dynamic fracture characteristics of granite are comprehensively investigated. Experimental results show that both the dynamic and total fracture toughness reveal evident rate dependence. At a fixed loading rate, the dynamic fracture toughness decreases with increasing pre-static loads, while the total fracture toughness barely changes, indicating that the enhanced rate sensitivity compensates for the weakening effect induced by the pre-static load. The progressive fracture progress shows that with the increase of pre-static loads, the crack initiation time of the specimen is shortened and the crack propagation velocity increases. 3D scanning results show that the fractal dimension of the fracture surface continues to rise as the pre-static load increases, illustrating the fracture surface becomes rougher. In addition, the connection between macroscopic fracture characteristics and microscopic fracture mechanism of granite subjected to static-dynamic loading is discussed by SEM. The quantity and size of the micro-defects inside the internal structure of rocks increase with increasing pre-static load, revealing that the pre-static load degrades rock structure and leads to a negative response to dynamic fracture toughness.

Management of Cartilage Lesions Based on Etiology : OCD versus Acute Traumatic Lesions

Treatment of articular cartilage lesions in the knee remains a challenge. A wide range of options is available nowadays, including conservative measures, simple arthroscopic interventions, marrow tapping techniques, osteochondral auto/allografting, cell-based techniques, growth factors and emerging gene therapy techniques. Osteochondritis dissecans (OCD) is first described by Konig in 1888. Its prevalence is estimated at 15 to 30 cases per 100.000. The lateral aspect of the medial femoral condyle is the classic site, repetitive trauma with microscopic fractures below the surface of the joint of clogging of the tiny blood vessels inside the bone associated with a number of differing medical conditions. OCD is commonly found in older children and adolescents who actively participate in sports. It is different from acute traumatic cartilage lession, as they happen due to a direct compaction injuries, such as occur in the patellofemoral joint. The more common mechanism is a rotational injury to the knee or shearing force across the articular cartilage. Patellar dislocation may lead to osteochondral fracture through this mechanism and is responsible for 40-50% of osteochondral lesions around the femoral condyles. It is most common in young active patients aged 20-40 years. Treatment options are variable and dependent on many factors, including patient age and activity level, location and size of the defect, meniscal status, limb alignment, concomitant knee pathologies, chronicity, and comorbidities. Treatment of cartilage lesions is differentiated not based on its etiology but based on the severity of the cartilage lesions such as size, depth, shape and description of the walls (contained, partially contained or opened), and the resource capabilities of each centre. What needs to be understood is that OCD lesions are disease-related, whereas acute traumatic lesions may occur in otherwise healthy cartilage due to mechanical trauma.

NANOINDENTATION EXPERIMENTS TO STUDY THE MICROMECHANICAL PROPERTIES OF STRATIFIED SHALE

The micromechanical properties of stratified shale are critical for understanding wellbore stability and hydraulic fracture extension patterns. Based on nanoindentation experiments and data analysis, the mechanical parameters of shale specimens from two laminar directions of the Jimsar Lucaogou Formation in Xinjiang are measured from a microscopic perspective in this paper. The mechanical parameters of multiple indentation points are obtained using grid indentation. The mineral composition of the samples is quantified using field emission scanning electron microscopy (SEM) and XRD ray diffraction. The results show that the shale mechanical parameters have a good linear relationship with each other at the nanoscale. However, the relationship between horizontal bedding and vertical bedding is quite different. The average elastic modulus, average hardness, and average fracture toughness of the parallel laminated specimens are 22.94 GPa, 1.04 GPa, and 1.19 MPa·m<sup>1/2</sup>, respectively. The average elastic modulus, average hardness, and average fracture toughness of the vertical laminated specimens are 35.23 GPa, 3.47 GPa, and 1.32 MPa·m<sup>1/2</sup>, respectively. The shale mechanical parameters in the vertical bedding direction are higher than those in the horizontal laminae. The mechanical parameters at the nanoscale are related to the orientation of the laminae. The shale is anisotropic at the nanoscale and the anisotropy of different mechanical parameters behaves differently. The microscopic elastic modulus, hardness, and fracture toughness of shale conform to Weibull distribution. The dispersion of hardness is the highest. The results can help analyze the relationship between shale mechanical properties and laminar orientation.

