Preload Moments Research Articles

Performance evaluation of artificial neural networks for identification of failure modes in composite plates

Abstract The aim of this work is to identify failure modes of double pinned sandwich composite plates by using artificial neural networks learning algorithms and then analyze their accuracies for identification. Mechanically pinned specimens with two serial pins/bolts for sandwich composite plates were used for recognition of failure modes which were obtained in previous experimental studies. In addition, the empirical data of the preceding work was determined with various geometric parameters for various applied preload moments. In this study, these geometric parameters and fastened/bolted joint forms were used for training by artificial neural networks. Consequently, ten different backpropagation training algorithms of artificial neural network were applied for classification by using one hundred data values containing three geometrical parameters. According to obtained results, it was seen that the Levenberg-Marquardt backpropagation training algorithm was the most successful algorithm with 93 % accuracy rate and it was appropriate for modeling of this problem. Additionally, performances of all backpropagation training algorithms were discussed taking into account accuracy and error ratios.

Elastic-plastic fracture analysis of external thread of drive shaft shell of a positive displacement motor

For a positive displacement motor (PDM), the threaded joint connecting drive shaft shell (DSS) and universal shaft shell that is close to the bit is inclined to fracture. In this paper, elastic-plastic fracture performance of the threaded connection is simulated under both make-up torque and bending moment. Firstly, an FE model, which includes a cracked external thread of the DSS and an engaging internal thread of the universal shaft shell, is established and validated. Secondly, influences of both plastic deformation and the helix angle on fracture properties of the cracked thread are evaluated quantitatively. Meanwhile interactions between two cracks are also discussed. Finally, under the two kinds of loading conditions, i.e. loaded by pre-load only and loaded by both pre-load and bending moment, explicit relationships between characteristic J-integrals and the crack depth are obtained for the DSS.

A numerical investigation of injury mechanisms and tolerance limit of occupant femur in combined compression–bending load

This study aimed at investigating the femur injury mechanisms and femur injury tolerance limit in combined axial force and bending moment. A finite element (FE) model of the lower extremity in sitting posture was developed and validated against femur three-point bending dynamic test and axial impact test of knee-thigh (KT) complex. Following, the femur fractures in combined compression–bending load were analysed via using an analytical model of the curved beam. At last, six virtual simulation tests were conducted by using the developed femur FE model. Moreover, the femur fracture mechanism was analysed in terms of the fracture location and the calculated failure bending moments from both the analytical and FE models. The results revealed that with the increasing of preload bending moment from 0 to 676 Nm, the femur fracture location transferred from the femoral neck region to the femoral shaft region. In the two simulation tests of femur fractures in femoral neck regions, the peak value of femur bending moment were 285 and 296 Nm, respectively. In the other four tests with femur fractures occurred in shaft region, the fracture femur moment varied from 381 to 443 Nm. The results demonstrated that the occupant femur fracture location and femur fracture tolerance limit were affected by both bending moment and axial compression loads. This study can provides an explanation for the phenomenon that the high prevalence of femoral shaft fractures occurs in real-world car frontal impacts when the axial loads lower than that used in the current injury tolerance of femur.

Effect of preload moment on the strength of mechanically fastened joints in woven glass-epoxy prepregs

Abstract This study presents the effects of geometric parameters of mechanically fastened joints on their ultimate bearing strength, net ultimate tensile strength and ultimate shear strength under ...

A data mining approach to the diagnosis of failure modes for two serial fastened sandwich composite plates

The aim of this study is to diagnose and classify the failure modes for two serial fastened sandwich composite plates using data mining techniques. The composite material used in the study was manufactured using glass fiber reinforced layer and aluminum sheets. Obtained results of previous experimental study for sandwich composite plates, which were mechanically fastened with two serial pins or bolts were used for classification of failure modes. Furthermore, experimental data from previous study consists of different geometrical parameters for various applied preload moments as 0 (pinned), 2, 3, 4, and 5 Nm (bolted). In this study, data mining methods were applied by using these geometrical parameters and pinned/bolted joint configurations. Therefore, three geometrical parameters and 100 test data were used for classification by utilizing support vector machine, Naive Bayes, K-Nearest Neighbors, Logistic Regression, and Random Forest methods. According to experiments, Random Forest method achieved better results than others and it was appropriate for diagnosing and classification of the failure modes. Performances of all data mining methods used were discussed in terms of accuracy and error ratios.

