scholarly journals Rigid and Flexible Double Shear Lap Adhesive Joint at Elevated Temperature—An Experimental Study

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2873
Author(s):  
Klaudia Śliwa-Wieczorek ◽  
Bogusław Zając
Keyword(s):  
Elevated Temperature ◽  
Adhesive Joint ◽  
Load Capacity ◽  
Structural Response ◽  
Adhesive Layer ◽  
Visual Assessment ◽  
Epoxy Adhesive ◽  
Shear Tests ◽  
Partial Load ◽  
The Impact

Double lap adhesive connections made of Sika® PS and Monolith EP2579-1 were studied experimentally in shear tests. The destructive shear tests were conducted under a quasi-static load at 20 °C and 80 °C. The aim was to study the impact of elevated temperature on the load capacity of the joint and make a comparative analysis of the results for two types of adhesives: polyurethane Sika® PS (flexible) and epoxy Monolit EP 2579-1 (rigid). The impact of adhesive layer thickness (t = 1, 2 and 4 mm) on the structural response of the joint was tested in two temperature ranges. A distinct impact of the temperature on the joint deformability was noticed. A visual assessment of the joint failure was performed and the initiation and form of failure was described. At 20 °C, the ultimate loading for epoxy adhesive joint depending on the joint thickness (t) was greater than for the polyurethane joint by, respectively, 282% for t = 1 mm, 88% for t = 2 mm and 279% for t = 4 mm. It was proved that the temperature increases to 80 °C in case of both adhesives reduces the mean destructive force in comparison with the measurements made at 20 °C. For the Sika® PS (PUR two-component polyurethane) adhesive, the greatest load capacity decrease was measured for the joint of thickness t = 2 mm (55%), and in case of the epoxy adhesive for the joint of thickness t = 4 mm (89%). It was found that after reaching the destructive force the flexible joints retain a partial load capacity contrary to the rigid joints.

scholarly journals Effect of incorrect mix ratio on strength of two component adhesive Butt-Joints tested at elevated temperature

2018 ◽  
Vol 244 ◽  
pp. 01019
Author(s):  
Jakub Szabelski
Keyword(s):  
Elevated Temperature ◽  
Material Properties ◽  
Mixed Type ◽  
Epoxy Adhesive ◽  
Future Research ◽  
Butt Joints ◽  
Adhesive Material ◽  
Epoxy Adhesives ◽  
Two Component ◽  
The Impact

The aim of this study was to determine the impact of the incorrect mix ratio on the strength of joints bonded with a commercial epoxy adhesive compo-sition. The performance of cold-cured as well as accelerated cured butt joints was monitored at elevated temperature conditions. The obtained data was subjected to statistical analysis to show the correlation between joint strength at high temperature and incorrect mix ratio. The degradation of adhesive material properties with increase of hardener ratio in adhesive material was observed, as well as the change in failure type from mixed type to clearly cohesive (for inadequate volume of harde-ner) or adhesive (for excessive amount of hardener). Surprisingly insufficiency of hardener doesn’t affect the strength of joint in such manner. General recommend-dation were drawn for the preparation of two-component epoxy adhesives for joints to be used in elevated temperature, particularly when uncertainty regarding the correct resin/hardener mix ratio and future research was planned.

Effect of Alkali on the Impact Toughness of Adhesively Bonded Joints

2012 ◽  
Vol 166-169 ◽  
pp. 1904-1907
Author(s):  
Min You ◽  
Chun Zhi Mei ◽  
Wen Jun Liu ◽  
Jing Rong Hu ◽  
Ling Wu
Keyword(s):  
Impact Toughness ◽  
Moisture Absorption ◽  
Adhesive Layer ◽  
Epoxy Adhesive ◽  
Alkali Solution ◽  
Lap Joint ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Single Lap Joint ◽  
The Impact

The effect of the temperature and immersed time of the alkali solution on the impact toughness of the adhesively bonded steel single lap joint under impact loading is studied using the experimental method. The results obtained show that the impact toughness of the specimen increased when the immersed time increased then it decreased as it beyond 3 days. When the immersed time is longer than 72 h, the higher the temperature is, the lower the impact toughness of the joint. The moisture absorption of the adhesive layer with the immersed time was also investigated and it was found that there is a relationship to the impact toughness of the adhesively bonded single lap joint. The epoxy adhesive layer was analyzed with FT-IR and it was found that the hydroxyl enhanced and bonding strength may increase after 72 h immersed in alkali solution.

