Fracture Patterns Research Articles

The failure evolution of hydraulic asphalt concrete under different tensile fatigue loading

The fracture and damage evolution patterns of hydraulic asphalt concrete (HAC) under cyclic tensile loading determine the performance of asphalt concrete impermeable structures in embankment dams under seismic loading. Therefore, in this study, the whole fatigue tensile damage process of HAC under different loading conditions was studied with the help of acoustic emission (AE) technique. The results indicated that the fatigue behaviors of the HAC and AE signals follow the same evolutionary pattern, experiencing the initial deformation stage, the stability stage, the acceleration stage, and the failure stage. The b value, obtained from the least square fit between AE event number and magnitude, decreases to its lowest point upon specimen failure, and this decrease corresponds to a sudden increase in the peak frequency of the AE. The parametric analysis of relative amplitude-average frequency values classified for different cracking modes revealed that the tensile cracking dominates during the fatigue damage process, while the proportion of shear cracking events increases during the failure stage. Moreover, the peak value of the proportion of shear cracking events appears within the range near the point of failure, making it a useful indicator for providing critical warnings of HAC fatigue damage.

Evaluation and Management of Posterior Tibial Plateau Fractures.

Tibial plateau fractures are caused by high-energy or low-energy trauma and result in complex injuries that require careful management of both osseous injuries and associated soft tissues. The posterior aspect of the tibial plateau can be involved in a variety of fracture patterns, requiring systematic evaluation, imaging, and advanced surgical planning to address these complex injuries. Early classification systems failed to classify posterior plateau fractures; however, three-dimensional imaging and newer classification schemes, including the Quadrant System and 3D systems, have incorporated posterior column lesions. There has been a growing body of literature focused on fixation principles and plating options for posterior column fractures. Furthermore, there are multiple approaches for surgeons to choose between, including a direct posterior, posteromedial, posterolateral (including Lobenhoffer and lateral condyle osteotomy), and combined posterior approach. This article presents a guide for managing posterior tibial plateau fractures, including the initial evaluation and management, descriptions of the surgical approaches, principles of fixation, and the associated outcomes and complications.

Assessment of Reinforcement Effect of FRP-Strengthened Shield Segment Joint Based on the CZM Model

As the weakest link in the shield segment, the reinforcement and repair technology of shield segment joint has received widespread attention. In this study, an finite element model utilizing a cohesive zone model (CZM) was constructed to simulate the mechanical behavior of the shield segment joint during the whole fracture process. The proposed modeling method of joint allows multiple layers of steel bars to be stacked without interference by applying cohesive elements. Cohesive elements were employed to represent the mechanical response of potential fracture surfaces in concrete, as well as the interfaces between steel–concrete and fiber-reinforced polymer (FRP)–concrete, by utilizing various constitutive models tailored for mixed-mode loading conditions. A group of experiments was chosen to assess the precision of the proposed model by comparing the mechanical response and the fracture patterns. Finally, parameter analyses were conducted to study the reinforcement effect of the FRP bonding length and width on the shield segment joint. The results indicate that external bonding of FRP can effectively enhance the bearing capacity and stiffness of shield segment joints. However, insufficient bonding length or width may significantly reduce the strengthening effect and potentially decrease the ductility of the joint.

Influences of clean fracturing fluid viscosity and horizontal in-situ stress difference on hydraulic fracture propagation and morphology in coal seam

The viscosity of fracturing fluid and in-situ stress difference are the two important factors that affect the hydraulic fracturing pressure and propagation morphology. In this study, raw coal was used to prepare coal samples for experiments, and clean fracturing fluid samples were prepared using CTAB surfactant. A series of hydraulic fracturing tests were conducted with an in-house developed triaxial hydraulic fracturing simulator and the fracturing process was monitored with an acoustic emission instrument to analyze the influences of fracturing fluid viscosity and horizontal in-situ stress difference on coal fracture propagation. The results show that the number of branched fractures decreased, the fracture pattern became simpler, the fractures width increased obviously, and the distribution of AE event points was concentrated with the increase of the fracturing fluid viscosity or the horizontal in-situ stress difference. The acoustic emission energy decreases with the increase of fracturing fluid viscosity and increases with the increase of horizontal in situ stress difference. The low viscosity clean fracturing fluid has strong elasticity and is easy to be compressed into the tip of fractures, resulting in complex fractures. The high viscosity clean fracturing fluids are the opposite. Our experimental results provide a reference and scientific basis for the design and optimization of field hydraulic fracturing parameters.

