Fracture Test Data Research Articles

An experimental-analytical investigation of particle size effect on the mode I fracture behavior of polymer/graphene nanocomposites

Due to their outstanding specific mechanical and functional properties, the engineering use of polymer nanocomposites and their carbon composites is becoming increasingly pervasive. Current and potential applications include micro- and flexible electronics, energy storage devices, and the use as reinforcement for advanced carbon fiber composites for light-weighting of aerospace and mechanical structures, thereby reducing their fuel consumption and carbon footprint. While a large amount of data and models regarding the effect of the weight fraction of nanoplatelets on the mechanical properties of nanocomposites is currently available in the literature, an aspect often overlooked is the scaling of the fracture behavior and the related particle size effects. Not only is the lack of understanding of size effects in nanomaterials hindering the full exploitation of their properties, it is also a serious issue since the design of large nanocomposite structures or small-scale electronic components requires capturing the scaling of their mechanical properties and developing predictive capabilities. This paper aims at filling this knowledge gap by proposing a novel analytical and experimental approach to investigate particle size effects in nanocomposites at and leveraging the acquired knowledge to improve their fracture properties, from the nanoscale all the way to the macroscale. To this end, crack initiation fracture toughness data for graphene/epoxy nanocomposite are presented as a function of nanoparticle size and weight fraction and compared with model predictions using a novel analytical model based on enhanced crack-tip shielding effect due to the reduced nanoparticle size. Extensive fracture test data are presented for model calibration and model verification.

A novel unified constraint parameter based on plastic strain energy

Constraint, defined as the resistance of a component against plastic deformation, has a significant effect on the materials’ fracture toughness. A loss of constraint can mean a higher fracture toughness. The standard test geometries such as C(T) specimens are designed to have high levels of constraint thus ensuring that a lower bound toughness is measured. To get a more accurate estimate of the integrity of low constraint components, it is necessary to study an approach of quantifying the constraint level and evaluating it on failure load. Currently, widely accepted crack-tip constraint parameters are validated using specimens with uniaxial loading such as C(T) and SEN(B). However, a large number of industrial equipment experiences loading modes other than uniaxial. The multi-axiality has been considered an important effect in various standards. Load multiaxiality can cause a change in constraint thus fracture toughness. In this paper, a novel unified constraint parameter λ based on the plastic strain energy was proposed. A series of uniaxial and biaxial bending experiments made of BS1501-224 28B steel were conducted at −160℃. A large amount of previous fracture test data of C(T) and SEN(B) specimens were used to support the study. The elastic–plastic parameter Q and the unified parameters φ, Ad* were calculated as a comparison. It is shown that the newly suggested parameter λ not only can characterize the constraint of C(T) and SEN(B) specimens but is effective in characterizing the multi-axiality effect while traditional constraint parameters fail to do so.

A New Equivalent Thickness Model for Fracture Prediction on Round Rods with Elliptic Surface Cracks

An equivalent thickness model is proposed to develop the fracture prediction method for round rods with elliptic surface cracks on the basis of a constraint equivalence principle and detailed three-dimensional (3D) stress field analysis near crack fronts with various elliptical shape factors t ([Formula: see text] 0.33, 0.4, 0.5, 0.67, 1) and crack depths a ([Formula: see text] 1/3, 2/3). The equivalent thickness is a function of crack depth a, elliptical shape factor t, elliptical parameter angle [Formula: see text] and radius of the round rod R. The reported fracture test data for the 20CrMo steel round rods with various elliptic surface cracks are adopted to validate the proposed equivalent thickness model. It is found that the improved 3D fracture prediction method by introducing the equivalent thickness is more effective than the traditional two-dimensional (2D) fracture prediction method. The prediction error is reduced from 10.5% to 3.1% for given round rods with elliptic surface cracks under tensile loading in this paper.

