Crack Zone Research Articles

Effect of the notch depth on fracture behavior of TC4 titanium alloy sheets

To evaluate the low-stress brittle fracture of TC4 titanium alloy sheet structures, the effect of notch depth (d) on the fracture behavior of the 1.8 mm thick TC4 titanium alloy sheets was investigated combied with tensile tests and digital image correlation method. The results show that the ductile–brittle transition (DBT) occurs with increasing notch depths. Ductile fracture occurs for the notched samples with d = 0.5–1.5 mm, and a uniform plastic deformation stage is observed in the load–displacement (P-L) curves, and there are stretch zone and the stable crack propagation zone in the fracture surfaces. Brittle fracture occurs for the notched samples with d = 3.0–5.0 mm, and there is only the linear elastic stage in the P-L curves, and no stretch zone in the fracture surfaces. The samples at the middle notch depths (d = 2.0–2.5 mm) are in the transition from ductile to brittle fracture, and there exists the elastoplastic deformation stage in the P-L curves, and the stretch zone and stable crack propagation zone are both decreased. The analysis of notch fracture parameters shows that fracture of notched samples is controlled by the stress concentration and the stress field intensity of an imaginary crack with the same notch depth. The effect of crack gradually increases with increasing d, which results in increased brittle fracture tendency. Moreover, the fracture energy γf can characterize the DBT of notched TC4 titanium alloy sheets, and the γf is proportional tothe ratio of critical plastic zone size to d (rpc/d). Finally, the rpc/d is proposed to characterize the DBT of the notched TC4 titanium alloy sheets, and the criterion of the DBT for the notched TC4 titanium alloy sheets is obtained.

A Novel Continuous-Discontinuous Multi-Field Numerical Model for Rock Blasting

During blasting, rock failure is caused by blasting wave and explosive gas pressure, as a multi-field coupled process. Most numerical models focus on the effect of blasting wave where the gas pressure is commonly accounted for by empirical relations, ignoring the penetration and permeation of gas flow in cracks. This can underestimate the failure region. In this work, a novel multi-field model is developed in the framework of a continuous-discontinuous element method (CDEM), which is a coupled finite-discrete method with explicit integration strategy. The deformation and cracking of rock mass and the distribution of gas pressure are captured. The proposed method is verified by comparing the results to other results provided in published literature. Especially, by simulating the cases with blocked and unblocked blasting hole, we found that: (i) The fracture degree of the case with blocked blasting hole was 30% higher than that of the unblocked blasting hole. (ii) The radial main cracks in the fracture area are mainly caused by the explosive gas, and the tiny and dense cracks near the hole are induced by the explosion stress wave. (iii) The explosion crushing zone is mainly formed by the action of explosion stress wave, while the crack zone is formed by the combined action of the explosion stress wave and explosive gas. The proposed method provides a useful tool to properly simulate a rock blasting process.

Potentiodynamic Corrosion Behavior and Microstructural Characteristics of Pulsed CMT-Welded AA2014-T6 Aluminium Alloy Joints: Effect of PWHT

AA2014-T6 is an Al-Cu-Mg-based precipitation-hardened aluminium alloy widely used in aerospace due to its high strength to weight ratio. This alloy is joined by a pulsed cold metal transfer (PCMT) arc welding process to overcome the high heat input related problems in gas metal arc welding (GMAW) such as a coarser dendritic structure in the fusion zone (FZ), wider heat affected zone (HAZ), solidification and HAZ liquation cracking, softening in HAZ, and poor corrosion resistance of welded joints in salt environment. The joints were subjected to PWHT of artificial aging (AA), solution treatment (ST), and solution treatment + aging (STA) conditions. The corrosion rate was determined using a potentiodynamic corrosion test in a solution of 3.56 wt.% NaCl with pH values of 4, 7, and 11. Results disclosed that the PCMT joints subjected to the potentiodynamic corrosion test in NaCl solution of pH-4, pH-7, and pH-11 disclosed very low, moderate, and extremely high pitting corrosion, respectively. The corrosion resistance of ST joints was improved by 53.34%, 15%, and 15.12% in pH-4, pH-7, and pH-11 NaCl solution compared to as-welded joints. The pitting potential of ST joints is comparable to BM. The BM showed the pitting potential of −175, −450, and −550 mV in pH-4, pH-7, and pH-11 NaCl solution. The ST joints showed 75.29%, 29.16%, and 27.85% lower corrosion potential compared to STA joints in pH-4, pH-7, and pH-11 NaCl solution, respectively. The ST joints disclosed the lower pitting potential of −105, −425, and −505 mV in pH-4, pH-7, and pH-11 NaCl solution, respectively, whereas the STA joints revealed greater pitting potential of −425, −600, and −700 mV in pH-4, pH-7, and pH-11 NaCl solution, respectively. The superior corrosion resistance of ST joints compared to AA and STA joints is attributed to the dissolution of precipitates in Al solid solution resulting in a lower potential difference in FZ. This minimizes the preferential sites for pitting corrosion to occur.