Pediatric Facial Fractures: Demographics, Injury Patterns, and Associated Injuries in 3334 Patients.

Pediatric craniofacial fractures are fundamentally distinct from their adult counterparts because of unique injury patterns and effects on future growth. Understanding patterns and injury context informs management and risk mitigation. Previous studies include only inpatients, operative patients, or are specialty-specific. In contrast, our study presents a comprehensive assessment of all pediatric facial fracture patients seen at a single institution. Patients under 18 years old who were evaluated for facial fractures at a level I pediatric trauma center between 2006 and 2021 were reviewed. Subanalysis was performed for groups defined by age. Variables studied included demographics, etiology, fracture pattern, associated injuries, management, and outcomes. Three thousand thirty-four patients were included. Mean age at presentation was 11.5 to 4.9 years. The majority were Caucasian (82.6%) and male (68.4%). Sports were the leading cause of injury in older patients (42.2% of patients over 12y), compared with activities of daily living in patients under 6 years (45.5%). Thirty-two percent of patients were hospitalized, 6.0% required ICU care, and 48.4% required surgery. Frequency of ICU admission decreased with age (P<0.001), whereas operative intervention increased with age (P<0.001). Zygomaticomaxillary complex (P=0.002) and nasal fractures (P<0.001) were common in older patients, whereas younger patients experienced more skull (P<0.001) and orbital fractures (P<0.001). The most associated injuries were soft tissue (55.7%) and neurologic (23.6%). This large-scale study provides updated characterization of craniofacial fractures in the pediatric population, providing a necessary framework for future studies on outcomes assessments and preventative care.

Associated Factor and Long-Term Clinical Outcomes for Patients with Postoperative Rotational Malreduction in Pediatric Supracondylar Humeral Fractures

Background and Objectives: Long-term outcomes of immediately postoperative rotational malreduction in the axial plane after operative treatment of supracondylar humeral fractures (SCHF) are unknown. This study aimed to investigate the long-term clinical outcomes and associated factors for immediately postoperative rotational malreduction of SCHF. Materials and methods: In this retrospective case–control study, 88 patients who underwent surgery for Gratland type III SCHF were enrolled between January 2012 and January 2020. Among them, 49 patients had immediately postoperative malrotational reduction (rotational malreduction group) and 39 patients had no rotational deformity (control group). To evaluate the associated factors for immediately postoperative rotational malreduction, demographic data, fracture patterns, physical examination signs, and preoperative radiological parameters were analyzed. To compare the clinical outcomes, operation time, range of motion of the elbow, time from operation to full range of motion, and Flynn criteria were evaluated. The Oxford elbow score was used to investigate long-term clinical outcomes for patients five years after operation. Results: The mean age was 5.7 ± 2.3 years and mean follow-up period was 15.7 ± 4.0 months. The rotational malreduction group had significantly more patients with oblique fracture pattern (p = 0.031) and Pucker sign (p = 0.016) and showed a significantly longer operative time (p = 0.029) than the control group. Although there was no significant difference in the range of elbow motion and the Flynn criteria, the Kaplan–Meier survival curve showed a longer time to recover the full range of elbow motion in the rotational malreduction group (p = 0.040). There were no significant differences in the long-term clinical outcomes assessed using the Oxford elbow score (p = 0.684). Conclusions: Oblique fracture pattern and Pucker sign may be associated with immediately postoperative rotational malreduction in the axial plane. Although patients with immediately postoperative rotational malreduction showed favorable results of long-term clinical outcomes, they required more weeks to recover the full range of elbow motion.