Long adhesive joints in façade applications exposed to wind suction

2020 ◽  
Vol 234 (5) ◽  
pp. 488-498
Author(s):  
B Nečasová ◽  
P Liška ◽  
J Šlanhof ◽  
P Sedlák ◽  
V Motyčka
Keyword(s):  
Adhesive Joint ◽  
Failure Load ◽  
Structural Response ◽  
Thick Layer ◽  
High Strength ◽  
Adhesive Joints ◽  
Maximum Pressure ◽  
Mechanical Joint ◽  
Test Assembly ◽  
The Impact

This paper provides an insight into the investigation of long thick-layer adhesive façade joint resistance to negative pressure loads, i.e. wind suction. The real structural response to wind actions was simulated with reference to ETAG 034. Each specimen represented a reference façade section. The experiment focused on four different adhesive systems with flexible high strength 1-K polyurethanes and 1-K modified silyl polymers. Several variants of the test assemblies were tested: 1) a test assembly with an adhesive joint when a) the manufacturers’ application instructions for the system were followed and b) the instructions were violated; 2) a test assembly with a mechanical joint. These variants made it possible to compare the properties of both fastening methods, and moreover, to assess the impact of the mounting tape on the properties of the adhesive joint. The comparison of adhesive joints and a mechanical joint proved the greater structural stiffness and stress resistance of bonded assemblies. Monitoring showed that a local failure of the fastening element between the load-bearing frame and supporting structure caused the failure of the bonded assemblies, whereas the specimen with mechanically attached cladding failed due to pull-through of the fasteners. The average failure load of the bonded assembly was 10.88 kPa. In contrast, the failure load of the segment with mechanical fasteners was 10.12 kPa. Even though the difference in maximum pressure loads was only around 7%, the recorded values clearly demonstrate that the weakest part of the whole façade system is the mechanical joint, not the bonded one. Furthermore, the comparison of the results for segments with and without mounting tape showed that tape can have a major impact on the bond strength, since in case of the test specimens without mounting tape, the recorded failure load was a maximum of 30% higher.

scholarly journals Comparative Shear Tests of Bolt Rods Under Static and Dynamic Loading

2020 ◽  
Vol 42 (2) ◽  
pp. 151-167
Author(s):  
Andrzej Pytlik
Keyword(s):  
Impact Loading ◽  
Load Capacity ◽  
Assessment Process ◽  
Shear Tests ◽  
Dynamic Impact ◽  
Similar Work ◽  
Mathematical Relationships ◽  
The Impact ◽  
Dynamic Impact Loading ◽  
Single Shear

AbstractThis article presents the methodology and results of single shear tests of bolt rods under dynamic impact loading generated by means of a drop hammer. Comparative analysis was also performed for bolt rod load capacity, stress and shear work under static and dynamic (impact) loading. The developed method of single shear testing of bolt rods under impact loading makes it possible to obtain repeatable test results concerning maximum bolt rod shearing force, shear stress and shear work values.Comparative shear tests of four types of bolt rods under static and impact loading showed that the APB-type bolt rods made of AP770 steel, which was characterised by having the highest strength, exhibited the greatest shear work. AM22-type bolt rods exhibited a very similar work value. Though the AM22-type bolt rods made of A500sh steel demonstrated lower strength than the APB-type bolts, as well as a smaller diameter and cross section, they dissipated the impact energy better thanks to their higher plasticity. This could indicate the direction of optimisation for bolt rods in order to increase their impact strength.Mathematical relationships were also formulated for selected tests, describing the real single shear courses F d =f(t) of bolts under impact loading. The obtained relationships could be applied in the load assessment process of bolt rods intended for use under roof caving, tremor and rock burst conditions.