Characterization and prediction of hygrothermally aged CFRP adhesive joint subjected to mode II load

Carbon fiber composite adhesives joints provide higher specific strength and fatigue life than traditional joints. However, carbon fiber composites and adhesives are polymeric materials that may lose their integrity in hygrothermal environment. Predicting the environmental degradation behavior of composite joints is challenging because of limited understanding of the complex failure behavior. Moreover, the experiments are time-consuming and therefore it is essential to use accelerated aging methods such as the open faced method. However, the challenge is how to incorporate the accelerated fracture test data into the fracture prediction of real joints. To address this, a methodology is presented for predicting mode II cohesive law parameters of degraded CFRP epoxy adhesive joints using a direct method, and an accelerated aging test. End notched flexure (ENF) specimens made with CFRP laminate and epoxy adhesive were used to study the mode II fracture. Accelerated and uniform aging was achieved using open-faced specimens aged at 40 °C and 82% relative humidity (RH). Fracture testing of aged open-faced specimens along with crack-tip images were used to determine the degradation in trapezoidal traction-separation law (TSL) with aging. These variations in trapezoidal TSL with aging were used to develop a 3D finite element (FE) model of a closed ENF specimen that captures the non-uniform degradation across the specimen width. The TSL parameters degraded significantly at the specimen edges compared to width center for the closed ENF specimens. Validation of the FE model with aged closed ENF joint showed good agreement.

A local approach for fracture analysis of V- notch specimens under Mode-I loading

By using the concepts of the critical stress and the critical distance by Taylor [Taylor D.,The theory of critical distances: a new perspective in fracture mechanics. Oxford, UK: Elsevier; 2007], in this study, a local approach for fracture analysis of V- notch specimens is proposed based on the linear-elastic stress field ahead of V- notch. In the local approach, the size of the critical distance is not taken to be a material constant, whereas it is assumed that the critical distances of different notches are different and are connected closely with the variation of notched geometry. By using fracture test data of V- notches made of both brittle and ductile materials from the literature, the local approach has been verified to be both simple in computation form and highly accurate. Concerning that the fracture analysis for V- notched specimens made of ductile materials can be well performed by the local stress field failure model proposed in this study, an explanation description given in this study is that, if fracture analysis for V- notched specimens made of ductile materials can be well performed by a stress-based intensity parameter, the stress-based intensity parameter can be calculated by the Linear-Elastic Analysis without the need for carrying out complex and time-consuming Elastic-Plastic analysis and in addition some experimental verifications given recently by the author are stressed.

Mechanical fracture parameters of hemp fibre reinforced cement-based composites with recycled aggregate

This paper aims to evaluate the effect of replacement of aggregate by recycled one on fracture response of selected composites. These are hemp fibre reinforced cement-based composites. Four different mixtures were prepared: in reference one, the only natural aggregate was used whereas in the other three mixtures, the natural aggregate was replaced by recycled one in the amount of 10, 25 and 50 %, respectively. All mixtures contained hemp fibres with a length of 10 mm in the dosage of 1 % by volume. In order to determine the selected mechanical fracture characteristics of the investigated composites, three-point bending fracture tests were carried out on prismatic specimens with nominal dimensions 40 × 40 × 160 mm3 provided with an initial notch. During the whole course of the testing, the loading process was governed by a constant displacement increment of 0.02 mm/min. The vertical displacement (midspan deflection) was measured using the inductive sensor mounted on a special measurement frame placed on the specimens. The fracture tests were terminated when the midspan deflection reached 0.5 mm. The mechanical fracture parameters were obtained through a direct evaluation of the fracture test data via the effective crack model and the work-of-fracture method. The paper shows that composites with a higher dosage of recycled aggregate (25 and 50 wt%) achieve similar values of mechanical fracture properties, so this replacement can be recommended.

Constraint-dependent CTOA determination for stable ductile crack growth

The crack tip opening angle (CTOA) has been used as a reliable fracture toughness to characterize stable crack growth for thin-wall structures in low-constraint conditions. Recently, it is found that CTOA can also be utilized as a robust fracture parameter to describe the arrest fracture toughness for gas transmission pipelines in ductile steels. For better understanding the concept of CTOA, this paper presents a brief review on the CTOA definitions and its test methods. And then, four CTOA models are developed for determining the CTOA toughness using conventional single edge notched bend (SENB) specimens, including the load–displacement linear fit model, the logarithmic load–displacement linear fit model, the stable tearing energy model, and the J-differentiation model. Fracture test data from SENB specimens in A285 carbon steel are employed to evaluate the proposed CTOA models. The results show that these CTOA models can determine either identical or comparable critical CTOA values for stable ductile crack growth using the SENB specimens. A constraint-corrected CTOA resistance curve and a constraint-corrected critical CTOA equation are also obtained for A285 carbon steel.