VARIABLE ANGLE LOCKING PLATE VERSUS MULTIPLE K WIRE FIXATION FOR INTRA-ARTICULAR DISTAL RADIUS FRACTURE: A PROSPECTIVE COMPARATIVE STUDY OF FUNCTIONAL OUTCOME IN ELDERLY

Distal radius fracture (DRF) is a common wrist injury and it accounts for about one-sixth of emergency department visits. In spite of availability of various treatment options, none is universally effective for comminuted intraarticular fracture, because of varied fractures patterns. Two commonly used surgical methods are multiple K-wire fixation and open reduction and internal fixation by variable angle locking plates. Objective of the study was to compare functional outcomes of variable angle locking plate and multiple K wire fixation for intra-articular distal radius fracture in elderly. Prospective observational study was conducted among the patients of distal radius fractures with age more than 50 years. Patients were divided in to two groups with 24 cases in each group. Group one included patients treated with variable angle locking plate and group two included patients treated with multiple K-wires. Post surgery patients were assessed at 6 weeks, 3, 6 and 12 months. Evaluation was done clinically, and the outcomes were assessed by using the Disabilities Arm, Shoulder and Hand (quickDASH) score (primary outcome), Patient-Rated Wrist Evaluation (PRWE) score, range of motion, grip strength and were compared between the groups. Patients treated with variable angle locking plate was found to have better functional outcome than those treated with multiple K-wire initially during the study, but later by the end of the study at 12 months, both groups were found to be having similar outcomes, with no significant difference between the groups. This signifies that among variable angle locking plate and multiple K-wire fixation, no single procedure is superior to the other in long term.

Biomechanical analysis using finite element analysis of orbital floor fractures reproduced in a realistic experimental environment with an anatomical model

Introduction: In this study, we attempted to demonstrate the actual process of orbital floor fracture visually and computationally in anatomically reconstructed structures and to investigate them using finite element analysis.Methods: A finite element model of the skull and cervical vertebrae was reconstructed from computed tomography data, and an eyeball surrounded by extraocular adipose was modeled in the orbital cavity. Three-dimensional volume mesh was generated using 173,894 of the 4-node hexahedral solid elements.Results: For the cases where the impactor hit the infraorbital foramen, buckling occurred at the orbital bone as a result of the compressive force, and the von Mises stress exceeded 150 MPa. The range of stress components included inferior orbital rim and orbital floor. For the cases where the impactor hit the eyeball first, the orbital bone experienced less stress and the range of stress components limited in orbital floor. The critical speeds for blowout fracture were 4 m/s and 6 m/s for buckling and hydraulic mechanism.Conclusion: Each mechanism has its own fracture inducing energy and its transmission process, type of force causing the fracture, and fracture pattern. It is possible to determine the mechanism of the fracture based on whether an orbital rim fracture is present.

Effect of Long Glass Fiber Orientations or a Short-Fiber-Reinforced Composite on the Fracture Resistance of Endodontically Treated Premolars.

This study aimed to evaluate the effect of direct restorations using unidirectional glass fiber orientations and a short-fiber-reinforced composite (SFRC) on the fracture resistance of endodontically treated premolars with mesio-occluso-distal cavities. Ninety double-rooted premolars were selected. Fifteen teeth were left intact/as a control group. The endodontic treatment and cavity preparations of seventy-five teeth were performed and divided into five experimental groups: Resin composite (RC), modified transfixed technique + RC, circumferential technique + RC, cavity floor technique + RC, and SFRC + RC. All teeth were fractured under oblique static loading at a 30° angle using a universal testing machine. The fracture patterns were observed and classified. Data were analyzed with one-way analysis of variance, Pearson chi-square, and Tukey HSD post hoc tests (p = 0.05). The highest fracture strength values were obtained in intact teeth (599.336 N), followed by modified transfixed + RC treated teeth (496.58 N), SFRC + RC treated teeth (469.62 N), RC (443.51 N), circumferential + RC treated teeth (442.835 N), and cavity floor + RC treated teeth (404.623 N) (p < 0.05). There was no significant difference between the RC and the circumferential technique + RC (p > 0.05). Unrepairable fractures were observed at low rates (20%) in the modified transfixed + RC and SFRC + RC teeth, and at higher rates in RC (73.3%), cavity floor + RC (60%), and circumferential + RC (80%) teeth. The application of an SFRC or the modified transfixed technique yielded an improved fracture strength and the fracture pattern of ETPs being restored with a universal injectable composite.