Study of Adhesive Curing Pressure in Process of Ferrite Phase Shifter

2013 ◽  
Vol 842 ◽  
pp. 271-274 ◽  
Author(s):  
Qing Li ◽  
Gui Cui Fu ◽  
Bo Wan
Keyword(s):  
Adhesive Joint ◽  
Phase Shifter ◽  
Adhesive Layer ◽  
Epoxy Adhesive ◽  
Ferrite Phase ◽  
Pass Rate ◽  
Real Time Control ◽  
Cure Reaction ◽  
Time Control ◽  
Curing Pressure

The adhesive cure reaction in manufacture of ferrite phase shifter is studied. Strength of epoxy adhesive joint has been tested in process experiments. Mathematical model is fitted to describe the relationship between the strength of adhesive joint and curing pressure, and an appropriate curing pressure is obtained through sensitivity analysis. The real-time control scheme of process parameters is carried out to improve the first pass rate, which is influenced by void defects in the adhesive layer.

Investigation of Workpiece Distortion During the Photopolymerization of a PAAW Joint

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Kristopher R. Doll ◽  
Edward C. De Meter
Keyword(s):  
Residual Stresses ◽  
Adhesive Joint ◽  
Load Capacity ◽  
Tensile Force ◽  
Empirical Models ◽  
Thickness Reduction ◽  
Joint Thickness ◽  
A Value ◽  
Tensile Forces ◽  
The Impact

As a workpiece is bonded to a photo-activated adhesive workholding (PAAW) fixture, the adhesive shrinks during photopolymerization. This leads to the buildup of residual stresses that may distort the workpiece or reduce the external load capacity of the adhesive joints. This research quantifies the impact of adhesive shrinkage on fractional thickness reduction and residual tensile force for a commercially available adhesive and gripper. These variables are quantified for typical ranges of adhesive joint thickness and workpiece interface stiffness. Empirical models are presented for relating these variables. This research reveals that once photopolymerization ceases, workpiece distortion and residual stresses are permanent, and are not diminished by adhesive stress relaxation. It also reveals that the fractional thickness reduction of a PAAW joint can range from close to zero to a value equivalent to the fractional volumetric shrinkage of the adhesive. Furthermore, it decreases with increasing workpiece interface stiffness and increasing adhesive joint thickness following a power law relationship. It is believed that necking within the adhesive joint has a significant influence on this relationship. For stiff workpiece interfaces, residual tensile forces can grow larger than 25% of the tensile break strength of an adhesive joint formed without restraint.

Influence of the distribution of the shear walls on the seismic response of the buildings

2020 ◽  
Vol 15 (1) ◽  
pp. 37-44
Author(s):  
El Mehdi Echebba ◽  
Hasnae Boubel ◽  
Oumnia Elmrabet ◽  
Mohamed Rougui
Keyword(s):  
Structural Analysis ◽  
Seismic Response ◽  
Natural Frequency ◽  
Structural Design ◽  
Structural Response ◽  
Shear Walls ◽  
Structural Elements ◽  
Analysis Software ◽  
Ansys Apdl ◽  
The Impact

Abstract In this paper, an evaluation was tried for the impact of structural design on structural response. Several situations are foreseen as the possibilities of changing the distribution of the structural elements (sails, columns, etc.), the width of the structure and the number of floors indicates the adapted type of bracing for a given structure by referring only to its Geometric dimensions. This was done by studying the effect of the technical design of the building on the natural frequency of the structure with the study of the influence of the distribution of the structural elements on the seismic response of the building, taking into account of the requirements of the Moroccan earthquake regulations 2000/2011 and using the ANSYS APDL and Robot Structural Analysis software.