ZrB 2–SiC spiral fibers prepared by combining liquid rope effect with non-solvent-induced phase separation method: A promising toughening material for ultra-high temperature ceramics

Spiral fibers were considered to be an ideal toughening phase of ultra-high torsional release effect. In this work, ZrB₂ (Z)–20 vol% SiC (S) spiral fiber (ZS_sf) with controllable structure was prepared by a combination approach of liquid rope effect and non-solvent-induced phase separation. Dominantly depended on the kinematic viscosity (<i>η</i>), dropping height (<i>H</i>), and flow rate (<i>Q</i>), the geometric parameters of ZS_sf involving filament diameter (<i>d</i>) and coil diameter (<i>D</i>) were followed the relationship of <i>d ≈</i> 0.516×10⁻³<i>Q</i>^1/2<i>H</i>^−1/4 and <i>D ≈</i> 0.25×10^–3(<i>Q</i>/<i>H</i>)^1/3, respectively, within the optimized <i>η</i> of 10–15 Pa·s. Three different microstructures of ZS_sf were achieved by adjusting the polymer/solvent/non-solvent system assisted with phase diagram calculation, including dense, hollow, and hierarchical pore structures. The ZrB₂–SiC with 1 wt% ZS_sf composites prepared by hot isostatic pressing (HIP) exhibited a ~30% increase in fracture toughness (<i>K</i>_IC, 4.41 MPa·m^1/2) compared with the ZrB₂–SiC composite, where the microscopic fracture toughness of the ZS_sf was ~80% higher than that of the matrix. The fibers with a ~10 nm <i>in-situ-</i>synthesized graphite phase amongst grain boundaries of ZrB₂ and SiC changed the fracture mode, and promoted the crack deflection and pull-out adjacent the interface of matrix and the fiber.

Fracture Analysis of Tube-gusset-intersecting Joint Based on SWDM Microscopic Fracture Mechanism

Fracture Analysis of Tube-gusset-intersecting Joint Based on SWDM Microscopic Fracture Mechanism

A Strength Criterion for Deep Rock with Stochastic Fractures via DEM Simulations

Criteria for rock strength mostly focus on macromechanical parameters, which cannot directly explain the relationship between microscopic fracture characteristics and strength. This paper analyses the strength characteristics of deep jointed rock with stochastic fractures by the distinct element method (DEM) and proposes a new strength criterion. First, an improved bond contact model and the smooth-joint contact model are implemented within the framework of DEM to simulate the characteristics of deep rock. Then, triaxial compression tests on Berea sandstone are also numerically simulated under various confining pressures and fracture intensities (P32). Finally, a strength criterion is proposed and validated based on the numerical and experimental results. The criterion can capture the nonlinear relationship between the major principal stress and the confining pressure and reveal the microscopic fracture characteristics of deep rock. However, the criterion does not consider the influence of the intermediate principal stress. The average deviation between all the predicted strengths and the experimental results is 5.12%, which demonstrates that the criterion has good applicability.

Study on Microscopic Fracture Surface Analysis based on Deep Learning (1) : Fracture Surface Classification by Convolutional Neural Network

Study on Microscopic Fracture Surface Analysis based on Deep Learning (1) : Fracture Surface Classification by Convolutional Neural Network

Mechanical properties and fractographic analyses of FeCo-2V alloy heat-treated around order-disorder transition temperature

The effect of heat treatment on the mechanical properties of FeCo-2V alloy was investigated at temperatures slightly above and below its order-disorder transition point with varied holding times and cooling rates. The fracture surface, grain size, and recrystallized microstructure were characterized by SEM and EBSD. The correlation between yield strength and microstructural features was analysed. Yield strength was found to decrease with the elevation of heating temperature, extension of holding time, and decrease in cooling rate. Fast cooling significantly improved the mechanical strength and ductility. The quenched samples exhibited microscopically ductile fracture features with shallow dimples on the fractured surface, while the slow-cooled ones displayed brittle microscopic fracture features, regardless of the heating temperature and holding time. The yield strength follows two separate Hall-Petch relationships for samples dominantly in the ordered and disordered states. Our analyses reveal that the mechanical strength of FeCo-2V alloy is mainly controlled by the grain size, thus it is important to regulate the grain recrystallization and growth during the heat treatment process.