Ankle fracture surgery performed by orthopaedic residents without supervision has comparable outcomes to surgery performed by fellowship trained orthopaedic surgeons.

Unstable fractures often necessitate open reduction and internal fixation (ORIF), which generally yield favourable outcomes. However, the impact of surgical trainee autonomy on healthcare quality in these procedures remains uncertain. We hypothesized that surgery performed solely by residents, without supervision or participation of an attending surgeon, can provide similar outcomes to surgery performed by trauma or foot and ankle fellowship-trained orthopaedic surgeons. A single-center cohort of an academic level-1 trauma center was retrospectively reviewed for all ankle ORIF between 2015 and 2019. Data were compared between surgery performed solely by post-graduate-year 4 to 6 residents, and surgery performed by trauma or foot and ankle fellowship-trained surgeons. Demographics, surgical parameters, preoperative and postoperative radiographs, and primary (mortality, complications, and revision surgery) and secondary outcome variables were collected and analyzed. Univariate analysis was performed to evaluate outcomes. A total of 460 ankle fractures were included in the study. Nonoperative cases and cases operated by senior orthopaedic surgeons who are not trauma or foot and ankle fellowship-trained orthopaedic surgeons were excluded. The average follow-up time was 58.4 months (SD ± 12.5). Univariate analysis of outcomes demonstrated no significant difference between residents and attendings in complications and reoperations rate (p = 0.690, p = 0.388). Sub-analysis by fracture pattern (Lauge-Hansen classification) and the number of malleoli involved and fixated demonstrated similar outcomes. surgery time was significantly longer in the resident group (p < 0.001). The current study demonstrates that ankle fracture surgery can be performed by trained orthopaedic surgery residents, with similar results and complication rates as surgery performed by fellowship-trained attendings. These findings provide valuable insights into surgical autonomy in residency and its role in modern clinical training and surgical education. Level III - retrospective cohort study.

Simulative investigation of the required level of geometrical individualization of the lumbar spines to predict fractures.

Injury mechanisms of the lumbar spine under dynamic loading are dependent on spine curvature and anatomical variation. Impact simulation with finite element (FE) models can assist the reconstruction and prediction of injuries. The objective of this study was to determine which level of individualization of a baseline FE lumbar spine model is necessary to replicate experimental responses and fracture locations in a dynamic experiment.Experimental X-rays from 26 dynamic drop tower tests were used to create three configurations of a lumbar spine model (T12 to L5): baseline, with aligned vertebrae (positioned), and with aligned and morphed vertebrae (morphed). Each model was simulated with the corresponding loading and boundary conditions from dynamic lumbar spine experiments. Force, moment, and kinematic responses were compared to the experimental data. Cosine similarity was computed to assess how well simulation responses match the experimental data. The pressure distribution within the vertebrae was used to compare fracture risk and fracture location between the different models.The positioned models replicated the injured spinal level and the fracture patterns quite well, though the morphed models provided slightly more accuracy. However, for impact reconstruction or injury prediction, the authors recommend pure positioning for whole-body models, as the gain in accuracy was relatively small, while the morphing modifications of the model require considerably higher efforts. These results improve the understanding of the application of human body models to investigate lumbar injury mechanisms with FE models.

