Failure Modes Research Articles

In situ SEM fatigue testing technology for metallic materials: a review.

Fatigue failure is one of the most common fracture modes of structural materials in the industrial field. The study of material fatigue mechanisms and methods for predicting fatigue life has always been of significant interest to researchers due to the abrupt and catastrophic failure mode. In recent decades, the performance and functionality of scanning electron microscopy (SEM) have been continuously improved and expanded. Based on this, the development of in situ fatigue testing in SEM has been rapidly developed. This technology plays a crucial role in providing insights into the deformation behavior of materials under fatigue. Keeping this in view, a comprehensive review of the development and application methods of in situ SEM fatigue testing technology is provided here. The development of in situ SEM fatigue testing devices is provided in brief overview, and the application and research progress of this technology in some representative metal structural materials (nickel-based single-crystal superalloys, steel, aluminum alloys and additive manufacturing materials) are analyzed in detail. Moreover, the perspectives on evaluating fatigue damage, particularly about small cracks and the plastic accumulations fatigue behavior, are presented in this study, utilizing the latest advancements in in situ SEM fatigue testing. Remarks about the present and outlook for future work to be done are then provided.

Bending performance of parallel bamboo strand lumber under high-temperature treatment

ABSTRACT Parallel bamboo strand lumber (PBSL) is economical and environmentally friendly and has good mechanical properties, but as a combustible material, there is a lack of research on its bending performance at high temperatures. In this paper, specimens of moso-bamboo-based PBSL were prepared and three-point bending tests were conducted at 11 temperatures ranging from 20 to 270°C using a temperature-controlled box. It was observed that the modulus of rupture (MOR) and modulus of elasticity (MOE) were basically inversely proportional to the temperature. Meanwhile, the color changes, bending failure modes and load-displacement curves of PBSL at different temperatures were compiled. In addition, the mass loss of the specimens was calculated and the microstructure of PBSL was analyzed by electron microscopy scanning. The results showed that the high temperature had a significant effect on the moisture content of PBSL and its internal structure, which was manifested as the weakening of the MOR at the macroscopic level. Finally, the fitting equations for the temperature-dependent changes in MOR and MOE reduction factor of PBSL are proposed in this paper, which provide a reference for predicting the performance of PBSL components under high-temperature conditions.

A novel failure mode and effect analysis model based on extended interval-valued q-rung orthopair fuzzy approach for risk analysis

The failure mode and effect analysis (FMEA) is an essential technique for risk assessment that can not only determine the potential failure modes, causes of failure and effects, but also expunge the potential failure modes in a system. Imprecise evaluation outcomes may be achieved due to the inherent imperfections caused by the traditional FMEA approach. Accordingly, a hybrid FMEA model based upon the interval-valued q-rung orthopair fuzzy (IVq-ROF) set and extended weighted aggregated sum product assessment (WASPAS) method is propounded to provide decision support for risk assessment. The main dedications of this investigation are as below. First, an innovative IVq-ROF score function is presented to compare the IVq-ROF numbers and the related properties of the proposed function are also discussed. Second, the IVq-ROF Aczel–Alsina operation laws are investigated and then some novel IVq-ROF Hamy mean operators are propounded on based on the advanced operations. Third, the IVq-ROF logarithmic percentage change-driven objective weighting (LOPCOW) method is advanced based on the presented score function to determine the objective importance of the risk criteria and the fuzzy full consistency method (FUCOM) is utilized to ascertain the subjective importance of the risk criteria. Fourth, a novel FMEA model based on extended WASPAS method is presented to ascertain the prioritization of failure modes. Lastly, an empirical about risk assessment in the shipbuilding process is implemented to verify the applicability and feasibility of the designed FMEA model. The comparison analysis and sensibility study are executed to demonstrate the significant merits and stability of the developed model. The best advantage of the presented model is that it not only obtains a consistent outcome and takes into account the interrelations among the risk criteria, but also addresses more problems where the weights of the criteria and experts are not determined in advance.

