Lower Stress Concentration Research Articles

Micromechanics based FEM study on the mechanical properties and damage of epoxy reinforced with graphene based nanoplatelets

A numerical micromechanics study is performed to investigate the effect of using graphene nanoplatelets (Gnp) with theoretical maximum properties and reduced graphene oxide (rGOnp) on the mechanical properties and damage mechanism of graphene based nanocomposites. Here we consider brittle matrix cracking and interface debonding as the main damage mechanisms. The results showed that the competition between both mechanisms is affected by nanoplatelets/matrix modulus-mismatch, volume fraction, interface strength and orientation. Gnp showed improved modulus, however, with inferior strength and fracture strain compared to rGOnp. This is due to the large modulus-mismatch of Gnp, which resulted in increasing the stress concentration, matrix cracking and coalescing at lower loads. On the other side, the lower stress concentration of rGOnp allowed for higher load accumulation and increased interface debonding. Applying stronger interface properties was found to suppress the interface debonding, improving strength and fracture strain. Further, aligned nanoplatelets lead to a simultaneous improvement in modulus, strength and fracture strain. This is due to the improved load transfer and activation of toughening mechanisms observed for bioinspired nacre like structures.

Effect of gas mixture on tribological performance of plasma nitrided grey cast iron under dry and lubricated conditions

Grey cast iron is commonly utilized as an engineering material owing to its some properties such as its good machinability, ability to dampen vibrations, low-stress concentration, high thermal conductivity, good castability and low cost. Especially when this material is used as camshaft material, it can be exposed to wear because of its low wear properties. So, various surface treatment is applied to improve tribological properties of the grey cast iron. In this study, the grey cast irons were plasma nitrided under different gas mixture ratios for this aim. The structural, morphological and mechanical properties of plasma nitrided grey cast iron specimens were investigated by XRD, SEM, EDS and microhardness test. Also, tribological properties of unnitrided and nitrided specimens were characterized by tribotester under dry and lubricated conditions.

Field repair of a severely damaged FG/epoxy fuselage

The paper presents development of a repair procedure for a severely damaged primary laminate structure of a light aircraft, certified in accordance with CS22. The procedure was developed with the assumption that it would be a field repair carried out by people of average manual skills, who have not been trained in repairs of composite structures. To develop the procedure, a typical FG/epoxy laminate glider fuselage was used. The primary objective of the repair was to restore the original fuselage stiffness, while maintaining possibly low stress concentrations resulting from the repairs. To facilitate development of the repair, an FE model was developed. It was parametrized to be useful for design of similar repairs of similar structures. The experimental work done with the use of a real structure allowed the authors to verify numerical simulations, which were found to be correct.

Effects of the geometric shape and placing length of a fiber post on the stress distribution in a mandibular premolar tooth: A finite element analysis study

Aim: The aim of this study was to evaluate the effects of two geometrically different fiber post systems and two different placing lengths on the stress distribution of endodontically treated teeth.
 Methodology: Four different mandibular premolar tooth models were created. These models were restored using oval or circular fiber posts with two different placing lengths. An oblique force of 300 N was applied to the top of the tooth, and von Mises stress evaluations were carried out on the dentin tissue, luting cement, and fiber posts.
 Results: The maximum von Mises stresses were observed in the 10-mm long circular fiber post model, while the minimum stresses were seen in the 5-mm long oval fiber post model. In general, the oval fiber post models presented more homogeneous stresses than the circular fiber post models. Moreover, the 10-mm long fiber post models generated greater von Mises stresses than the 5-mm long fiber post models in the dentin tissue and luting cement.
 Conclusion: According to the study findings, the use of oval fiber posts at both placing lengths is suggested for oval shaped root canals due to the lower stress concentrations.

Theoretical study on the efficiency of utilization of nanoclay-CFRP composite materials in the root area of wind turbine blades

In this study, theoretical calculations were performed to determine the most efficient utilization of nanoclays added as reinforcement for CFRP composite materials used for wind turbine blade manufacture. Four different V39 blade models were created, and numerical simulations by FEA were performed. Glass Fibre Reinforced Polymers (GFRP), whole model made of Carbon Fibre Reinforced Polymers/nanoclay (2%) (CFRPN2), Hybrid Glass and Carbon/nanoclay (2%) (HGCN2) and Hybrid Glass and Carbon/nanoclay (5%) (HGCN5). The targeted part was the joining zone between the root and the blade. The most important finding to emerge from this study is that the modest addition of nanoclay (2%) with carbon fiber reinforced polymer leads to a significant stiffer blade, with a minimal deflection, about 70% lower than GFRP. Furthermore, the HGCN2 model is considered to be safer as it has a lower stress concentration than others (52.84 kN/m2). It can be considered that the probability of failure of the entire root area will be decreased if nanoclay-CFRP hybrid blades are used, yielding higher durability and lower overall costs. These findings contribute to decisions related to materials selection, structural, aerodynamic design and layup schedule choice.