Reasons for formation of transverse cracks in longitudinal weld of a pipe of the main gas pipeline

Investigations of transverse cracks in a longitudinal weld of a main gas pipeline pipe are presented, and the reasons for the formation of defects are analyzed. A comparative analysis of the results of in-line diagnostics and additional non-destructive testing with the actual parameters of cracks in microsections was carried out. The microhardness of the weld metal was measured in the crack zone and at a distance of up to 20 mm from it in both directions, which showed the presence of residual stresses in the region of the crack tip. The methods of optical and electron scanning microscopy were used to study the crack zone with the determination of the chemical composition of the weld base metal and inclusions in the crack zone. The results obtained made it possible to classify defects as “cold cracks” that formed in the weld metal after a long period of operation and developed further according to the stress corrosion cracking mechanism.

Surface modification of IN713 LC superalloy with Metco 204NS by laser surface alloying

Ceramics are one of the best engineering materials for coating gas turbine blades. In this study, the Metco204NS ceramic coating (Zr2O + 8%Y2O3) was applied by the laser surface alloying (LSA) method on IN713 LC nickel-based superalloy. To influence the heat input on the structure of the ceramic coating and its substrate, and as well as the rejuvenated zone (RZ), different variables were used in LSA. The results showed that with an increase in heat input by the laser, the sensitivity to liquation cracks in the heat affected zone and solidification cracks in the RZ decreases. The most important reason for this was the increase in backfilling by the molten metal due to its high fluidity. However, with increasing heat input, the hardness increased due to the reduction of the distance between the dendrites. Solidification rate (R) and temperature gradient (G) were identified as the most important microstructure controlling factors in the RZ. So, with increasing the heat input and thus decreasing G and R, the tendency of the structure to change from cellular to columnar and then equiaxed increased. The uniform and homogeneous coating of Metco 204NS significantly increased the wear resistance of IN713 LC superalloy. The higher hardness and wear resistance of melted Metco 204NS coating material relative to the RZ and the base metal was due to the presence of very hard Zr2O and Y2O3 particles in Metco 204NS and the reduction of grain size.

Research on shear behavior and resistance of UHPFRC-RC composite beam

Ultra-high performance fiber reinforced concrete (UHPFRC) is a material with high strength, ductility and impermeability, and it can be applied for strengthening concrete structure to form UHPFRC-RC composite structure. To study the shear mechanism of composite beams and establish calculation formula for shear resistance. At first, the shear test including one reinforced concrete(RC) beam and four UHPFRC-RC composite beams was designed to study the influence of UHPFRC layer, longitudinal reinforcement and shear span-to-depth ratio on shear resistance. Then, the test was conducted in three-point loading mode and the results showed that both UHPFRC layer and longitudinal reinforcement can effectively increase the shear resistance, and UHPFRC layer can improve the overall ductility of the structure. As for the local part, such as interface and UHPFRC layer, the near interface cracking(NIC) zone appeared in the concrete element and UHPFRC layer appeared plastic hinges in the failure stage, they were special aspects for composite beams. Furthermore, the strain condition of reinforcement was recorded and the corresponding failure mechanism was analyzed in this paper. Finally, the calculation formula was established based on the truss-arch model and above works, and to verify this model, the test results from this paper and literatures were adopted to calculate the prediction values and compare them with test values, the results proved the calculation formula can predict shear resistance of UHPFRC-RC composite beams accurately.