Strength analysis method of CMCs tip shroud structure considering random distribution of preform properties

This paper considers the impact of the random distribution of yarn properties on the mechanical and failure behavior of ceramic matrix composites (CMCs) structures and proposes an integrated analysis method based on preform-structure. Tensile tests of CMCs tip shroud specimens were carried out, and the digital image correlation technique was used to record the deformation of the specimens in real-time during loading. Based on the actual structure, a preform model of the CMCs tip shroud was established, and the kernel density estimation method was used to obtain the distribution of the yarn cross-sectional area. The random distribution of the cross-sectional area is equivalent to material properties, simulating the dispersion of the performance of CMCs. The progressive damage method simulates the failure mode during the specimen's loading process. The peak load error is 1.5 %, and the failure modes such as transverse shear damage, stitching yarn fracture, and interlaminar separation were successfully predicted.

Fracture Resistance and Push-Out Bond Strength of Three Post Types in the Restoration of Anterior Primary Teeth - A In Vitro study.

Restoration fractures and displacement are the two main causes of failure after the rehabilitation of severely worn primary anterior teeth. Compare the effect of three post types on the fracture and push-out bond strength. Sixty undamaged maxillary anterior primary teeth were allocated into three groups according to post type: (I) Tetric N Ceram composite post, (II) prefabricated glass fiber post, and (III) high viscous glass ionomer post. Each group was further subdivided into two sub-groups depending on the test used: fracture resistance test and push-out bond strength test. The all specimens were mounted in acrylic resin blocks and tested using a universal testing machine. The fracture and failure mode were determined by a stereomicroscope inspection of all the specimens. Data were analyzed by one-way analysis of variance (ANOVA) and the Bonferroni post hoc test (P < 0.05). There was a statistically significant difference between fracture resistance and push-out bond strength values for the experimental groups (P < 0.05). The most significant fracture resistance value was in Group II and core/post fracture (restorable fracture) was the most obvious fracture in the three groups with the highest percentage in Group I. The most significant push-out bond strength value was in Group I and adhesive failure between dentin and luting cement/post was the most common type in the groups. The fracture resistance and push-out bond strength were affected by the type of post (P = 0.000). Prefabricated glass fiber posts showed the highest fracture resistance in this study. However, Tetric N Ceram composite posts had the most restorable fracture. Tetric N Ceram composite posts had the highest bond strength with adhesive failure mode.

Insights into molecular and bulk mechanical properties of glassy carbon through molecular dynamics simulations and mechanical tensile testing

With increasing interest in the use of glassy carbon (GC) for a broad range of application areas, the need for developing a fundamental understanding of its mechanical properties has come to the forefront. Furthermore, recent theoretical and modeling works that highlight the synthesis of GC via the pyrolysis of polymer precursors has explored the possibilities of a revisit to the investigation of their mechanical properties at a fundamental level. Although there are isolated reports on the experimental determination of its elastic modulus, insights into the stress-strain behavior of a GC material under tension and compression obtained through simulations, either at the molecular level or for the bulk materials, are missing. This study fills the gap at the molecular level and investigates the mechanical properties of GC using molecular dynamics (MD) simulations, which model the atomistic-level formation and breaking of bonds using bond-order-based reactive force field formulations. The molecular model considered in this simulation has a characteristic 3D cage-like structure of five-, six-, and seven-membered carbon rings and graphitic domains of a flat graphene-like structure. The GC molecular model was subjected to loading under varying strain rates (0.4, 0.6, 1.25, and 2.5 ns−1) and temperatures (300 K–800 K) in each of the three axes: x, y, and z. The simulations show that the GC nanostructure has distinct stress-strain curves under tension and compression. In tension, MD modeling predicted a mean elastic modulus of 5.71GPa for a single GC nanostructure with some dependency on the strain rate and temperature, whereas, in compression, the elastic modulus was also found to depend on the strain rate and temperature and was predicted to have a mean value of 35 GPa. To validate the simulation results and develop experimental insights into the bulk behavior, mechanical tests were conducted on dog-bone-shaped testing coupons that were subjected to uniaxial tension and loaded until failure. The GC test coupons demonstrated a bulk modulus of 17 ±2.69 GPa in tension, which compares well with those reported in the literature. However, comparing MD simulation outcomes to those of uniaxial mechanical testing reveals that the bulk modulus of GC in tension found experimentally is higher than the modulus of single GC nanostructures predicted by MD modeling, which inherently underestimates the bulk modulus. With regard to failure modes, the MD simulations predicted failure in tension accompanied by the breaking of carbon rings within the molecular structure. In contrast, the mechanical testing demonstrated that failure modes are dominated by brittle failure planes largely due to the amorphous structure of GC.