Determination of ductile fracture properties of 16MND5 steels under varying constraint levels using machine learning methods

The current paper presents a machine learning method based on artificial neural network (ANN) model for the determination of ductile fracture properties of 16MND5 bainitic forging steel with various three-dimensional (3D) constraint conditions. A series of fracture test data with clamped single edge notched tension (SENT) specimens were used for model training and test. With the comprehensive analysis of prediction accuracy and extrapolation ability, a training strategy for ANN model was proposed including an artificially divided training set and the introduction of dropout layer. The artificial division makes the experimental samples in training set reduced by 40.7%, while the dropout layer prevents ANN model from overfitting caused by reduction of training data. Moreover, the deep nonlinear relationship between geometric dimensions (H/W, B/W, a/W) and ductile fracture properties was well learned by the ANN model. The average error of prediction is less than 11%. Finally, the proposed training strategy was extended to solve the fracture behaviors under varying thermal aging duration with saving training experimental samples by 53.8%. The results showed that the comprehensive interaction of in-plane constraint, out-of-plane constraint and thermal aging on the ductile fracture behaviors are well reproduced. Due to the good prediction performance, generalization and low training cost, the proposed training strategy can make the ANN model much more helpful for the solution of ductile fracture properties of different geometric dimensions in harsh environments.

Sorting Out Where the Sand Flows During Fracturing

The message from a single chart’s data from the first full-scale hydraulic fracturing surface test is simple: Far less proppant flows out of the first clusters passed in a stage than the last ones. The likely explanation drawn from a surface test created by GEODynamics is that the momentum of those relatively large sand grains prevents them from making that turn early on, leaving a lot of sand for later stages where the slowing flow will make the turn easier. “The flow is going 45 miles an hour; sand particles have to turn in three-eighths of an inch,” said Jack Kolle, senior technical advisor at a sister company, Oil States Energy Services. He made the comment during a presentation about modeling fracturing test data to create an engineering model of proppant flows during at the recent SPE Hydraulic Fracturing Technology Conference and Exhibition (SPE 209178). When he first heard about the test results, Kolle thought he could create a model by using basic fluid mechanics concepts. After he started working on a model, though, he realized that proppant flow was more complex than expected. “It quickly became apparent we could not explain it without CFD modeling,” he said. He was referring to computational flow dynamics (CFD) which requires massive amounts of computing power to model complex flows such as the flow of air around an aircraft wing. In the past it has been used in studies that concluded that the fast-moving flow of water and sand during fracturing resulted in uneven distribution of water and sand. The model he created based on data from GEODynamic’s unique surface testing setup and subsurface fracturing analysis evolved into the company’s fracturing-flow advisor program, StageCoach. Based on a quick look at four charts in a paper about the testing, it appears that larger-grained proppant is far more likely to slip past early clusters than smaller grains, which tend to be distributed evenly among clusters. And fracturing designs that more evenly distribute the slurry among the clusters can further flatten the distribution (SPE 209141). The results favor some established trends. The industry has embraced 100 mesh proppant for fracturing and limited-entry designs which, to varying degrees, ensure more-even distribution. What constitutes limited entry has evolved. A 2019 paper on the first two rounds of testing preceded current stage designs using clusters with only one perforation per cluster, often at the top of the hole. The test work supported the rule of thumb that shooting perforations at the bottom of the casing is a bad idea. The thinking has been that a perf gun lying on the bottom of the casing and shooting at point-blank range will create a larger hole than shots made from a distance. When fracturing begins, bottom holes will take in far more of the fluid and proppant, causing rapid wear which is magnified by the force of gravity.

Pin-loaded SENT specimen for constraint-matched fracture testing of radially propagating longitudinal cracks in thin-walled pipelines