Optimizing the deformation behavior of stent with nonuniform Poisson's ratio distribution for curved artery

Stent implantation at a highly curved artery has always been a challenge, considering the relatively high chance of in-stent restenosis (ISR) caused by severe straightening effect and high strain energy over the vessel wall. In this paper, a novel optimization based design method was proposed to manipulate the deformation behavior of the common ring-and-link stent. By changing the location of the connection point between rings and links, traditional ring-and-link structure was modified to achiever tunable Poisson's ratio (PR). With the nonuniform cellular structure design method proposed in a previous study, PR distribution of the stent structure was optimized to achieve the desired curvature. As a result, the obtained stent structure with nonuniform PR could perfectly fit into the curved artery after expansion, without causing any obvious vessel straightening. To validate the proposed method, two different vessel models were introduced. Firstly, a short vessel with a constant curvature was set as the design objective, and both numerical and experimental tests were conducted. Further, a patient-specific vessel was applied. Both test results showed that optimized stents would cause much smaller vessel straightening. Moreover, vessels stented by the optimized structures had much lower stress concentration and strain energy. All those properties will decrease the possibility of ISR significantly.

Stress concentration factors of bird-beak SHS X-joints under brace axial forces

ABSTRACT Bird-beak joints are a new type of welded square hollow section (SHS) joints and their fatigue behaviors are of the most attentions recently. The stress concentration factors (SCFs) of both square and diamond bird-beak X-joints under brace axial forces were systematically investigated in this research by using experimental and numerical methods. Four specimens including two square bird-beak X-joints and two diamond bird-beak X-joints were tested. Elastic strain distributions within crown and saddle areas were measured, and the strain concentration factors (SNCFs) at specified hot spots were obtained by using the quadratic extrapolation approach. Refined finite element models, whose accuracies have been validated by experimental data, were developed to parametrically simulate the stress concentrations at weld toes of such innovative joints. The influences of three non-dimension parameters (i.e., brace/chord width ratio β , chord wall slenderness ratio 2 γ , and brace/chord wall thickness ratio τ ) on SCFs of bird-beak X-joints were revealed. Comparison also shows that the saddle areas commonly contain the highest SCFs within whole joint, and that square bird-beak X-joints provide lower stress concentrations than diamond ones in case of identical non-dimensional parameters. Based on numerous results from parametric analysis, design formulas were finally proposed to calculate the SCFs at typical hot spots of both square and diamond bird-beak X-joints subjected brace axial forces.

Fatigue behavior of ultrafine tabletop ceramic restorations

ObjectiveThe goal of this study was to investigate the fatigue life, failure modes, and stress distribution of partial ultrafine restorations for posterior teeth in different ceramics. MethodsSixty standard tabletop preparations in epoxy resin G10 received lithium-silicate-based zirconia-reinforced (ZLS) or hybrid ceramic (PIC) restorations in 0.5- or 1-mm thickness bonded with resin cement. The same cycling protocol was applied for all specimens, which consisted of 5000 cycles at 200N, followed by 450-N cycles until the specimens’ fracture or the suspension of the test after 1.5×106 cycles. Axial load was carried out with a 4Hz frequency in Biocycle V2 equipment (Biopdi, São Carlos, SP), with samples immersed in water. The presence of cracks and/or fractures was checked every 2.5×105 cycles, and the survival analysis was performed with the number of cycles in which each specimen failed. All specimens were evaluated by stereomicroscopy and scanning electron microscopy (SEM). After data tabulation, Kaplan–Meier and Mantel–Cox (log-rank test) analyses were performed, followed by multiple pairwise comparison, all with a significance level of 5%, and Weibull analysis. Through three-dimensional finite element analysis, stress distribution and maximum principal stresses in the posterior occlusal veneers were evaluated by comparison of different types of substrate (G10, enamel/dentin, enamel), thicknesses, and ceramic materials. ResultsZirconium-reinforced lithium silicate restorations with 0.5-mm thickness (ZLS.5) showed lower fatigue strength compared with that of 1.0-mm hybrid ceramic restorations (PIC1), and both were similar to other restorations (PIC.5 and ZLS1) (log-rank test, χ2=11.2; df=3; p=0.0107<0.05). ZLS groups presented random defects that culminated in fracture, whereas PIC groups presented defects that increased with mechanical fatigue after some cycling time. Stereomicroscope images show radial cracks due to the translucency of the material. There was no damage caused by the applicator. MPS (maximum principal stress) distributions were similar for the different substrate types, but the highest modulus of elasticity showed slightly lower stress concentration. SignificancePIC is more likely to be used in thinner thickness than indicated by the manufacturer, with fatigue strength similar to that of thicker ZLS restorations.