Pull-out test of hybrid connection in steel-UHPC composite slab

This paper presents an experimental study on tensile behavior of steel and ultra-high performance concrete (UHPC) composite structure connected by different connections including epoxy resin adhesive, headed stud, and hybrid of the former two. Thirty-two pull-out tests are conducted by taking the connection type, specimen size and steel fiber content of UHPC as the main parameters. The influences of these main parameters on the failure mode, load-separation behavior, and ultimate resistance of connection are researched. The failure modes of specimens with hybrid connection are UHPC interface debonding and UHPC cone failure, which is identical with the epoxy resin adhesive connection and headed stud connection, respectively. The tensile resistance ratio of headed stud connection to epoxy resin adhesive connection has a significant influence both on the separation performance and tensile resistance of hybrid connection. An empirical equation for predicting the tensile resistance of hybrid connection was proposed by taking the tensile resistance ratio of headed stud to epoxy resin adhesive. The ratio of predicted to test result was 0.973with standard deviations of 0.070. The pull-out tests and analysis of the hybrid connection in steel-UHPC composite structure were still needed to study to get it improved.

Study on the mechanical properties of recycled brick coarse aggregate concrete based on finite element modeling

In recent years, the use of recycled materials in concrete production has garnered significant attention due to their environmental and economic benefits. To promote the application of recycled aggregates, this study focuses on investigating the utilization of Recycled Brick Coarse Aggregate (RBCA) as a substitute for natural aggregate. This paper presents the development of stochastic convex polygonal RBCA through the utilization of a custom-programmed algorithm and proposes a finite element model designed to simulate the behavior of RBCA concrete under compression and splitting tensile. Numerical simulations were conducted to investigate the effects of brick aggregate Replacement Rate (RR) and porosity on the compressive and splitting tensile properties of RBCA concrete. A strong correlation was found between the Concrete Damage Plasticity (CDP) model developed in this study and experimental results, indicating high reliability. The results indicate that the replacement rate of brick aggregates has a more significant impact on the compressive strength than on the splitting tensile strength of concrete. Furthermore, the distribution of coarse aggregates and pores has a minor influence on the mechanical properties and ultimate failure mode of RBCA concrete but significantly affects the crack distribution pattern. The sequence of damage initiation in RBCA concrete was found to be: pores, old Interfacial Transition Zone (ITZ), old mortar, new ITZ, new mortar, RBCA, and Natural Coarse Aggregate (NCA). These findings contribute to a comprehensive understanding of RBCA's performance and offer valuable insights for optimizing its behavior.