There is considerable interest in the fracture community for representative measurements of the resistance of pipe structures to fatigue crack propagation and fracture. However, to date there has been a lack of standard test methods available for the accurate fracture testing of radially propagating longitudinal flaws in thin-walled piping. A pin-loaded single edge-notched tensile (SENT) specimen was developed, denoted the CSR SENT specimen. This test geometry has been shown to reproduce the plastic constraint for longitudinal cracks in thin-walled piping, resulting in transferable fracture test data to that application beyond the conventional limits of single-parameter J-dominated fracture mechanics. The CSR SENT was simulated with finite element analysis (FEA) to yield the parameters necessary for the experimental determination of the J-integral using standard fracture test methods. The FEA results showed that the stress intensity geometry factor, F, for the CSR SENT matched literature solutions for most crack lengths, but that the CMOD-Eta factor – ηCMOD, used to calculate the plastic component of the J-integral from the applied load and crack mouth opening displacement (CMOD) – differed from literature solutions and is specimen size-dependent. The error associated with the calculation of the J-integral is estimated to be < 5% with the obtained ηCMOD, while the use of literature solutions for ηCMOD result in significant non-conservative overestimates of the experimental J-integral. It is recommended that fracture testing be limited to a specific specimen geometry associated with a FEA-derived ηCMOD solution. The crack growth correction to the J-integral measurement was also obtained, and is recommended to be derived from the ηpin (also referred to as ηLLD, derived from the load-displacement of the pin boundary), which can be used alongside the ηCMOD for experimental calculation of the J-integral in standard single-specimen fracture testing. Friction at the pin-specimen interface results in significant non-conservative bias error in the J-integral, and a rolling pin-clevis contact is recommended with a pin diameter twice that of the specimen width to mitigate pin contact plasticity and damage.

Maximum principal strain criterion for fracture in orthotropic composites under combined tensile/shear loading

A strain-based criterion is presented in this paper to investigate mixed-mode I/II fracture behavior in orthotropic materials. The maximum principal strain component, in the vicinity of a crack existing in an orthotropic medium, is formulated considering the T-stress effect as well as the singular terms. The criterion predicts the onset of mixed-mode I/II fracture when the maximum principal strain reaches its critical value. The role of T-stress, calculated for an orthotropic domain, in the mixed-mode I/II fracture toughness assessment is explored theoretically. Along with other criteria, the accuracy of the proposed criterion is evaluated by predicting the fracture test data in the literature for wood species and laminated composites. The developed criterion is shown to be superior to other criteria in predicting the onset of mixed-mode I/II fracture in orthotropic materials.

Evaluation of the effectiveness of constraint parameters Q and φ on the uniaxial and biaxial bending specimen

Constraint has a significant effect on the materials’ fracture toughness. A loss of constraint can cause a higher fracture toughness. The standard test geometries such as C(T) specimens are designed to have high levels of constraint which ensures that only a lower bound level of toughness can be measured through them. To get a more accurate fracture toughness of low constraint level components, it is necessary to study an approach of quantifying the constraint level and evaluating the apparent fracture toughness caused by the change in constraint. Currently, widely accepted crack-tip constraint parameters are validated using specimens with uniaxial loading such as C(T) and SEN(B). However, a lot of industrial equipment experiences loading modes other than uniaxial. The multi-axiality has been considered an important effect in various standards. It can cause a change in constraint and further fracture toughness. In this paper, a series of uniaxial and biaxial bending experiments with BS1501-224 28B steel were conducted at low temperature. A large amount of fracture test data of C(T) and SEN(B) specimens were collected to support the study. The effectiveness of elastic-plastic constraint parameter Q and unified constraint parameter φ for this constraint change were investigated with a series of finite element analysis data. It is found that the parameter Q and the unified parameter φ can quantify the constraint variations in C(T) and SEN(B) specimens successfully but are not effective for uniaxial and biaxial bending specimens.

Strain model and experimental study of elastic viscoplastic for crack-tip zone of X80 steel pipe

The mechanical state of the process zone at the crack-tip is one of the main factors that affect crack initiation and growth in the long-term safe operation of oil and gas pipelines. Many tests showed that the stress and strain fields in the fracture-tip process zone can be used to define the crack propagation behavior. The goal of this paper is to improve the Hutchinson, Rice, and Rosengren (HRR) model by using cubic asymptotic polynomials to describe the stress-strain field at the crack-tip, as well as to validate the model by a thorough comparison with full-scale burst test results that account for the fracture zone's mechanical properties. The asymptotic polynomial elastic viscoplastic distribution model of stress-strain displacement field at the crack-tip is developed, and the HRR method is modified reasonably. The crack propagation test of the X80 steel pipeline in the burst test site is carried out. Experimentally, the distribution of stress and strain field in the crack-tip process zone of the X80 testing pipeline is obtained, then compared with the theoretical solution. The final results showed consistency, and the elastic viscoplastic model matched well with the running fracture test data for the X80 gas pipeline. Besides, the stress and strain fields distribution in the crack-tip process zone is verified through the full-scale test of the X80 steel pipeline, which provides a theoretical basis for the integrity evaluation of the steel pipeline.