scholarly journals Structural Response of a Single-Stage Centrifugal Compressor to Fluid-Induced Excitations at Low-Flow Operating Condition: Experimental and Numerical Study

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4292
Author(s):  
Kirill Kabalyk ◽  
Andrzej Jaeschke ◽  
Grzegorz Liśkiewicz ◽  
Michał Kulak ◽  
Tomasz Szydłowski ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Numerical Study ◽  
Structural Response ◽  
Flow Coefficient ◽  
Low Flow ◽  
Dynamic Strain ◽  
Duct Acoustics ◽  
Numerical Noise ◽  
Partial Load ◽  
Compressor Impeller

The article describes an assessment of possible changes in constant fatigue life of a medium flow-coefficient centrifugal compressor impeller subject to operation at close-to-surge point. Some aspects of duct acoustics are additionally analyzed. The experimental measurements at partial load are presented and are primarily used for validation of unidirectionally coupled fluid-structural numerical model. The model is based on unsteady finite-volume fluid-flow simulations and on finite-element transient structural analysis. The validation is followed by the model implementation to replicate the industry-scale loads with reasonably higher rotational speed and suction pressure. The approach demonstrates satisfactory accuracy in prediction of stage performance and unsteady flow field in vaneless diffuser. The latter is deduced from signal analysis relying on continuous wavelet transformations. On the other hand, it is found that the aerodynamic incidence losses at close-to-surge point are underpredicted. The structural simulation generates considerable amounts of numerical noise, which has to be separated prior to evaluation of fluid-induced dynamic strain. The main source of disturbance is defined as a stationary region of static pressure drop caused by flow contraction at volute tongue and leading to first engine-order excitation in rotating frame of reference. Eventually, it is concluded that the amplitude of excitation is too low to lead to any additional fatigue.

Dependency of Machine Efficiency on the Thermal Behavior of Induction Machines

Machines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Svenja Kalt ◽  
Karl Ludwig Stolle ◽  
Philipp Neuhaus ◽  
Thomas Herrmann ◽  
Alexander Koch ◽  
...  
Keyword(s):  
Thermal Behavior ◽  
Electric Vehicles ◽  
Thermal Load ◽  
Load Capacity ◽  
Maximum Load ◽  
Induction Machines ◽  
Electric Machines ◽  
Model Parameters ◽  
Dynamic Operating ◽  
The Impact

The consideration of the thermal behavior of electric machines is becoming increasingly important in the machine design for electric vehicles due to the adaptation to more dynamic operating points compared to stationary applications. Whereas, the dependency of machine efficiency on thermal behavior is caused due to the impact of temperature on the resulting loss types. This leads to a shift of efficiency areas in the efficiency diagram of electric machines and has a significant impact on the maximum load capability and an impact on the cycle efficiency during operation, resulting in a reduction in the overall range of the electric vehicle. Therefore, this article aims at analyzing the thermal load limits of induction machines in regard to actual operation using measured driving data of battery electric vehicles. For this, a thermal model is implemented using MATLAB® and investigations to the sensitivity of model parameters as well as analysis of the continuous load capacity, thermal load and efficiency in driving cycles under changing boundary conditions are conducted.

The Experiments for the Impact of Temperature on the Grinding Rate about Zhao Tong Bauxite

2013 ◽  
Vol 734-737 ◽  
pp. 1119-1123
Author(s):  
Qing Hong Wang ◽  
Gu Zhang Zhuang ◽  
Chun Mei Wang
Keyword(s):  
Elevated Temperature ◽  
Grinding Temperature ◽  
The Impact ◽  
Slurry Viscosity

The viscosity of Pulp will affect the grinding rate directly, Elevated temperature, the slurry viscosity reduced. In order to study the effect on the grinding rate of temperature, we did the experiment by only changing the temperature, and three groups of contrast test was carried out. The results show that the grinding rate is improved obviously, when the grinding temperature increases from 16 °C to 42 °C.

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