Finite element data-driven deep learning-based tensile failure analysis of precast bridge slab joint

The joint is a critical component that facilitates force transmission across precast bridge slabs while maintaining structural integrity. Finite Element Analysis (FEA) is commonly used to examine the mechanical properties and load-bearing capacity of joints with different configurations. However, the repetitive process of “modeling-meshing-computing” consumes substantial manpower, time, and expertise. This study proposes an approach consisting of three key steps: (1) predicting strain distributions, (2) determining failure modes, and (3) analyzing interpretability of predicted results. Specifically, DeepLabv3+ is used to map the Finite Element (FE) model to strain distributions. A binary classification model based on VGG-16 predicts the failure state of the specimen. Interpretability analysis, using Gradient-weighted Class Activation Mapping (Grad-CAM), provides insights into the neural network’s decision-making process. The optimized models achieve a Mean Intersection over Union (MIoU) of 0.5691 for strain distribution prediction on the cross-sectional surface and 0.6424 on the front surface. The failure detection model achieves an F1 score of 0.992 in determining failure states. The interpretability results align well with fracture mechanics theory, enhancing confidence in the model’s predictions. This method serves as a surrogate to reduce the workload of finite element analyses, facilitating strain analysis and failure detection.

Compressive stress-strain relationship of steam free reactive powder concrete at ultra-low temperatures

To explore the applicability of reactive powder concrete (RPC) as a material for LNG storage tanks, the mechanical properties of RPC at ultra-low temperatures were investigate in this paper. Forty-two axial compressive strength tests were conducted on RPC prisms at 20 °C ∼ −165 °C. The influence of temperature and steel fiber on the compressive stress-strain relationship of RPC at ultra-low temperatures was evaluated. The results showed that the axial compressive strength of RPC increases at low temperatures, with a compressive strength increase of over 70 % at −165 °C compared to room temperature. The increase in compressive strength of RPC at ultra-low temperatures is significantly greater than that of ordinary concrete. A relation for predicting the axial compressive strength development of RPC at ultra-low temperatures was also proposed. Steel fibers can increase the toughness of RPC at ultra-low temperatures to a certain extent, and effectively improve the failure mode of RPC, allowing the damaged RPC to maintain its integrity. This work provides a basis for RPC applicability as LNG storage tanks.

Experimental study on the mechanical characteristics of weakly cemented mudstone under different loading rates

With the gradual shift of coal mining to the western coal mining region of China, floor heave in weakly cemented mudstone roadways has become an issue affecting the safety and efficiency of coal mine production. Additionally, different mining rates can lead to fluctuating support stresses on the roof and floor of weakly cemented mudstone roadways. Therefore, obtaining a comprehensive understanding of the mechanical properties of weakly cemented mudstone at different loading rates is conducive to improving the issue of floor heave in such roadways and provides a theoretical basis for further study. In this context, a series of uniaxial mechanical tests with concurrent acoustic emission monitoring were conducted on specimens of weakly cemented mudstone under various loading rates (0.005, 0.01, 0.05, and 0.1 mm/s). The stress‒strain and acoustic emission response curves were obtained to effectively characterize the strength, deformation, damage, macroscale instability, and crack propagation characteristics of the mudstone under the influence of loading rate effects. The research results support the following findings: (1) With increasing loading rate, the peak strength and elastic modulus of weakly cemented mudstone significantly increase, while the peak axial strain and peak radial deformation significantly decrease. (2) With increasing loading rate, the stress required to trigger the expansion of weakly cemented mudstone gradually increases, and a significant power-law relationship arises between the strain of the mudstone at the start of expansion and the loading rate. (3) With increasing loading rate, the acoustic emission ringing count of weakly cemented mudstone increases: The failure of weakly cemented mudstone changes from small-range progressive failure to sudden failure, and the failure mode transitions from shear failure to tensile‒shear composite failure. (4) The studied mudstone damage variables increase with increasing loading rate, following an approximate exponential function. The conclusions obtained in this work can provide a theoretical basis for the evolution mechanism and control of floor heave in deep roadway mining.