Thermoplastic cohesive fracturing model of thermally-treated granite

Thermoplastic fracturing is a prominent characteristic of thermally-treated granite for temperature-dependent underground geotechnical engineerings , such as geothermal energy exploration and high-level nuclear waste disposal. More specifically, the tension-open of the cohesive crack in the fracture process zone (FPZ) presents a plastic softening feature dependent on temperature. However, understanding granite thermoplastic fracturing remains challenging. This work proposes a thermoplastic cohesive fracturing model of thermally-treated granite, incorporating temperature-dependent softening rule and completely coupled stress-strain-temperature constitutive relation. Several new thermoplastic fracturing properties in the proposed model are determined by further analyses of published fracturing test data (Miao et al., 2020) done on Beishan granite suffering high-temperature treatments (200–500 °C). The initial yield parameter (cohesive tensile strength) decreases linearly with the rising high-temperature treatments. The critical yield parameter (the critical crack opening displacement (COD)) follows a two-stage linear increasing rule with 300 °C as a boundary, similar to the temperature-dependent FPZ length. The plastic modulus, delineating the cohesive crack's softening rule, increases quadratically with the enhanced high-temperature treatment. The temperature sensitivity modulus ( T ), characterizing the contraction/expansion of yield surface with increasing temperatures, decreases from positive to negative with the increasing COD. Both the fracture energy and the accumulated dissipated energy present remarkable nonlinearities with several inflection points , implying the complex temperature-dependent fracture resistance . This proposed model was validated with three-point-bending fracturing tests of thermally-treated Beishan granite, fitting well (coefficient: 88.8%–99.7%) with the experimental cohesive tensile strength , critical COD, and the accumulated dissipated energy. Besides, by analyzing the softening curves of cohesive cracks in thermally-treated granite, the positive-negative change of T was consistent with the contraction-expansion transition of the yield surface. This work provides a modeling approach for temperature-dependent fracturing of rock-like materials. • The thermoplastic softening of FPZ is characterized via a thermoplastic framework. • This work proposes a thermoplastic cohesive fracturing model for rocks. • New model parameters were proposed to characterize temperature-dependent fracturing. • The correlation coefficient between the model and test data reaches 88.8%–99.7%. • This work provides a modeling approach for temperature-dependent fracturing of rock.

Quantification of the Complex Crack Geometry Effect on Fracture Resistance Using Strain-Based Finite Element Damage Analysis

Abstract This paper examines the effect of complex crack geometry on the J-resistance curves obtained by strain-based ductile tearing simulation of complex cracked tension (CC(T)) specimens. The damage model is determined by analyzing the results of a smooth bar tensile test and a compact tension (C(T)) specimen toughness test on an SA508 Gr.1a low-alloy steel at 316 °C. The validity of the damage model and simulation method is checked by comparing the fracture test data for two CC(T) specimen tests. To investigate the effect of the complex crack geometry on the crack growth profiles and J-resistance curves, two geometric parameters (namely, the through-wall crack length and the surface crack depth) are systematically varied. It is found that the J-resistance curves for the CC(T) specimens with various through-wall crack lengths and surface crack depths are consistently lower than the corresponding 1 T C(T) J-resistance curves. The effect of the through-wall crack length upon the J-resistance curve is found to be less significant than that of the surface crack depth. Moreover, the J-resistance curve decreases continuously with increasing surface crack depth.

Loading rate effect on mixed mode I/II brittle fracture behavior of PMMA using inclined cracked SBB specimen

This paper investigates the effect of loading rate on the mixed-mode I/II fracture behavior of PolymethylMethacrylate (PMMA). Experimental studies are performed using a novel fracture test specimen which has recently been developed, called short bend beam (SBB), in different loading rates of 1 mm/min, 20 mm/min, and 200 mm/min. Fracture test data are presented for pure mode I, pure mode II, and mixed-mode I/II conditions, thanks to the geometrical configuration offered by the specimen covering a full spectrum of mode mixities. Two fracture criteria including maximum tangential stress (MTS), and generalized maximum tangential stress (GMTS) are employed to predict the onset of fracture and the fracture initiation angle in different loading rates. The MTS criterion only considers the singular crack tip terms associated with the stress intensity factors (SIFs) in the solution while the GMTS includes the T-stress effect as well as the SIF-related terms. While enhanced predictions provided by the GMTS criterion, as compared to MTS results, reveals the significance of including the T-stress term in the theoretical calculations, the critical distance (rc) is also found as another major parameter playing an important role in the fracture behavior. It is shown that the size of rc decreases by increasing the loading rate. Therefore, for the first time, a variable and loading rate dependent rc value is utilized for employment of the GMTS criterion and it is demonstrated that considering variable critical distance can provide acceptable theoretical predictions for different loading rates.