Shear Fracture and Industrial Overload Failure of Mechanical Fuse Shear Pin

The science and engineering application of fracture is attractive and complex in nature. The notch provided shear pin geometry design for lower and known stress concentration factor engineered for premature shear pin fracture failure. The shear pin is one among type of mechanical fuse, safeguard bigger industrial rotary components by premature failure. The notch provided in shear pin act as reduced notch toughness where crack initiation and propagation starts from notch surface due to overload stress in the system. Advancement in technologically of mechanical fuses is one such key area, with which design of engineered microstructure analysis of shear failure discussed extensively. In the present investigation, shear pin failure were characterized to determine root cause analysis. Visual examination of fracture surface reveals pure ductile adiabatic shear fracture and metallographic examinations reveals non uniform size of spheroidal cementite carbide particles distributed uniformly slipping in coarse ferrite matrix plane of maximum shear stress causes the reason for shear fracture phenomena during crack propagation.

Ice Shelf Rift Propagation and the Mechanics of Wave‐Induced Fracture

AbstractDistant storms, tsunamis, and earthquakes generate waves on floating ice shelves. Previous studies, however, have disagreed about whether the resulting wave‐induced stresses may cause ice shelf rift propagation. Most ice shelf rifts show long periods of dormancy suggesting that they have low background stress concentrations and may therefore be susceptible to wave‐induced stresses. Here I quantify wave‐induced stresses on the Ross Ice Shelf Nascent Rift and the Amery Ice Shelf Loose Tooth T2 Rift using passive seismology. I then relate these stresses to a fracture mechanical model of rift propagation that accounts for rift cohesive strength due to refrozen melange, ice inertia, and spatial heterogeneity in fracture toughness due to the presence of high toughness suture zones. I infer wave‐induced stresses using the wave impedance tensor, a rank three tensor that relates seismically observable particle velocities to components of the stress tensor. I find that wave‐induced stresses are an order of magnitude larger on the Ross Ice Shelf as compared to the Amery Ice Shelf. In the absence of additional rift strength, my model predicts that the Nascent Rift should have experienced extensive rift propagation. The observation that no such propagation occurred during this time therefore suggests that the Nascent Rift experiences strengthening from either refrozen melange or rift tip processes zone dynamics. This study illustrates one way in which passive seismology may illuminate glacier calving physics.

Biomechanical analysis of different implant-abutments interfaces in different bone types: An in silico analysis

The purpose of this study was to analyze the stress distribution of bone tissue around implants with different implant-abutment interfaces: platform switching (PSW); external hexagon (EH) and Morse taper (MT) with different diameters (regular: Ø 4 mm and wide: Ø 5 mm), bone types (I–IV) and subjected to axial and oblique load conditions using three-dimensional finite element analysis (3D-FEA). Sixteen 3D models of various configurations were simulated using InVesalius, Rhinoceros 3D 4.0, and SolidWorks 2011 software, and processed using Femap 11.2 and NeiNastran 11.0 programs. Axial and oblique forces of 200 N and 100 N, respectively, applied at the occlusal surface of prostheses. Maximum principal stress values were obtained from the peri-implant cortical bone of each model. Statistical analyses were performed using ANOVA and Tukey's test for maximum principal stress values. Oblique loading showed higher tensile stress than axial loading (P < 0.001). Wide-diameter implants showed lower stress concentration rather than regular-diameter implants, regardless of both connection and bone type (P < 0.001). Under axial loading, wide-diameter EH implants with regular platforms showed more favorable stress distribution than PSW implants for axial loading (P < 0.001); however, under oblique loading, PSW implants exhibited lower stress concentrations (P < 0.001). Regular-diameter MT implants showed lower stress than EH implants (P < 0.001). Bone type IV showed higher stress in the cortical region than bone types I and II (P < 0.001), but no significant difference when compared with bone type III (P > 0.05). The conclusion drawn from this in silico is that MT implants should be considered for use in situations that preclude the placement of wide-diameter implants, particularly where bone types III and IV are concerned.