Compressive stress-strain relationship of steam free reactive powder concrete at ultra-low temperatures

To explore the applicability of reactive powder concrete (RPC) as a material for LNG storage tanks, the mechanical properties of RPC at ultra-low temperatures were investigate in this paper. Forty-two axial compressive strength tests were conducted on RPC prisms at 20 °C ∼ −165 °C. The influence of temperature and steel fiber on the compressive stress-strain relationship of RPC at ultra-low temperatures was evaluated. The results showed that the axial compressive strength of RPC increases at low temperatures, with a compressive strength increase of over 70 % at −165 °C compared to room temperature. The increase in compressive strength of RPC at ultra-low temperatures is significantly greater than that of ordinary concrete. A relation for predicting the axial compressive strength development of RPC at ultra-low temperatures was also proposed. Steel fibers can increase the toughness of RPC at ultra-low temperatures to a certain extent, and effectively improve the failure mode of RPC, allowing the damaged RPC to maintain its integrity. This work provides a basis for RPC applicability as LNG storage tanks.

Nanocarbon architecture-dependent strengthening and deformation in Al matrix composites

The extraordinary strength of inner graphene walls in carbon nanotube (CNT) is barely exerted due to the weak inner-wall shear resistance, which extremely limits its load-bearing capability. To overcome such deficiency, nanocarbon architecture engineering from CNT to graphene nanoribbon (GNR) was performed via longitudinal unzipping of multi-walled CNT, which was utilized to reinforce pure Al. Results show that the activation volume of composites at macroyielding point, evaluated by stress relaxation experiments, monotonically decreases from CNT/Al to GNR/Al, which results in the continuous increase of critical resolved shear stress (CRSS) called for dislocation nucleation/cross-slip at the grain boundaries. Shear-lag model and numerical simulations demonstrate the increased load-transfer effect from CNT/Al to GNR/Al. Meanwhile, the isotropic and kinematic hardening in nanocarbon/Al composites were investigated both by loading-unloading-reloading tests and strain hardening model on basis of dislocation behavior, wherein the effective stress was determined as being larger than back stress in the composites. Detailed analysis further indicates that the nanocarbon architecture from CNT to GNR increases the back stress strengthening due to the enhanced dislocation accumulation at nanocarbon/Al interface. Moreover, as CNT was unfolded to GNR, the failure mode of reinforcements in the composites gradually changed from pull-out to breakage.

Behavior of reinforced CHS T-joints by welding collar plates under load

The paper presents a comprehensive test program on collar plate reinforced CHS T-joints under different preload conditions, in order to investigate the effect of preload and welding thermal on reinforced joints. A total of four specimens, including specimens with and without preload when the collar plates were welded, were tested under brace axial loading. The test results, including welding temperature field, development of strain as well as welding residual deformation during the welding process are measured and presented in this paper. Furthermore, the failure model and compressive strength of the collar plate reinforced T-joints were determined. The test results demonstrated that the localized high temperature and rapid attenuation are the characteristics of the welding temperature field, which instantaneous peak temperature rose to 1808 °C at the local area and attenuated to 600 °C in an elliptic range of about 3.1 cm × 1.7 cm. The failure modes of collar plate reinforced CHS T-joints do not change with preload on the chord and welding thermal. Furthermore, preload on the chord reduces the compressive strength of reinforced joints. The strain distribution and residual deformation are affected by the thermal expansion and cold shrinkage, while the development of the welding temperature field is not affected by the preload. Finally, for compressive strength of CHS T-joints reinforced with collar plate by welding, the applicability of the reduction coefficient due to preload calculated by existing codes was assessed by comparing design values with experimental results. A finite element model by ANSYS, considering the welding heat, was established. Key parameters affecting the strength of the T-joint at the reinforced collar plate under load were identified through parametric study with finite element models. Construction recommendations of welded CHS T-joints are proposed.