Experimental investigation on the properties of the interface between RCC layers subjected to early-age frost damage

This research presents the macroscopic and microscopic performance of the early-age frost roller compacted concrete (RCC) interface to investigate the influence of pre-curing time and interval time on the performance of the RCC interface subjected to early-age frost damage. Therefore, several RCC specimens were developed under different pre-curing times (12 h, 24 h, 48 h, 72 h and 7 d) and different interval times (4, 12 and 24 h). The shear failure modes, shear strength, pore structure, interfacial transition zone crack width (Wc) and hydration products of the RCC interface were evaluated. Results reveal that the shear strength of early-age frost RCC interface increases with the increase in pre-curing time and decreases with the increase in interval time. In particular, the decrease in shear strength of the early-age frost RCC interface is the most critical after the final setting. The decrease in shear strength between the initial setting and the final setting follows. Moreover, the decrease in shear strength before the initial setting is minimal. The relationship between the macroscopic and microscopic performances of the RCC interface that suffered early-age frost damage was established: the shear strength increases with the decrease in porosity and Wc. Hydrostatic pressure increases are the leading cause of damage in the early-age frost RCC interface. Moreover, the early-age frost RCC interface exhibits higher porosity and Wc and fewer hydration products than the unfrozen RCC interface. Finally, a shear strength of early-age frost RCC was proposed based on the experimental results.

The cohesive zone crack analogue for fretting fatigue based on mild wear

Fretting fatigue is an important problem that plagues many mechanical components that are in contact under vibrational loading. Life assessment of fretting fatigue cracking is important, with the damage initiation being difficult to estimate. This work extends a well-known fretting fatigue model, the crack analogue model that examines fretting induced by complete contacts or by adhering incomplete contacts of metallic surfaces. This is done by introducing cohesive zones at the contact edges. These zones address several issues related to friction and wear, by combining them in the case of mild wear where asperity plastic shearing is the dominant inelastic mechanism. Thus, the micromechanical behaviour of the surface topology is naturally introduced into the analysis. The surface roughness becomes an internal variable that evolves with the cyclic loading. The work of friction dissipates the mechanical energy and at the same time becomes the precursor of large scale wear. A predictive methodology for fretting crack nucleation is proposed through a novel cohesive model that incorporates friction and mild wear, lifting much pathology encountered by simple friction models at high normal loads.

Theoretical Study of Surrounding Rock Loose Zone Scope Based on Stress Transfer and Work–Energy Relationship Theory

In view of the actual gap between the theoretical solution and the measured value of the range of the surrounding rock loose zone excavated by blasting, the formation process and influencing factors of the surrounding rock loose zone after blasting are analyzed by combining theoretical analysis, numerical simulation, and field tests. It is proposed that the formation of the surrounding rock loose zone can be divided into two parts: the stress loose zone formed by in situ stress release after chamber excavation and the blasting–expansion loose zone formed by blasting, corresponding to the stress loose zone crack propagation. In this paper, the stress method and work–energy relationship method based on the Fenner solution were used to study the range of the surrounding rock loose zone formed after chamber excavation. A theoretical formula for determining the range of the surrounding rock loose zone is presented. These methods can clearly explain the formation mechanism of the loose zone, and the parameter selection method is simple and fast, which can be used for the theoretical prediction of the loose zone of surrounding rock in tunnel engineering in rock areas. Finally, the two methods were used to calculate the range of surrounding rock loose zone under three different working conditions in the Qingdao Metro single-track section, and the results were compared with the field monitoring results to verify the applicability of the proposed methods.

Enhanced resistance to gas tungsten arc weld heat-affected zone cracking in a newly developed Co-based superalloy

The occurrence of heat-affected zone (HAZ) cracking and the effect of pre-weld microstructural modifications on HAZ cracking susceptibility of newly developed cobalt-based superalloy welded by gas tungsten arc welding (GTAW) process is investigated. Microstructural examination shows that a primary cause of HAZ cracking is the sub-solidus liquation of MC-type carbide and γ′ precipitates, which are identified by transmission electron microscopy (TEM) as present in the material before the welding process. Total crack length (TCL) analysis on pre-weld heat-treated samples reveals that pre-weld hardness does not control the HAZ cracking susceptibility during welding. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) coupled with HAZ TCL analysis confirms that grain boundary (GB) elemental segregation of Boron (B) controls the cracking susceptibility during welding. In addition, it is observed that reduction in grain size aids the alloy's resistance to HAZ cracking. Accordingly, a new pre-weld heat treatment that couples reduction in GB segregation of B with small grain size, is found to effectively suppress the HAZ cracking not only after welding, but also after post-weld heat treatment (PWHT). Furthermore, the new pre-weld heat treatment produces tensile properties, after PWHT, that are comparable to those of the alloy without the welding operation, which demonstrates that the pre-weld heat treatment prevents the deleterious effects of welding on tensile properties of the new superalloy.