Application of a fuzzy expert system for failure load estimation of two serial pinned or bolted sandwich composite plates

AbstractThe present paper reports about the application of fuzzy expert system for estimating failure loads of two serial pinned/bolted sandwich composite plates. Considered composite material for present application was produced by a glass fiber reinforced layer and aluminum sheets to create sandwich structures. Briefly outlines, the experimental data of a previous study were related to different geometrical boundary conditions and also numerous preload moments as 0 (pinned), 2, 3, 4 and 5 (bolted) Nm. Anyway, both a fuzzy expert system and a regression analysis were applied depending on mentioned geometrical parameters and pinned/bolted joint arrangements in this work. Obtained results point out that the fuzzy expert system was more suitable than regression analysis method for modeling and estimation of analyzed sandwich composite. Achievements of the fuzzy expert system and the regression analysis methods were considered in terms of error ratios and mean absolute deviations.

熱負荷を受けるボルト締結体の軸力と曲げモーメントの簡易推定法

熱負荷を受けるボルト締結体の軸力と曲げモーメントの簡易推定法

Failure Prediction of Cross-Ply Laminated Double-Serial Mechanically Fastened Composites using Fuzzy Expert System

The scope of this study is to create a model that predicts failure loads for mechanically fastened composite plates using a fuzzy expert system. The composite material used in the study was manufactured in both a fibre reinforced manner and with glass fibres. The results of a previous experimental study for cross-ply laminated composite plates that were mechanically fastened with two serial pins or bolts were used to model and predict of failure loads. Furthermore, experimental data of a preceding study were obtained with different geometrical parameters for various applied preload moments (pinned/bolted) as 2, 3, 4 and 5 Nm. In this study, a fuzzy expert system and regression analysis methods were applied by using these geometrical parameters and pinned/bolted joint configurations. Therefore, 5 geometrical parameters and 300 test data were used. According to obtained results, it was determined that the fuzzy expert system was more appropriate than the regression analysis method for modelling and prediction. Performances of the fuzzy expert system and regression analysis method were discussed in terms of error ratios and mean absolute deviations.

Fuzzy logic model for the prediction failure analysis of composite plates under various cure temperatures

In this study, stress values were examined in pin/bolt connected composite plates which were applied preload and non-preload moment. Composite plates were produced with different curing cycles and geometric dimensions. Failure analysis of composite plates was carried out by applying different preload moments. The results obtained from experimental study were processed using fuzzy model. The results of experiments and fuzzy model were presented as a comparative. As a result of the comparison, it can be said that the initial stress values of failure were approximately determined using fuzzy model.

Failure Response of Two Serial Bolted Joints in Composite Laminates

ABSTRACTIn this study, the failure response of two serial bolted joints in composite laminates was investigated. The composite material was consisted of epoxy matrix and glass fibers. To find out the effects of joint geometry and stacking sequences on the failure response, parametric studies were performed experimentally. Three different geometrical parameters that were the edge distance-to-hole diameter ratio (E/D), plate width-to-hole diameter ratio (W/D) and the distance between two serial holes-to-hole diameter ratio (K/D) were investigated. Hence, E/D, W/D and K/D ratios were considered from 1 to 5, 2 to 5 and 3 to 5, respectively. In addition, the failure tests were carried out for a range of preload moments as 2, 3, 4, 5 Nm and without any preload moments as 0Nm. Tested composite laminates were oriented two different stacking sequences as [0°]8 and [0°/0°/90°/90°]s. Experimental results point out that failure response of two serial bolted composite joints are firmly effected from material parameters, geometrical parameters and the magnitudes of applied preload moments.

An Experimental Study of Mechanically Fastened Composite Joints with Clearance

In this article, the bearing strengths, failure modes, and joint geometries of woven glass-epoxy prepreg composite mechanically fastened joints with clearance subjected to preload moments were studied experimentally. Two different geometrical parameters were investigated. Therefore; the edge distance-to-pin diameter (E/d) and width-to-pin diameter (W/d) ratios were systematically varied and corresponding failure modes and loads were defined. The preload moments were selected as 0 and 2 Nm. The experiments were also carried out under a clearance for the diameters of the pin and the circular hole for 5 and 5.2 mm, respectively. Damage of specimens with clearance was examined using scanning electron microscope. The experimental results obtained from joints with clearance were compared with the earlier results that were not including clearance. It was observed that the effect of clearance on the bearing strength of mechanically fastened joints is significant. The failure loads of the composite joints with preload moment were larger than those of the composite joints without preload moment. Also, if geometrical parameters of mechanically fastened composite joints are varied, the failure modes and loads are strictly influenced from this variation.