PROPOSAL OF A MODIFIED TIP APEX DISTANCE FOR PREDICTION OF LAG SCREW CUT-OUT IN TROCHANTERIC HIP FRACTURES

Lag screw cut-out is a serious complication of dynamic hip screw fixation in trochanteric hip fractures. Lag screw position is recognised as a crucial factor influencing the occurrence of lag screw cut-out. We propose a modification of the Tip Apex Distance (TAD) and hypothesize that it could enhance the reliability of predicting lag screw cut-out in these injuries.A retrospective study of hip fracture cases was conducted from January 2018 to July 2022. A total of 109 patients were eligible for the final analysis. The modified TAD was measured in millimetres, based on the sum of the traditional TAD in the lateral view and the net value of two distances in the anteroposterior (AP) view. The first distance is from the lag screw tip to the opposite point on the femoral head along the lag screw axis, while the second distance is from that point to the femoral head apex. The first distance is a positive value, whereas the second distance is positive if the lag screw is superior and negative if it is inferior. Receiver operating characteristic (ROC) curve analysis was used to assess the reliability of various parameters for evaluating the lag screw position within the femoral head.Factors such as reduction quality, fracture pattern according to the AO/OTA classification, TAD, Calcar-Referenced TAD, Axis Blade Angle, Parker’s ratio in the AP view, Cleveland Zone 1, and modified TAD were statistically associated with lag screw cut-out. Among the tested parameters, the novel parameter exhibited 90.1% sensitivity and 90.9% specificity for predicting lag screw cut-out at a cut-off value of 25 mm, with a p-value &lt; 0.001.The modified TAD demonstrated the highest reliability in predicting lag screw cut-out. A value of 25 mm may potentially reduce the risk of lag screw cut-out in trochanteric hip fractures.

Low avascular necrosis rates in femoral neck fractures: efficacy of cannulated screw fixation.

Cannulated screw fixation for femoral neck fractures is often limited by concerns of avascular necrosis (AVN) occurring, historically seen in 5-40% of fixed intracapsular fractures. This study aims to assess the outcomes, particularly the AVN rate, associated with current surgical techniques within our unit. We conducted a single-center cross-sectional study, manually searching operative records between July 14, 2014, and December 1, 2018, identifying patients with intracapsular fractured neck of femur fixed with cannulated screws, with a minimum of two years follow-up. Patient records and radiographs were reviewed for clinical and radiographic diagnoses of AVN, non-union, post-operative metalwork infection, and screw penetration of the head. Additionally, fracture pattern and displacement, screw configuration, reduction techniques, and adequacy of reduction were recorded, with radiographs independently analyzed by four orthopedic surgeons. Fifty-six patients were included; average age of 67 years (range 30-100). Forty-two patients (75%) sustained displaced fractures and 14 patients (25%) had undisplaced fractures. Two (4%) patients developed AVN, with no cases of non-union, post-operative metalwork infection or screw penetration of the head. Eight patients (14%) sustained a high-energy injury, though none of these patients developed AVN. All fractures required closed reduction; no open reductions performed. Twenty-seven (64%) of reductions were adequate. Our observed AVN rate is notably lower than the widely reported figures, even among a significant proportion of displaced fractures that were fixed. This study underscores that with adequate fixation, cannulated screws represent an excellent option for treating intracapsular neck of femur fractures, even in cases of displaced fracture patterns with imperfect reduction.

Investigation of fracture patterns and effect on capacity in all-solid-state batteries based on peridynamic electro-chemo-mechanical model

The evolution of complex fracture patterns of composite electrodes in all-solid-state batteries (ASSBs) during electrochemical cycles is one of the main phenomena driving capacity degradation. Such fracture patterns in active materials usually involve cracks with various orientations. While conventional wisdom usually treats fracture as ultimate failure of materials in many scenarios, the effect of crack in batteries is worth further investigation. Here, a concurrently coupled electro-chemo-mechanical model based on peridynamics has been developed to study fracture patterns and electrochemical performances of composite anodes during processes of charge and discharge. The framework consists of a classic bond-based peridynamic mechanical model, an electrochemical model, and a coupling technique to reflect the interaction between them in a bidirectional manner. The bond-based peridynamic mechanical model considers the active material’s elastic–plastic deformation and the solid electrolyte’s elastic deformation. The fracture energies of the active material, the solid electrolyte, and the interface are also incorporated into this model. The electrochemical model considers the volume expansion of the active material caused by the intercalation of lithium ions and the Butler-Volmer relation of charge transfer on the interface. Various parametric analyses are performed using this modeling framework to investigate the effects of external pressure, fracture energies of active material and solid electrolyte, and Young’s modulus on fracture patterns and electrochemical performances. It is found that different material parameters result in distinct fracture patterns in the active material with radial cracks or circumferential cracks, thus profoundly affecting the rates of charge and discharge. This work demonstrates the importance of considering the complex fracture patterns in electrode materials of batteries and provides insights for selecting more suitable electrode materials to mitigate capacity degradation.