Quasi-static test of the lattice-type railway bridge pier with replaceable connection component

Replaceable components are beneficial to functionality rapid restoration of structures after earthquakes, which is a good option for seismic design of resilient bridges. In this study, a lattice-type bridge pier with replaceable connection component was proposed for railway bridges. Large initial stiffness was provided by using steel truss connection system as replaceable connection component between two concrete columns. A 1/12-scaled bridge pier model was designed and fabricated to investigate its cyclic responses by quasi-static testing. It was proved that the replaceable connection component can be easily assembled between concrete columns and work well together with them. During testing, cracks occurred at the concrete columns and crack zone extended with the increase of loading displacement. At the later loading stage, some of steel rods of the connection component between the concrete columns began to yield, the hysteretic loop of the bridge pier showed obvious pinching effect. However, concrete columns were prevented to be severely damaged due to the sacrifice of replaceable connection components. There were differences in the strain distribution of the replaceable connection component and not all the replaceable components yielded during testing. Thus, steel rods with varied strength should be used in replaceable components for the lattice-type railway bridge pier. Otherwise, it should balance the stiffness and ductile in seismic design for the lattice-type railway bridge pier with replaceable connection component.

Impact of stress concentration on reliability of metal structure elements of gantry cranes

Purpose. Analyzing the stress distribution in the metal structure of the gantry crane under the cyclic operation mode and identifying stress concentrators in the crane column to assess the survivability of the machine. Methodology. In order to achieve the objective, the methods employed included analytical calculation method, finite element method, as well as differential and integral calculus methods. To study the state of the metal structure of the gantry crane, namely the column, the program Solid Works and its application Simulation were used. Findings. Using the CAD/CAE-system, the loaded condition of the metal structure of the gantry crane was modeled and the maximum working loads were determined, and a calculated scheme of their operation was constructed. The method is presented for calculation of survivability of load-bearing elements of the crane taking into account coefficients of intensity and concentration of stresses which allow defining speed of growth of cracks in dangerous stress zones of a metal structure. Originality. The existing methods for designing crane metal structures gained their traction. The integrated technique for assessing crane reliability has been suggested for the first time. This technique is focused on estimating the survivability of components elements. For the first time solid-state models of the crane and its column have been developed; the analysis of the stress-strain state of the column was performed, maximum stresses were determined, stress concentration points in the metal structure of the column were identified and recommendations for improvement of stress zones were presented. Practical value. The presented method for assessing the reliability of metal structures of gantry cranes can be implemented in the practice of design organizations for the development, design of new gantry cranes and modernization of existing ones. The obtained results provide an opportunity to assess the accumulated damage in the elements of the metal structure, to predict the development of defects to a critical size, as well as to decide on the further operability of a gantry crane.

Assessment of the Integrity of Reinforced Concrete Beams Strengthened With Carbon Fibre Reinforced Polymer Using the Acoustic Emission Technique

Today, the use of a non-destructive technique to assess the integrity of reinforced concrete structures strengthened with carbon fibre-reinforced polymer (CFRP) is becoming increasingly important. It is highly important to assess the behaviour of the structure under load. This paper presents the evaluation of a reinforced concrete beam laminated with CFRP at the soffit using the acoustic emission technique. Two types of beams were made, a normal reinforced concrete beam and a reinforced concrete beam laminated with CFRP. CFRP was used to reinforce the bottom part of the beam. The beams were subjected to three-point loading and loaded to failure. During the loading tests, the integrity of the beams was monitored using the acoustic emission technique, and the crack patterns were observed visually. The intensity analysis was carried out on two sensors, designated as CH6 and CH7. CH6 and CH7 were located on top of the beam. Based on the intensity analysis of the acoustic emissions, five intensity crack zones were identified, namely zone A-no crack, zone B-minor, zone C-intermediate, zone D-follow up and zone E-major. With increasing load, which tended to progress the crack modes in the beam, the plots in the intensity zones developed for each crack mode from zone A to zone E. The crack progression matched well with the plots in the intensity zones. Using the intensity zones enables the early detection and prediction of damage.