Experimental investigation on the fracture surface features of heat-treated red sandstone containing fissure under constant amplitude low cycle impact using 3D digital reconstruction

Fractured rocks as typical engineering materials are commonly exposed to temperatures and dynamic perturbations. In this paper, constant amplitude low cycle (CALC) impact tests were carried out on red sandstone containing a single fissure (0°, 30°, 60° and 90°) after thermal treatment (25 °C, 200 °C, 400 °C, 600 °C and 800 °C) utilizing a modified split Hopkinson pressure bar (SHPB). Subsequently, the fracture surfaces of the failure specimens were digitally reconstructed based on point cloud data captured by a three-dimensional (3D) laser scanning. And scanning electron microscopy (SEM) was also employed as a complementary tool to study the fracture micromorphology. The fractal and rough features of fracture surfaces based on the box-counting method and image segmentation method were investigated, respectively. Meanwhile, four second-order statistics in the grayscale co-occurrence matrix (GLCM) of the digitized fracture surface after grayscale processing were calculated to describe the fracture surface texture. The best-fit multiple regression models between the fracture surface feature parameters and the interaction of temperatures and fissure angles were constructed and analyzed. Moreover, the relationships between the fracture surface features and the mechanical parameters as well as the intrinsic mechanisms were analyzed and discussed in detail. The results demonstrate that the fractal dimension (DC), joint roughness coefficient (JRC), maximum elevation difference (MD), roughness characterization factor (ω), and GLCM second-order statistics possess specific response patterns to the temperatures and fissure angles. Whether the sensitivity in portraying the fracture surface features to the interaction of temperatures and fissure angles or the reliability of the best-fit multiple regression models, the shadow method based on image segmentation behaves more promisingly. Furthermore, conspicuous correlations can be found between both the feature parameters including the GLCM second-order statistics and the failure strength, strain rate as well as life. The high temperature activates thermal activation mechanisms that alter the potential crack sources and pathways in the grain and rock skeleton, affecting the microscopic fracture face morphology. Finally, the maximum tensile stress at the edge of the prefabricated fissure might be responsible for the angle effect exhibited by the feature parameters.

A Novel Carbon Dioxide Phase Transition Rock Breaking Technology: Theory and Application of Non-Explosive Blasting

As a non-explosive low-disturbance rock breaking technology, carbon dioxide phase transition blasting (CDPTB) is widely used in rock breaking projects such as pressure relief and permeability enhancement in coal mines, open-pit mining, road subgrade excavation, foundation pit excavation, etc. In this paper, the principle and equipment of CDPTB are systematically analyzed, and the characteristics of a reusable fracturing tube and disposable fracturing tube are determined. Different energy calculation methods are analyzed to determine the magnitude or equivalent explosive equivalent of CDPTB. According to the characteristics of impact stress wave and high-pressure gas, the cracking mechanism of CDPTB is proposed. Under the action of medium-impact stress, rock mass will produce multi-point cracking, and high-pressure gas will produce a gas wedge effect in the initial fracture, which determines the comprehensive action path of the stress wave and high-pressure gas. In terms of fracture characteristics, the fractal method is used to evaluate the macroscopic crack and fragment, microscopic fracture and pore characteristics. In terms of vibration characteristics, the attenuation law of CDPTB vibration with distance is statistically analyzed, and the Hilbert–Huang transform method is used to analyze the time–frequency characteristics of CDPTB. This rock breaking technology can be widely used in different projects, and the existing problems and future challenges are put forward.