Distinct patterns of fracture propagation in distal radial fractures and the relationship to the ulnar head

BackgroundThe aim was to assess the direction of distal radius fractures and their relationship to the ulnar head. MethodsWe reviewed the 160 wrist radiographs. The fracture line was measured on the postero-anterior and lateral radiographs relative to the long axis of the forearm and the relationship to the ulnar head. FindingsPA radiographs: the fracture line ran distal ulnar to proximal radial (ulnar to radial) in 11%, transverse in 74% and distal radial to proximal ulnar (radial to ulnar) in 16%. Lateral radiographs: the fracture line ran distal volar to proximal dorsal in 88%, transverse in two 1% and dorsal to volar in 11%. Radial shift (7.5%) only occurred with ulnar to radial or transverse fractures.The ulnar to radial fracture line started at the proximal end of the ulnar head/distal radio-ulnar joint in 88%. The radial to ulnar fracture line started ended a mean of 2.5 mm proximal to the distal radio-ulnar joint (p < 0.01). The transverse fracture line started at the base of the distal radio-ulnar joint in 53% and proximally in 47%. InterpretationThere are two distinct coronal patterns: radial to ulnar ending c. 2 mm proximal to the distal radio-ulnar joint; ulnar to radial starting at the proximal distal radio-ulnar joint. There may be third pattern - transverse fractures; these may be variants of the above. Sagittally the main direction is volar to dorsal but 11% are obverse.This is the first description of distinct fracture patterns in extra-articular distal radius fractures. In addition the fracture patterns appear to correlate with different directions of force transmission which fit with our understanding of falling and the relatively uncontrolled impact of the wrist/hand with the ground.These patterns of fracture propagation help understand how the biomechanics of wrist fractures and may enable prediction of collapse.

Which radial head fractures are best treated surgically?

Despite the common occurrence of radial head fractures, there is still a lack of consensus on which radial head fractures should be treated surgically. The radial head is an important secondary stabilizer in almost all directions. An insufficient radial head can lead to increased instability in varus-valgus and posterolateral rotatory directions, especially in a ligament-deficient elbow. The decision to perform surgery is often not dictated by the fracture pattern alone but also by the presence of associated injury. Comminution of the radial head and complete loss of cortical contact of at least one fracture fragment are associated with a high occurrence of associated injuries. Nondisplaced and minimally displaced radial head fractures can be treated non-operatively with early mobilization. Displacement (>2 mm) of fragments in radial head fractures without a mechanical block to pronation/supination is not a clear indication for surgery. Mechanical block to pronation/supination and comminution of the fracture are indications for surgery. The following paper reviews the current literature and provides state-of-the-art guidance on which radial head fractures should be treated surgically.

Structural geology of El Peñón karst system along an anticlinorium of the Northern Andes, Colombia

Structural control is one of the most important factors in developing the karstic system since the fractures facilitate the infiltration and circulation of groundwater. This accelerates the mineral dissolution processes responsible for the formation of endo and exokarstic geomorphological features, such as sinkholes and underground cavities, among other landforms that characterize this environment. This study provides information on the structural geology of the El Peñón karstic system, considered one of the most significant and extensive karstic regions in Colombia. The karst is tectonically controlled by joints with a preferential NW-SE orientation and cleavage planes with an NE-SW trend, guiding the development of drainage systems, closed depressions, and underground cavities. The stress tensor obtained with a NW-SE direction (127°) explains the deformation in the area and its influence on the development of the karstic system. It was also established that the potential groundwater flow occurs through open fractures with a direction of 120°-130° (parallel to the stress tensor) and along the cleavage planes (40°-50°). The fracture patterns are characterized by intermediate intensity values, predominantly low fracture density, minimal lengths, and good connectivity between fracture planes.