Pannexin1: a multifunction and multiconductance and/or permeability membrane channel.

Of the three pannexins in vertebrate proteomes, pannexin1 (Panx1) is the only one well characterized, and it is generally accepted that Panx1 functions as an ATP release channel for signaling to other cells. However, the ATP permeability of the channel is only observed with certain stimuli, including low oxygen, mechanical stress, and elevated extracellular potassium ion concentration. Otherwise, the Panx1 channel is selective for chloride ions and exhibits no ATP permeability when stimulated simply by depolarization to positive potentials. A third, irreversible activation of Panx1 follows cleavage of carboxyterminal amino acids by caspase 3. The selectivity/permeability properties of the caspase cleaved channel are unclear as it reportedly has features of both channel conformations. Here we describe the biophysical properties of the channel formed by the truncation mutant Panx1Δ378, which is identical to the caspase-cleaved protein. Consistent with previous findings for the caspase-activated channel, the Panx1Δ378 channel was constitutively active. However, like the voltage-gated channel, the Panx1Δ378 channel had high chloride selectivity, lacked cation permeability, and did not mediate ATP release unless stimulated by extracellular potassium ions. Thus, the caspase-cleaved Panx1 channel should be impermeable to ATP, contrary to previous claims.

In vitro mechanical stimulation facilitates stress dissipation and sealing ability at the conventional glass ionomer cement-dentin interface

ObjectiveThe aim of this study was to evaluate the induced changes in the chemical and mechanical performance at the glass-ionomer cement-dentin interface after mechanical load application. MethodsA conventional glass-ionomer cement (GIC) (Ketac Bond), and a resin-modified glass-ionomer cement (RMGIC) (Vitrebond Plus) were used. Bonded interfaces were stored in simulated body fluid, and then tested or submitted to the mechanical loading challenge. Different loading waveforms were applied: No cycling, 24 h cycled in sine or loaded in sustained hold waveforms. The cement-dentin interface was evaluated using a nano-dynamic mechanical analysis, estimating the complex modulus and tan δ. Atomic Force Microscopy (AFM) imaging, Raman analysis and dye assisted confocal microscopy evaluation (CLSM) were also performed. ResultsThe complex modulus was lower and tan delta was higher at interfaces promoted with the GIC if compared to the RMGIC unloaded. The conventional GIC attained evident reduction of nanoleakage. Mechanical loading favored remineralization and promoted higher complex modulus and lower tan delta values at interfaces with RMGIC, where porosity, micropermeability and nanoleakage were more abundant. ConclusionsMechanical stimuli diminished the resistance to deformation and increased the stored energy at the GIC-dentin interface. The conventional GIC induced less porosity and nanoleakage than RMGIC. The RMGIC increased nanoleakage at the porous interface, and dye sorption appeared within the cement. Both cements created amorphous and crystalline apatites at the interface depending on the type of mechanical loading. Clinical significanceRemineralization, lower stress concentration and resistance to deformation after mechanical loading improved the sealing of the GIC-dentin interface. In vitro oral function will favor high levels of accumulated energy and permits micropermeability at the RMGIC-dentin interface which will become remineralized.

Numerical Shape Optimization of Cervical Spine Disc Prosthesis Prodisc-C

Various ball and socket-type designs of cervical artificial discs are in use or under investigation. All these disc designs claim to restore the normal kinematics of the cervical spine. In this study, we are interested in the cervical prosthesis, which concerns the most sensitive part of the human body, given the movements generated by the head. The goal of this work is to minimize the constraints by numerical shape optimization in the prodisc-C cervical spine prosthesis in order to improve performance and bio-functionality as well as patient relief. Prodisc-C cervical spine prosthesis consists of two cobalt chromium alloy plates and a fixed nucleus. Ultra-high molecular weight polyethylene, on each plate there is a keel to stabilize the prosthesis; this prosthesis allows thee degrees of freedom in rotation. To achieve this goal, a static study was carried out to determine the constraint concentrations on the different components of the prosthesis. Based on the biomechanical behaviour of the spine discs, we totally fixed the lower metal plate; a vertical load of 73.6 N to simulate the weight of the head was applied to the superior metallic endplate. After a static study on this prosthesis, using a finite element model, we noticed that the concentration of the Von-Mises stress is concentrated on the peripheral edge core and the concave articulating surface of the superior metallic endplate the numerical. We use the module optimization for 3D SolidWorks for optimize our design, based on the criteria of minimizing stress value. Shape optimization concluded to minimize the equivalent stress value on both joint surface (concave and convex) from 11.3 MPa to 9.1MPa corresponding to a percentage decrease of 19.4% from the original geometry. We conclude that despite the fact that maximum Von Mises stresses are higher in the case of the dynamic load, remains that they are weak. Which is an advantage for the durability of the prosthesis and-also for the bone, because a low stress concentration on the prosthesis will reduce stress concentration generated by the implant on the bone, therefore its risk of fracture reduces.