Failure Load of Mechanically Fastened Immersed Composite Laminated Plates under a Preloaded Moment

The effect of water absorption and corrosive sea water on the failure response of an angle ply glass fibre reinforced-epoxy composite oriented as [0/0/90/45]s has been experimentally investigated. The specimens were first tested in unimmersed conditions, and afterwards another group of specimens was immersed in sea water for 200 days. The experiments were performed using some parameters for the pinned and bolted specimens. The specimens were tested under pre-load moments of 3 Nm and 6 Nm. The results point out that the pre-load moments increase the failure load. Moreover, immersion of the composite specimens into the sea water under preload moments can cause a notable decrease of the failure load.

Failure loads of mechanical fastened pinned and bolted composite joints with two serial holes

An experimental and numerical study has been carried out to investigate the first failure load and the bearing strength behavior of pinned joints of glass fiber reinforced woven epoxy composite prepregs with two serial holes subjected to traction forces by two serial rigid pins. In the experiments, a number of parameters such as the edge distance-to- upper hole diameter (E/D), the distance between center of two holes-to-hole diameter (K/D), and the width of the specimen-to-hole diameter (W/D) were varied. Each specimen configuration was analyzed using the finite element model. Generally, comparison between computed and experimental results for first failure load presented a good agreement. Also to see the effects of preload moments and sea water on the bearing strength of joints an experimental investigation was carried out. For this purpose, the specimens were tested under 3 and 6Nm preload moments for unimmersed condition. Other specimens held in sea water for 24h. Afterwards, the same experiments were performed to the immersed specimens. It was observed that the immersion of test specimens into sea water causes a decrease in the failure load without a preload moment. The test specimens under preload moments produce nearly the same bearing strength as unimmersed specimens.

Experimental and numerical failure analysis of carbon/epoxy laminated composite joints under different conditions

The aim of this study is to investigate the effects of preload moment, moisture and interference-fit on bearing strength and failure mode in pin-jointed and bolted carbon–epoxy plates which were subjected to a traction force. Two different geometrical parameters, end distance to pin diameter ratio ( E/ D) and width to pin diameter ratio ( W/ D), were considered experimentally. E/ D and W/ D ratios were selected ranging from 1 to 4 and from 2 to 4, respectively. The test results showed that the ultimate failure loads were directly affected by the geometrical parameters, preload moments and interference-fit. Furthermore, for the specimens in wet condition, failure loads increased with preload moments while failure loads stayed almost the same in non-preloaded specimens. Finite element models of the specimens were also developed by using ANSYS software. Contact and stress analyses of the models were carried out for both free and interference-fit. Tsai-Wu criterion was used to determine bearing strength corresponding to first failure load. It was concluded that the numerical results are in good agreement with experimental results.

The influences of geometrical parameters on the failure response of two serial pinned/bolted composite joints

In this study, the influences of geometrical parameters on the failure response of two serial pinned/bolted composite joints were analysed. The tested composite material consisted of epoxy matrix and glass fibres. It was oriented as [0°/ 0°/ 60°/ 60°]s, symmetrically. Three different geometrical parameters, which were the edge distance-to-hole diameter ratio ( E/ D), plate width-to-hole diameter ratio ( W/ D), and the distance between two serial holes-to-hole diameter ratio ( K/ D), were investigated, experimentally. Consequently, E/ D, W/ D, and K/ D ratios were designed from 1 to 5, 2 to 5, and 3 to 5, respectively. Additionally, the failure tests were performed for a range of preload moments as 2, 3, 4, 5Nm and without any preload moment as 0Nm. Experimental results showed that the changing of geometrical parameters and the presence of preload moments affected failure behaviour of two serial pinned/bolted composite joints. Furthermore, the numerical failure analysis was also carried out via Lusas 13.6 code. Hashin failure criterion was preferred to determine both bearing strengths and failure modes. All in all, a good agreement is observed between experimental and numerical failure analyses.