Crash analysis of glass mat thermoplastic (GF/PA6) tubes considering splaying failure mode and energy absorption

Glass mat thermoplastic tubes are potential materials for improving crashworthiness owing to their excellent crash energy absorption capability due to their splaying failure mode of glass mat thermoplastic tubes, which must be considered in the crash analysis to accurately predict their crash performance. This study investigates the crash analysis of glass-mat thermoplastic composite tubes to realize the splaying failure mode and crash energy absorption capability. We evaluated the mechanical properties and fracture toughness of advanced glass mat thermoplastics, termed multi-layered hybrid mats, and employed the result in a 3D Hashin-type continuum damage model implemented with a user material subroutine. For the crash analysis of glass mat thermoplastic tubes, a three-dimensional finite element (FE) model, including cohesive elements in the middle layer of the tube to simulate the splaying failure mode, was constructed. In addition, in the process of the efficient FE modeling of the crash tube, the fracture toughness correction factor was proposed and optimized to calibrate the energy absorption in conjunction with crash test results, as interlaminar fracture modeling causes a difference in energy absorption between the actual test and simulation. As a result, the proposed crash analysis predicted the energy absorption capacity and a splaying failure mode of glass-mat thermoplastic tubes, demonstrating strong concordance with experimental results.

Dynamic responses of rubberised concrete: A study using short-length F-shape barriers subjected to pendulum impact

This study evaluates rubberised concrete barriers' dynamic responses and failure mechanisms subjected to pendulum impacts. We constructed short-length F-shaped barriers from concrete mixed with varying proportions of steel fibres (0 %, 1 % and 2 %) and recycled crumb rubber (0 %, 30 % and 60 %). These barriers were then tested under controlled pendulum impacts, where we measured their peak impact forces, displacements, and energy absorption capacities at different impact velocities. Our findings reveal that barriers with rubber displayed significantly higher energy absorption and lower peak impact forces at low velocities than standard concrete barriers. Conversely, incorporating steel fibres into rubberised concrete increased the peak impact forces and reduced displacements, indicating enhanced stiffness. The experimental data facilitated the development of a predictive equation for peak impact forces, accounting for impact velocity and material composition. This research demonstrates rubberised concrete's less hazardous failure modes and enhanced impact resistance and energy absorption capabilities when used in roadside barriers. Our findings offer valuable insights for developing safer, more resilient infrastructure and contributing to environmental sustainability by repurposing waste materials.

Study of the flexural behavior of UHPC-HPC composite beams strengthened with BFRP sheet after chloride secondary erosion

To solve the issue of insufficient durability of reinforced concrete (RC) structures, a new structure of ultra-high performance concrete (UHPC)-high performance concrete (HPC) composite beam was designed, and the flexural performance of the composite beam strengthened with basalt fiber reinforced polymer (BFRP) after pre-damage was investigated. Results indicate that main cracks are formed and developed after the secondary erosion of chloride salt, leading to three forms of failure modes of the beams: BFRP sheet fracture and concrete crushing, BFRP sheet debonding and concrete crushing and BFRP sheet debonding. The test beam failure process can be classified into three stages: linear elasticity, crack development and yield. The maximum cracking and ultimate loads increased by 27.9 % and 35.8 %, respectively. The crack load growth rate of the beam decreased after 7 days (d) of secondary chloride salt erosion. The formula for calculating the peel strength of the UHPC-HPC composite beam was modified. The calculated bending capacity of the beam agrees well with the measured value. This study provides a reference for enhancing the lifespan and calculating the flexural bearing capacity of structures in corrosive environments.

Fatigue performance simulation of reinforced concrete beams externally strengthened with side bonded CFRP sheets

Damaged Reinforced Concrete (RC) beams are commonly strengthened by bonding Carbon Fiber Reinforced Polymer (CFRP) strips to their soffits. However, inaccessible or narrow soffits limit the use of bottom-bonded CFRP strips. The Side Bonded (SB) CFRP technique overcomes this, yet studies on SB-CFRP-reinforced beams' fatigue behavior are limited. This paper presents a Finite Element (FE) model for simulating the fatigue behavior of RC beams externally strengthened with SB-CFRP sheets. The model incorporates cyclic-dependent CFRP-concrete interface degradation. Existing experimental results are utilized to validate its accuracy. Computational analyses are undertaken to explore the effects of CFRP dimensions, load and prestress levels, and end-U-shaped wrapping on fatigue performance. A simple model is proposed to predict fatigue life considering load and prestress levels. The FE model effectively predicts fatigue performance. Parametric studies indicate that narrow CFRP strips are unable to prevent concrete failure under high loads. Fatigue failure modes include rebar ruptures and CFRP delamination. Besides, the end-U-shaped wrapping reduces interface damage, extending fatigue life. The study emphasizes the sensitivity of vibration excitation method to CFRP debonding. The proposed equation efficiently predicts the fatigue life of RC beams with externally bonded CFRP strips on their sides.