Three-Dimensional Finite Element Analysis of Varying Diameter and Connection Type in Implants with High Crown-Implant Ratio.

The aim of this study was to evaluate the effect of varying the diameter, connection type and loading on stress distribution in the cortical bone for implants with a high crown-implant ratio. Six 3D models were simulated with the InVesalius, Rhinoceros 3D 4.0 and SolidWorks 2011 software programs. Models were composed of bone from the posterior mandibular region; they included an implant of 8.5 mm length, diameter Ø 3.75 mm or Ø 5.00 mm and connection types such as external hexagon (EH), internal hexagon (IH) and Morse taper (MT). Models were processed using the Femap 11.2 and NeiNastran 11.0 programs and by using an axial force of 200 N and oblique force of 100 N. Results were recorded in terms of the maximum principal stress. Oblique loading showed high stress in the cortical bone compared to that shown by axial loading. The results showed that implants with a wide diameter showed more favorable stress distribution in the cortical bone region than regular diameter, regardless of the connection type. Morse taper implants showed better stress distribution compared to other connection types, especially in the oblique loading. Thus, oblique loading showed higher stress concentration in cortical bone tissue when compared with axial loading. Wide diameter implant was favorable for improved stress distribution in the cortical bone region, while Morse taper implants showed lower stress concentration than other connections.

Biomechanical Effect of Ferrule on Incisors Restored with a Fiberglass Post and Lithium-Disilicate Ceramic Crown after Thermal Cycling and Fatigue Loading.

To evaluate the biomechanics of endodontically treated incisors restored with a fiberglass post and a CAD/CAM lithium-disilicate ceramic crown with/without a ferrule after thermal and mechanical aging. Twenty bovine incisors were divided into two groups (n = 10): 1. Fe, with a ferrule of 2 mm, and 2. NFe, without a ferrule. After endodontic treatment, the teeth were restored using a fiberglass post (Exacto 3, Angelus) and composite core (Tetric Ceram, Ivoclar Vivadent). They then received a CAD/CAM lithium-disilicate ceramic crown (IPS e.max CAD) luted using a self-adhesive composite (RelyX Unicem 2, 3M Oral Care). All specimens were subjected to 20,000 thermocycles and 2,400,000 simulated chewing cycles. Ceramic crown and root dentin strains (µS) were measured using strain gauges (n = 10) during 100-N loading before and after the thermal and mechanical aging, and upon fracture loading. The specimens were subsequently loaded to fracture (N). The stress distribution was analyzed using 3D individualized finite-element models created by micro-CT of experimental samples (n = 3). Strain data were analyzed using two-way ANOVA and Tukey's HSD test. Fracture resistance was analyzed using Student's t-test and fracture mode was analyzed using the chi-squared test (α = 0.05). After aging, NFe exhibited significantly higher root dentin deformation (buccal: 1248.0 ± 282.8; lingual: 516.2 ± 195.0; p < 0.001) than Fe (buccal, 554.0 ± 233.8; lingual: 311.8 ± 159.0; p < 0.001). The deformation measured on ceramic crowns was not influenced by ferrule presence or aging process. Significantly higher fracture resistance (N) was observed for the Fe (1099.6 ± 214.8) than the NFe group (675.3 ± 113.8) (p < 0.001). The NFe group revealed a lower fracture resistance:root strain ratio than did the Fe group. The stress levels on root dentin and fiberglass were lower for the Fe group. The NFe group showed increased root dentin strain after the aging process. The Fe group revealed higher fracture resistance, lower stress concentration on root dentin and fewer catastrophic fractures.