Failure Response of Two Serial Bolted Aluminum Sandwich Composite Plates

The scope of this study is to examine the failure response in an aluminum—glass—epoxy sandwich composite plate with two serial circular holes, which is subjected to a traction force by two serial bolts. To determine the effects of joint geometry and applied/without preload moments on the bearing strength and failure mode, parametric studies were carried out experimentally. The end distance to diameter (E/D) and width to diameter (W/D) ratios in the specimens were designed from 1—5 to 2—5, respectively, whereas the distance between two serial holes and diameter ratio were fixed as 4. Besides, each type of specimen were tested under various applied preload moments as 2, 3, 4, 5 Nm and without preload moments (0 Nm). According to the experimental results, the bearing strength and maximum failure load generally increase by increasing E/D and W/D ratios and of applied preload moments. Besides, failure modes strictly affected these parameters.

Experimental failure analysis of two‐serial‐bolted composite plates

AbstractIn this study, a failure analysis of two‐serial‐bolted glass‐fiber‐reinforced epoxy composite plates was performed. To determine the influences of the joint geometry and stacking sequences on the bearing strength and failure mode, parametric studies were carried out experimentally. Three different geometrical parameters—the ratio of the edge distance to the hole diameter (E/D), the ratio of the plate width to the hole diameter (W/D), and the ratio of the distance between two holes to the hole diameter (K/D)—were considered. For this reason, the E/D, W/D, and K/D ratios were designed to range from 1 to 5, from 2 to 5, and from 3 to 5, respectively. Furthermore, the tests were performed with various preload moments (2, 3, 4, and 5 Nm) and without any preload moments (0 Nm). Because of the observed effect of the material parameters on the failure behavior, composite laminated plates were stacked in two different stacking sequences: [0°/0°/30°/30°]s and [0°/0°/45°/45°]s. The experimental results indicated that the failure response of the two‐serial‐bolted joints were strictly affected by the material parameters, geometrical parameters, and values of the applied preload moments. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Experimental failure analysis of bolted joints in moisture‐ and temperature‐induced composite laminates under preload

AbstractIn this study, an experimental investigation was carried out in a bolted glass fiber‐reinforced laminate under preload moments. The stacking sequence at the composite laminate was chosen as [90°/0°/45°/−30°]s. The preload moments were selected as 2, 4, and 6 Nm, in order to compare the influence of preload moments on failure modes and strengths. Some specimens were subjected to hot pure water at 70°C for 7 days. The bearing strength in this case was measured again under the same preload moments of 2, 4, and 6 Nm. It is found that the bearing strength of the specimen waited in hot water was 5.4% smaller than that of the specimen in dry condition. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers

The bearing strength and failure behavior of bolted e-glass/epoxy composite joints

An experimental study was carried out to investigate the failure strength of a pinned-joint E-glass/epoxy composite plate. The main objective was to examine the influence of the preload moment, the edge distance to the pin diameter ratio, and the specimen width to pin diameter ratio on the strength. The load-carrying capacity of the pin-loaded hole could be changed by varying the specimen geometry and the preload moment. Guidelines for effective geometrical configurations and the preload moment for the mechanically pin-connected E-glass/epoxy composite plate were specified based on the ultimate bearing strength.

Failure Analysis of Bolted Aluminum Sandwich Composite Plates under Compressive Preload

The aim of this study is to examine the failure load and failure mode in an aluminum— glass-epoxy sandwich composite plate fastened mechanically by a bolt and washers on a circular hole under a preload exerted by a moment. Parametric studies were performed by experiments to find out the effects of joint geometry and preload moment on the failure strength and failure mode. The preload moments chosen (M) were 0, 3 and 6 Nm while the end distance to hole diameter (E/D) and width to diameter (W/D) ratios were chosen as 1—5 and 2—5, respectively. It is concluded from these experiments that the failure load increases with the increase of M, E/D and W/D. When M, E/D and W/D ratios reach 3—6, 2—5 and 5 Nm, full bearing strengths occur, respectively. When E/D = 1 for all the widths and preload moments, the shear-out failure mode is observed. The mixed modes, especially bearing and net-tension, are observed for E/D and W/D equal to 2—5 and 3—4, respectively. The preload moments increase the failure strengths of the composite laminate.