Assessment of formalin preserved and fresh frozen quadriceps tendon graft-suture constructs for load to failure testing: a biomechanical cadaveric study.

Fresh-frozen specimen availability and cost may be a barrier for initiation of biomechanical studies where soft tissue is used in a construct with other medical devices. The impact of soft tissue preservation method on the outcomes of biomechanical studies in the specific case of graft-suture constructs is relatively unexplored. This study aimed to observe peak loads and failure modes in biomechanical testing of fresh-frozen (FF) versus formalin embalmed (FE) quadriceps tendon (QT) graft-suture constructs for soft tissue fixation in ACLR and assess suitability of FE QT graft constructs for load-to-fail testing. Twenty QT grafts were harvested from human cadaver specimens. Ten grafts came from fresh-frozen donors and 10 from embalmed donors. All grafts were prepared with the modified Prusik knot using a braided composite suture and subjected to tensile loading. Comparisons between the biomechanical properties of the graft-suture constructs were made with unpaired t tests with α = 0.05. FE and FF constructs displayed similar peak loads and failure modes. FF constructs had greater elongation after pre-tensioning than FE (7.3 vs. 5.5mm, p = 0.02) and greater elongation after cyclic loading than FE constructs (17.5 vs. 10.5mm, p = 0.01). Hysteresis was greater for FF constructs at the 50th, 100th, 150th, and 200th cycle (p = 0.02, p = 0.07, p < 0.001, p = 0.004, respectively). FE constructs were stiffer than fresh-frozen (103 vs. 84N/mm, p < 0.001). FE constructs were significantly stiffer but displayed similar peak load and failure mode to FF which was reflective of the strength of the suture material. FE grafts can offer an alternative to FF grafts in graft-suture constructs for biomechanical studies where load at failure and knot security and strength is of main interest.

Cost of Quality Management: Encouraging Business Leaders to Manage and Invest in Quality Enhancement

The quality management is a complex set of constant activities aimed at improving the quality of products and services, regularly evaluating and monitoring it, preventing defects, limiting and reducing malfunctions, and correcting production defects before and after the sale of goods. Ineffective quality management leads to such problems as product returns, claims, replacement or repair, loss of customer base, damage to brand reputation, etc. This paper aims to analyze advanced strategies, methodologies, methods and tools for effective control of quality management costs, ways and means of their strategic integration into the practice of business quality management, emphasize the importance of optimizing the cost of quality management in enterprises. The proposals developed in this article are demonstrated on the example of the woodwork division of MEKKERA (MDM), a subsidiary of the HASNAOUI Group in Algeria. An approach represented in the article combines qualitative and quantitative methods. Qualitative data collection involved semi-structured interviews with four company managers, processed using NVIVO software. The purpose of these interviews was to understand the reasons that led the company to include the evaluation of the Cost of Quality in its quality objectives for 2023, as well as the perspectives and goals aimed for by the company in this initiative. A Quantitative analysis relied on secondary data from the company’s database: direct quality costs were calculated using the P-A-F and Ferrebœuf models, prevention and detection measures’ effectiveness and production process performance were evaluated; key performance indicators for indirect quality acquisition costs were defined. Findings revealed the company exceeded set thresholds for internal and external failure costs, necessitating improvements. Ishikawa method identified causes, and corrective actions were proposed using Failure Mode and Effects Analysis (FMEA).