On the reduction of stress concentration factor in an infinite panel using different radial functionally graded materials

This work deals with a parametric study of the stress concentration factor in different functionally graded material panels having a central circular hole subjected to a uniaxial tensile, biaxial tensile and shear load. The extended finite element method along with isoparametric graded finite element material properties modelling scheme is used to evaluate the stress concentration factor. Three candidate material gradation models are tested in this parametric study and various metal ceramic functionally graded materials are also tested for stress concentration. The stress concentration factor evaluated numerically for a wide range of Young's modulus ratio and power law index are presented. It has been concluded that the low stress concentration factor can be achieved by choosing the proper material gradation model and their power law index for a fixed value of Young's modulus ratio.

Al–5.5Mg–1.5Li–0.5Zn–0.07Sc–0.07Zr alloy produced by gravity casting and heat treatment processing

ABSTRACTAl–5.5Mg–1.5Li–0.5Zn–0.07Sc–0.07Zr alloy was produced by gravity casting and heat treatment processing. After gravity casting based on the melting processing scheme designed specifically for the studied alloy, there was no obvious porosity and slag. In as-cast alloy, there were many network-shaped second phase particles enriched along the grain boundaries, most of which integrated into the α-Al matrix after solution heat treated at 500°C for 10 h. The grain growth was inconspicuous, which means low grain boundary stress concentration resulted by planar slip. To meet the requirement for industrial actuality, avoid the excessively detrimental effect of PFZs and utilize the order hardening effect of δ′ (Al3Li) phases sufficiently, 175°C/8 h was preferred as the aging regime. Optimal comprehensive mechanical properties were obtained after solid solution heat treated process (500°C/10 h) and subsequent aging treatment (175°C/8 h) with elongation, yield strength, and ultimate tensile strength reaching 8.7%, 270.5 MPa, and 435.5 MPa, respectively.

EBSD Analysis of Relationship Between Microstructural Features and Toughness of a Medium-Carbon Quenching and Partitioning Bainitic Steel

A multiphase microstructure of bainite, martensite and retained austenite in a 0.3C bainitic steel was obtained by a novel bainite isothermal transformation plus quenching and partitioning (B-QP) process. The correlations between microstructural features and toughness were investigated by electron backscatter diffraction (EBSD), and the results showed that the multiphase microstructure containing approximately 50% bainite exhibits higher strength (1617 MPa), greater elongation (18.6%) and greater impact toughness (103 J) than the full martensite. The EBSD analysis indicated that the multiphase microstructure with a smaller average local misorientation (1.22°) has a lower inner stress concentration possibility and that the first formed bainitic ferrite plates in the multiphase microstructure can refine subsequently generated packets and blocks. The corresponding packet and block average size decrease from 11.9 and 2.3 to 8.4 and 1.6 μm, respectively. A boundary misorientation analysis indicated that the multiphase microstructure has a higher percentage of high-angle boundaries (67.1%) than the full martensite (57.9%) because of the larger numbers and smaller sizes of packets and blocks. The packet boundary obstructs crack propagation more effectively than the block boundary.

Three-dimensional finite element analysis of glass fiber and cast metal posts with different alloys for reconstruction of teeth without ferrule

The aim of this study was to evaluate different materials for restoration of teeth without ferrule by three-dimensional (3D) finite element analysis (FEA). Five models simulating the maxillary central incisor and surrounding bone were simulated according to the type of post: glass fibre post (GFP) or cast metal post (CMP) with different alloys such as gold (Au), silver–palladium (AgPd), copper–aluminum (CuAl) and nickel–chromium (NiCr). Models were designed using Invesalius and Rhinoceros. FEAs were made using FEMAP and NeiNastran, with an applied axial force of 100 N and oblique occlusal load at 45°. Stress distribution among groups was analysed by two-way analysis of variance (ANOVA), followed by post-hoc Tukey’s test. The GFP showed the best stress distribution in the post, followed by CMP with Au, AgPd, CuAl and NiCr alloys, respectively (p < .001). No statistically significant difference in the stress distribution in teeth was found under application of axial load (p > .05). Under oblique load, the GFP generated the highest values of tension among the models, followed by the CMP with NiCr alloy than other models (p < .001). The use of GFP resulted in a lower stress concentration in the post, but increased stress in the tooth without ferrule. The CMP with NiCr alloy exhibited the highest stress distribution among other CMP. To avoid higher stress in teeth, alloys of Au, AgPd and CuAl, respectively, are recommended.