Crack propagation law at the interface of FRP wrapped coal-backfilling composite structure

The coal-backfilling (CB) composite structure jointly bears the excessive stress. The interface between the coal pillar and backfilling is the weakest area. The instability of the interface can induce the splitting failure of the composite structure, and fibre-reinforced polymer (FRP) could be applied to solve this problem. The Brazilian splitting laboratory tests were carried out on the CB composite specimens and FRP wrapped CB composite specimens (WCB) with different interface angles (α = 0°, 15°, 30°, 45°, 60°, 75°, 90°). The failure modes of the above specimens were monitored by using the digital image correlation (DIC) technology. The stress intensity factors (SIFs) and the energy release rates (ERRs) at the interface centre of the composite specimens were calculated. The result shows that three types of failures, namely interfacial crack, tensile crack, and concentrated failure zone, appeared on the composite specimen. The interface angle was an important factor affecting the failure modes of the composite specimens. Interfacial stability of composite specimens could be enhanced by FRP wrapping. The SIFs KI and KII increased, and the expansion of the interface cracks was hindered by FRP wrapping. The critical load in the stable stage and the ERR of specimens were improved by FRP wrapping.

The studies of the Svalbard glacial surfaces albedo by an unmanned aerial vehicle.

Experiments related to the use of unmanned aerial vehicle (UAV) for assessing the albedo of Svalbard glaciers is described. Study area - Esmark Glacier (Isfjord Bay) and Aldegonda Glacier (Greenfjord Bay). The main purpose of the experiments is to estimate the surface albedo in the zone of the edge cracks of the outlet glacier (Esmark), where standard ground-based observations are impossible due to safety conditions, as well as to obtain spatial albedo estimates (Aldegonda) when satellite data cannot be used (overcast). The UAV (DJI Phantom 4 Pro) was retrofitted with a sensor that measures reflected solar radiation. The data on the incoming solar radiation at the surface level, measured by a similar sensor, were used to calculate the albedo. The albedo measurements were carried out along several profiles across the Aldegonda Glacier and along one profile above the Esmark Glacier, which was laid from a flat plateau (ice dome) through a zone of cracks to the open water surface of the fiord. For the first time, estimates of the surface albedo of the outlet glacier in the zone of edge cracks were obtained. Ground-based verification observations carried out on the Aldegonda glacier confirmed the results obtained by the UAV.

Three-dimensional corrosion propagation in steel rebars of RC columns with early-age cracks

• Research developed a numerical framework incorporating finite element analysis (FEA) and random processes to simulate chloride-induced corrosion and rust formation in reinforcing steel embedded in RC members having early-age cracks. • The multiphysics phenomena of corrosion initiation and propagation are modelled through adequate considerations of chloride diffusion through cracked concrete, heat and moisture transport, polarization of steel rebars, and rust formation. • FEA of a RC column with randomly distributed vertical, horizontal and inclined early-age cracks shows lower corrosion initiation times of steel rebars in the vicinity of cracks and time-evolution of corrosion pit along the length and periphery of rebars. • Research outcome signifies the strong influences of early-age cracks in induction and propagation of pitting corrosion in RC members. This paper presents numerical simulation of chloride-induced corrosion and rust formation on steel rebars embedded in RC members with early-age surface cracks. A finite element analysis (FEA) framework, which integrates physiochemical and electrochemical processes of rebar corrosion with random generation of early-age cracks, is adopted to predict temporal progression of corrosion pit along the length and periphery of rebars. The multiphysics phenomena of corrosion initiation and propagation are modelled through adequate considerations of chloride diffusion through cracked concrete, heat and moisture transport, polarization of steel rebars, and rust formation. FEA of a RC column with randomly distributed vertical, horizontal and inclined early-age cracks shows lower depassivation times (i.e., corrosion initiation times) of steel rebars in the vicinity of cracks. This results in higher reduction of rebar diameter at crack zones in comparison with that observed at distant locations from cracks where uniform corrosion of rebars prevails. Based on the observed trajectories of time-evolving rust formation along the length of rebars, for different crack patterns, an average pitting length of 140 mm is observed. Research outcome signifies the strong influences of early-age cracks in induction and propagation of pitting corrosion in RC members.