Effects of solution treatments on the microstructure and mechanical properties of Inconel 625 fabricated by electron beam freeform fabrication

The present study investigated the effects of solution treatments on the microstructure and mechanical properties of Inconel 625 fabricated by electron beam freeform fabrication. The results indicated that the microstructure of the as-deposited specimen exhibited typical dendritic characteristics. Meanwhile, the Laves ((Ni,Fe,Cr)2(Nb,Mo,Ti)) phases and needle-shaped δ phases precipitated. The deposition process led to the development of a preferred orientation feature along the building direction, and the typical {001}<100> plate texture was observed. Solution treatments at 900 °C and 1000 °C resulted in the precipitation of more δ phases, and the volume fraction was approximately 5.29% and 7.96%, respectively. The precipitated phases fully dissolved at solution temperatures of 1100 °C and 1200 °C, and equiaxed grains with a twin substructure were formed. The recrystallization weakened the preferred orientation, leading to a decrease in grain size and the formation of {111}<1-10> texture. The as-deposited specimen exhibited an ultimate tensile strength (UTS) of 682 MPa, a yield strength (YS) of 410 MPa, and an elongation of 56.4%. Solution treatment had minimal impact on the UTS, and the YS was mainly contributed by the solid solution strengthening. However, the elongation was greatly improved at elevated solution temperatures, and the elongation was increased to 72.1% at most. The primary mode of fracture was toughness fracture, which was attributed to the coalescence of microvoids. The solution treatment at 900 °C led to a fracture pattern that exhibited a combination of toughness and brittleness, and decreased the elongation to 48.5%.

The Influence of e-glass epoxy composite laminate material application on the crack pattern of cylinder concrete column cross-section

In order to better understand the phenomenon of applying GEC reinforcement to RCC based on the percentage of surface crack pattern (PCP), this research will use e-glass epoxy composite laminate (GEC) to obtain the damage pattern of reinforced concrete column specimens (RCC) utilizing GEC. Additionally, it will compare the splitting tensile strength (STS) and SCP. In accordance with ASTM C496 guidelines, the RCC specimens used in this investigation had a cylindrical shape and measured 150 mm in length and 50 mm in diameter. GEC material, consisting of 0–4 layers of woven e-glass fiber sheets, was applied as an extra layer on top of the RCC. In compliance with ASTM C496 guidelines, a Universal Testing Machine (UTM) was used to perform the split tensile test. With the aid of Adobe Photoshop software, the Histogram approach was used to calculate the crack pattern's proportion. The study's findings demonstrated that the specimens reinforced with four layers of GEC exhibited the highest damage pattern. This suggests that the reinforced specimens must be subjected to a sizable load in order to be damaged. Hence, the damage that occurs in the specimens can be lessened by applying GEC layers on RCC. Further information about the performance of RCC reinforced with GEC is also provided by a comparison of the splitting tensile strength and the percentage of fracture pattern

Effect of cementation on the mechanical response of sands using acoustic emission technique

This study investigates the impact of cementation on the mechanical behavior of sands with various cement content (CSR) in drained triaxial compression, employing both Acoustic Emission (AE) and Environmental Scanning Electron Microscopy (ESEM) measurements. The experimental findings, encompassing quantitative statistics of stress-strain relations, microstructure variations, and AE characteristics, demonstrate that: the addition of CSR from 1% to 20% leads to an exponential rise in peak strength and stiffness, marking a transition from ductile to brittle mechanical failure, which is pinpointed between CSR levels of 5% to 10%. AE characteristics unveil an upward-opening parabola of normalized AE hits with CSR, a clear transition zone identification, and three distinct types of AE rate evolutions corresponding to failure patterns of ductile bulging, shear banding, and brittle fracturing, respectively. It suggests an intimate correlation with the intrinsic differences in micro-mechanical behaviors and AE propagation properties of cemented sands with varying CSRs. Notably, the bulging and shear banding processes are divided by AE into three stages, whereas fracturing is characterized into five stages. Two precursory AE anomalies associated with incipient failure and complex failure modes are observed, emphasizing the advantage of using AE to reflect the internal micro-mechanical behavior of cemented sands over conventional stress-strain manifestations.