Effect of laser scanning angle on shear slip behavior along melt track of selective laser melted 316L stainless steel during tensile failure

The improved mechanical properties have been recently realized in 316 L stainless steel (SS) materials processed by additive manufacturing (AM) techniques, owing to its cross-scale structure, especially the formation of cell-structure. However, their heterogeneous structure also inevitably leads to significant mechanical anisotropy which may impede their further applications. For revealing the impact of microstructural heterogeneity on anisotropic properties of AM processed parts, this work prepared 316 L SS components using selective laser melting (SLM) techniques under different laser scanning angles. Their tensile performances are examined, and the relationship between the origin points of deformation failure and molten pool boundary is established. The results show that when the laser scanning angle is parallel with the tensile loading direction, the elongation of 316 L stainless steel fabricated by SLM is the highest, reaching 52.5%. Meanwhile, the maximum yield strength of 687.5 MPa was obtained when the laser scanning angle was 30–45°. The main reason is that the mechanical properties of the SLM parts change with the adjustment of scanning angle due to the effect of short edge grain size and poor orientation of the low grain. So, this study will provide new insights into the microscopic fracture mechanism in SLM parts.

Fracture behavior of Grade 10.9 high-strength bolts and T-stub connections in fire

High-strength bolts have been widely used in steel bolted connections, and fire-induced high temperatures will affect its basic mechanical properties and fracture behavior, leading to failure of the connection and even collapse of the overall structure. Tensile experiments are conducted on Grade 10.9 high-strength bolts to investigate the effect of stress triaxiality and heating history on their mechanical and fracture properties in the whole process of fire. The true stress-strain curves are obtained, and microscopic fracture mechanism is analyzed by SEM. The SMCS fracture model is calibrated based on test results, and parametric studies are conducted on fracture performance of T-stub connections in fire. The experimental results show that the material properties in the heating-cooling stage depend on the maximum temperature, which is inaccurate and unsafe if being replaced by those in the heating stage. The fracture performance of high-strength bolts is greatly affected by maximum and target temperatures, and the bolt ductility increases with the increase of temperatures, up to 3.5 times the ambient-temperature value. High-strength bolts exhibit ductile fracture characteristics in the whole process of fire, and the SMCS model can effectively predict the fracture behavior of Grade 10.9 high-strength bolts for a stress triaxiality range of 0.3 to 1.2. The ductility factor of T-stub connections is related to its failure mode with a variation range of 0.6 to 1.6. It is necessary to consider the fracture performance of high-strength bolts for determining the bearing capacity of bolted connections in the whole process of fire.

Thickness effect on the mechanical properties of nacre in Hyriopsis cumingii under three-point bending

To reveal the thickness dependence of nacre, the mechanical properties and microstructure of nacre with different thicknesses have been studied under three-point bending tests and SEM observations. The results show that the mechanical properties of nacre depend not only on the properties of the material itself, but also on the specimen thickness. The bending strength and fracture energy increase with decreasing specimen thickness, and the thinner specimens present better bending resistance than the thicker specimens. The mechanical properties of nacre have a significant thickness effect, and to characterize the variation of the thickness effect, the thickness effect sensitivity has been proposed. It is noteworthy that the difference in microscopic fracture modes of staggered “brick-bridge-mortar” structure is one of the factors affecting the thickness effect on the mechanical properties of nacre. Finally, the thickness effect on the bending strength is analyzed using the modified Weibull scaling law and Type-I scaling law, and the range of the thickness effect of nacre is indicated.

Influence of Aging on the Fracture Characteristics of Polyetheretherketone Dental Crowns: A Preliminary Study.

Although polyetheretherketone (PEEK) is becoming more widely used in dentistry applications, little is known about how aging will affect this material. Therefore, this study aimed to investigate the influence of an aging treatment on fracture characteristics of PEEK dental crowns. Additionally, the impact of the addition of titanium dioxide (TiO2) into PEEK was examined. Two types of commercial PEEK discs were used in this study, including TiO2-free and 20% TiO2-containing PEEK. The PEEK dental crowns were fabricated and aging-treated at 134 °C and 0.2 MPa for 5 h in accordance with the ISO 13356 specification before being cemented on artificial tooth abutments. The fracture loads of all crown samples were measured under compression tests. Results demonstrated that adding TiO2 enhanced the fracture load of PEEK crowns compared to TiO2-free PEEK crowns before the aging treatment. However, the aging treatment decreased the fracture load of TiO2-containing PEEK crowns while increasing the fracture load of TiO2-free PEEK crowns. The fracture morphology of TiO2-containing PEEK crowns revealed finer feather shapes than that of the TiO2-free PEEK crowns. We concluded that adding TiO2 increased the fracture load of PEEK crowns without aging treatment. Still, the aging treatment influenced the fracture load and microscopic fracture morphology of PEEK crowns, depending on the addition of TiO2.