Structural Analysis of Continuous I Beam of Steel with Crack Using Finite Element Simulation

The statically indeterminate beam that is supported by three or more supports and at least one support that develops a reaction along the beam axis is known as a continuous beam. This type of beam is used in a large variety of structures as they show better resistance to seismic loads and lower deformity. However, due to the decay of steel or the increase of stresses, sometimes surface or sub-surface fissures develop in the material which is known as cracks. Because of the cracks in a structure, it may be vulnerable and start to age rapidly, which will eventually lead the structure to collapse. In this study, Abaqus CAE, a widely operated commercial software is used to simulate the cracks in a continuous I beam by the Finite Element Method. The surrounding crack zone is meshed with a smaller area due to its sensitiveness. Initially, suitable steel is selected among the major types of steel by evaluating their stress-strain curve. Then a continuous I beam of that steel with crack is simulated and the effect of the crack on the stresses is analyzed. The crack is safer when it forms on the part of the structure that is over-support. The risk of failure of a structure increases with the increasing distance of the crack from support. The greater crack depth poses a greater risk to the structure on the other hand increasing crack width has less effect on the stability of the structure

Analytical Solutions for Active Lateral Earth Force

Analytical solutions are presented for the active force on a retaining wall from a single wedge of unreinforced soil, as obtained from a general Coulomb-type limit equilibrium analysis. The solutions can accommodate variable wedge geometry, pore pressure, shear-strength parameters, surcharge stress, applied loads, pseudostatic seismic coefficients, and a tension crack zone. Closed-form expressions are derived for the critical angle of the base failure plane and corresponding maximum effective normal force on the wall for a triangular soil wedge. Verification checks show exact agreement with existing analytical solutions for simplified conditions, including Coulomb and Mononobe-Okabe active earth force. A numerical example is provided to demonstrate the method for a gravity retaining wall.

Research on fracture toughness and strength of thin-walled Ti–B25 pipes using small notched beams

One of the most essential processing procedures for thin-walled titanium pipe is hot extrusion. The non-uniform distribution of microstructure along the wall thickness and pipe axis of thin-walled pipes produced with this technology, on the other hand, would affect the non-uniformity of mechanical characteristics. Although it is generally difficult to process specimens that meet the linear elastic fracture mechanics (LEFM) conditions for this thin-walled titanium alloy Ti–B25 pipe, a simple method for non-linear elastic fracture of material was used to test the yield strength σY and fracture toughness KIC of this thin-walled titanium alloy Ti–B25 pipe in this paper. Three-point bending (3-p-b) was used to test the single edge notched beam (SENB) specimens. The fracture surface of each specimen was examined using a scanning electron microscope (SEM). The discrepancy of yield strength values measured by 3-p-b test and tensile test is 0.6% when the fictitious crack zone △afic equals 2.5 mm, and the fracture toughness KIC of the Ti–B25 pipe is determined to be 83.28 MPa m0.5. This method is a simple and practical way to evaluate the fracture toughness of thin-walled pipe, and it can be used to ensure the safe design and application of titanium alloy pipe.

Critical Comparison of Phase-Field, Peridynamics, and Crack Band Model M7 in Light of Gap Test and Classical Fracture Tests

Abstract The recently conceived gap test and its simulation revealed that the fracture energy Gf (or Kc, Jcr) of concrete, plastic-hardening metals, composites, and probably most materials can change by ±100%, depending on the crack-parallel stresses σxx, σzz, and their history. Therefore, one must consider not only a finite length but also a finite width of the fracture process zone, along with its tensorial damage behavior. The data from this test, along with ten other classical tests important for fracture problems (nine on concrete, one on sandstone), are optimally fitted to evaluate the performance of the state-of-art phase-field, peridynamic, and crack band models. Thanks to its realistic boundary and crack-face conditions as well as its tensorial nature, the crack band model, combined with the microplane damage constitutive law in its latest version M7, is found to fit all data well. On the contrary, the phase-field models perform poorly. Peridynamic models (both bond based and state based) perform even worse. The recent correction in the bond-associated deformation gradient helps to improve the predictions in some experiments, but not all. This confirms the previous strictly theoretical critique (JAM 2016), which showed that peridynamics of all kinds suffers from several conceptual faults: (1) It implies a lattice microstructure; (2) its particle–skipping interactions are a fiction; (4) it ignores shear-resisted particle rotations (which are what lends the lattice discrete particle model (LDPM) its superior performance); (3) its representation of the boundaries, especially the crack and fracture process zone faces, is physically unrealistic; and (5) it cannot reproduce the transitional size effect—a quintessential characteristic of quasibrittleness. The misleading practice of “verifying” a model with only one or two simple tests matchable by many different models, or showcasing an ad hoc improvement for one type of test while ignoring misfits of others, is pointed out. In closing, the ubiquity of crack-parallel stresses in practical problems of concrete, shale, fiber composites, plastic-hardening metals, and materials on submicrometer scale is emphasized.