Mixed mode fracture behavior of short-particle engineered wood

The present article discusses the fracture behavior of medium-density fiberboard (MDF) and particleboard (PB), under mixed mode loading conditions. With wide applications in construction, marine and furniture industry, MDF and PB are two well-known, wood-based composites that are made of wood particles and fibers, adhered together using a standard polymer glue. Our examination of the elastic properties of these wooden samples in transverse and longitudinal directions via the digital image correlation (DIC) technique sheds light on the elastic isotropy of the employed MDF and PB sheets. Moreover, with the introduction of an improved three-point bend configuration for in-plane wood fracture tests, the brittle behavior of engineered wood is evidenced, which validates the utilization of the linear elastic fracture mechanic (LEFM) concepts herein. Therefore, within the framework of LEFM, we apply the maximum tangential strain (MTSN) criterion to predict the fracture initiation angles and fracture toughness for wooden specimens. Finally, in a comprehensive Weibull statistical analysis over the MDF and PB fracture test data, it is shown that, the mode II test results can be well-estimated based on the value of KIf, using the MTSN criterion. This is especially beneficial when the probability of mode II fracture is sought after, given the mode I statistical parameters.

Critical Load Prediction in Notched E/Glass-Epoxy-Laminated Composites Using the Virtual Isotropic Material Concept Combined with the Average Strain Energy Density Criterion.

This paper attempts to validate the application of the Virtual Isotropic Material Concept (VIMC) in combination with the average strain energy density (ASED) criterion to predict the critical load in notched laminated composites. This methodology was applied to E/glass–epoxy-laminated composites containing U-notches. For this purpose, a series of fracture test data recently published in the literature on specimens with different notch tip radii, lay-up configurations, and a number of plies were employed. It was shown that the VIMC–ASED combined approach provided satisfactory predictions of the last-ply failure (LPF) loads (i.e., critical loads).

Influence of different stirring speed on fracture properties of wedge splitting specimens

Because the stirring efficiency and the quality of finished products are impacted by the mixing speed of the concrete mixer, the influence of the mixing speed at the same process condition on the mechanical properties of concrete properties should be studied. The test adopts the wedge splitting process, and it indicates that the compressive strength of the concrete reaches its maximum at the stirring speed of 1.4 m/s, and the peak value exists around 1.4 m/s. Furthermore, there is a continuous reduction of the concrete strength at the speed extending. In accordance with the fracture test data, the ratio of crack load/limit load decreases continuously with the increase of mixing speed. The concrete is not liable to crack at a relatively low mixing speed and is unstable while with a significantly high mixing speed. The stirring model is established and the numerical simulation is carried out. Three pressure fields at different rotating speeds are simulated, which directly reflect the pressure distribution and value at different rotating speeds.

Mechanical Fracture and Fatigue Characteristics of Fine-Grained Composite Based on Sodium Hydroxide-Activated Slag Cured under High Relative Humidity

A typical example of an alternative binder to commonly used Portland cement is alkali-activated binders that have high potential as a part of a toolkit for sustainable construction materials. One group of these materials is alkali-activated slag. There is a lack of information about its long-term properties. In addition, its mechanical properties are characterized most often in terms of compressive strength; however, it is not sensitive enough to sufficiently cover the changes in microstructure such as microcracking, and thus, it poses a potential risk for practical utilization. Consequently, the present study deals with the determination of long-term mechanical fracture and fatigue parameters of the fine-grained composites based on this interesting binder. The mechanical fracture parameters are primarily obtained through the direct evaluation of fracture test data via the effective crack model, the work-of-fracture method, the double-K fracture model, and complemented by parameter identification using the inverse analysis. The outcome of cyclic/fatigue fracture tests is represented by a Wöhler curve. The results presented in this article represent the complex information about material behavior and valuable input parameters for material models used for numerical simulations of crack propagation in this quasi-brittle material.