Exceptional energy absorption characteristics and compressive resilience of functional carbon foams scalably and sustainably derived from additively manufactured kraft paper

To incentivize carbon sequestration activities, kraft paper, a renewable and recyclable bioproduct that is already manufactured at scale, is proposed as feedstock for producing economically viable carbon materials. The paper was first additively manufactured into 3D open cell honeycombs and closed cell plate lattices using a sheet lamination process before being pyrolyzed into paper-derived architected carbon foams (PDACFs). In the isostress orientation, PDACFs displayed low moduli, high elastic strains (~ 30–40%) and a compressive resilience similar to graphene aerogels, but at stresses up to ~ 3 orders of magnitude higher, despite the brittle nature of the carbonized fibers. In the isostrain orientation, PDACFs exhibited better moduli (~ 1 MPa – 1 GPa), which were comparable to conventional carbon foams, and smaller elastic strains (~ 5–10%). Failure in isostrain orientation proceeded by fracture propagation through and/ or between the layers while cracks in the isostress orientation extended mainly across the layers. The strength of the PDACFs (~ 0.2 – 14 MPa) was similar in both orientations, however, likely because both interlayer and intralayer failure onset involved microscopic fractures initiating and propagating through a multitude of carbonized fiber interfaces. Notably, Honeycombs and Plate Simple Cubic PDACFs exhibited a combination of strength (> 3 MPa) and energy absorption (> 1 MJ/m 3 ; > 1 kJ/kg) not found in porous carbon materials previously, suggesting that the hierarchical arrangement of carbonized fibers within a macroscopic lattice architecture is better for dissipating energy than the tetrakaidecahedron microstructure commonly found in foams. Furthermore, as an electrode in a Li-ion battery, the carbonized cellulose making up PDACFs showed reversible specific capacities of 65–140 mAh/g at a specific current of 10 mA/g for 300 cycles, which is comparable to that of commercial lithium manganese oxide batteries and graphitic anodes derived from non-renewable polymer foams. Closed cell and open cell carbon lattices, realized through a novel additive manufacturing method and pyrolysis of eco-friendly kraft paper, displayed energy storage properties, as well as combinations of compressive resilience, energy absorption and strength unmatched by current porous carbon materials. • Novel ERASL technique was introduced to fabricate closed cell plate lattices and open cell honeycomb lattices. • Lattices were made from kraft paper and pyrolyzed into Paper-Derived Architected Carbon Foams (PDACFs). • PDACFs exhibited an unprecedented combination of strength (> 3MPa) and energy absorption (> 1 MJ/m 3 and > 1 kJ/kg). • PDACFs displayed high compressive resilience similar to graphene aerogels, but at stresses up to 1000X higher. • As a Li-ion battery anode, PDACF showed reversible specific capacities of 65 – 140 mAh/g for 300 cycles.

Cause analysis of the cooler leakage in a stirling engine

After a stirling engine operated for 1750 h, the cooler in the engine was found leaking. The leakage led to a rapid decrease of the cycle efficiency. After dismantling, a cooling tube was found leaked by air pressure test. Through macro- and microscopic fracture morphologies, the cause of the leakage was determined as fatigue under alternating stress during operation, but the fatigue source region shows abnormal brittle fracture morphologies. By XRT and inner wall inspections, more cracks initiated from the extrusion bands on the inner wall, and F-containing lubricant was also detected there. Considering the fabrication process of the tube, the formation mechanism of the inner cracks is determined as hydrogen environment embrittlement (HEE) under the conditions of the local surface damage, deformed microstructure and pure hydrogen circumstance during bright annealing. Remedial methods are also proposed to increase the service life and service safety.

Finite element analysis of microscopic fracture process in titanium metal matrix composite shafts using a unit cell approach

The aim of this study is to investigate the microscopic fracture process in titanium metal matrix composites (TiMMC) shafts based on finite element (FE) analysis. A unit cell approach is used as a tool to design a representative volume element to explain the complex failure phenomenon on a microscopic level. FE mesh convergence is examined and validated with the equivalent plastic strain and contact pressure. The accuracy of the numerical modelling is verified by comparison with experimental investigations on fractured TiMMC shafts. The results show that FE modelling can successfully analyse the complicated fracture process that occurs on a microscopic scale of TiMMC shafts.

Experimental Study on Fatigue Performance of M60 High-Strength Bolts with a Huge Diameter under Constant Amplitude Applied in Bolt–Sphere Joints of Grid Structures

The high-strength bolts’ fatigue is critical for the bolt–sphere joints of grid structures under the action of suspended cranes. High-strength bolts with a huge diameter are used more commonly when the span of grid structures and the burden of suspended cranes increase. However, few works have explored the fatigue performance of high-strength bolts with a huge diameter in bolt–sphere joints of grid structures. Thus, this paper examines M60 high-strength bolts with a huge diameter used in the bolt–sphere joints of grid structures. To this end, an AMSLER fatigue testing machine performed fatigue tests on 27 specimens under constant amplitude. The stress–fatigue life (S–N) curve was obtained by regression analysis and the corresponding constant-amplitude fatigue design method was established. The test results were compared with those of high-strength bolts in other specifications. The results showed that the M60 high-strength bolt has a higher fatigue strength. Furthermore, scanning electron microscopy (SEM) analyzed the macroscopic and microscopic fatigue fracture of the specimens, and the mechanism of the fatigue failure was examined. Our findings provide important experimental data for revising relevant Chinese and international codes and promote the application of high-strength bolts with a huge diameter used in the bolt–sphere joints of grid structures with suspended cranes. This study could fill the gap of fatigue performance data of high-strength bolts in different specifications for bolt–sphere joint grid structures, and provide a basis for further studies.

Study of Blast Mitigation Performance and Fracture Mechanism of Polyurea under Contact Explosion.

In order to further study the blast mitigation performance of polyurea and to investigate the protection mechanism and damage characteristics of polyurea-protected structures under contact explosion loads, based on earlier work, this paper investigated the response and energy absorption performance of polyurea under various frequency loads. Qtech T26 blast mitigation polyurea (T26 polyurea) was adopted to protect the reinforced concrete (RC) slab and damage analysis of the post-explosion specimens was carried out at micro and macro levels. The response and energy absorption capacity of the material towards different frequency loads were investigated by dynamic mechanical analysis (DMA). Protective performance of T26 polyurea on RC slab was examined with a 10 kg TNT contact explosion test. Scanning electron microscopy (SEM) was employed to analyze the microscopic fracture morphology of the typical areas of the coating after the explosion. The chemical structure changes of the blast-face coating before and after the explosion were compared by Fourier transform infrared spectroscopy (FTIR). The results show that the glass transition region of T26 polyurea is −40 °C to 10 °C, which is a large temperature range, and the microphase separation of T26 polyurea is low. It is significantly influenced by the ambient temperature and loading frequency. The energy absorption of T26 polyurea is realized through the interaction between the hard and soft segments. When the frequency is between 102 Hz and 106 Hz, the loss factor of T26 polyurea is between 0.20 and 0.31, which exhibits a good energy dissipation performance. In the contact explosion of 10 kg TNT, the fragmentation rate of the coated specimen decreased significantly compared with that of the unprotected specimen, realizing the zero fragmentation protection effect on the back-blast face. The maximum deformation area and the main energy absorption area of T26 polyurea under contact explosion is the ring area outside the longitudinal deformation area. The chemical structure of T26 polyurea changed significantly after the explosion; typically the N-H bonds, etc., were broken and the percentage of hydrogen bonding was reduced. T26 polyurea has realized the protection effect of zero fragmentation of large-equivalent contact explosion, which has a high application value for blast mitigation and blast-fragmentation prevention in actual engineering.