Rate-dependent shear deformation of ductile acrylic adhesive and its constitutive modelling

2004 ◽  
Vol 218 (6) ◽  
pp. 623-629 ◽  
Author(s):  
M Takiguchi ◽  
S Izumi ◽  
F Yoshida
Keyword(s):  
Flow Stress ◽  
Stress Relaxation ◽  
Early Stage ◽  
Deformation Behaviour ◽  
Constitutive Modelling ◽  
Shear Tests ◽  
Adhesive Resin ◽  
Acrylic Adhesive ◽  
Rate Dependent ◽  
Lap Shear

Recently, new types of structural adhesive with high ductility, as well as high strength, have been developed and put on the market. Such high ductile adhesives usually have strong rate sensitivity in their flow stress. In order to investigate the rate-dependent deformation behaviour of an acrylic adhesive, tensile lap shear tests were performed at various crosshead speeds at room temperature. Stress relaxation tests were also performed. In the tensile lap shear tests, it was found that the shear flow stress of the adhesive resin increased remarkably with increasing shearing speed. In the stress relaxation tests, the stress decreased rapidly at the early stage, and it gradually approached an asymptotic stress value. In order to describe such rate-dependent deformation characteristics of adhesive resin, a viscoplastic constitutive model is presented in this paper. The shear stress-strain responses, as well as stress relaxation behaviour, predicted by the present model agree well with the corresponding experimental results.

scholarly journals Viscoplastic Behavior of Acrylic Adhesive in Butt-Joint at Various Temperatures under Complex Loading : Experimentation and Modelling

2007 ◽  
Vol 340-341 ◽  
pp. 1485-1490 ◽  
Author(s):  
Tetsuya Yoshida ◽  
Takayuki Oishi ◽  
Michihiro Takiguchi ◽  
Fusahito Yoshida
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Axial Stress ◽  
Complex Loading ◽  
Butt Joint ◽  
Adhesively Bonded ◽  
Stress Strain ◽  
Acrylic Adhesive ◽  
Strain Behavior ◽  
Lap Shear

The effects of temperature and strain rate on flow stress of a highly ductile acrylic adhesive were investigated by performing tensile lap shear experiments on an adhesively bonded single-lap joint, as well as torsion experiments on a tubular butt-joint at temperatures ranging from 10 to 40oC at various shear strain rates. The flow stress decreases considerably with decreasing strain rate and with temperature rise. The stress-strain responses under multi-axial stress conditions were also examined by performing combined tension-torsion experiments on the butt-joint. A constitutive model of temperature-dependent elasto-viscoplasticity that describes multi-axial stress-strain behavior of the adhesive is presented.

scholarly journals Clinching of Thermoplastic Composites and Metals—A Comparison of Three Novel Joining Technologies

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2286
Author(s):  
Benjamin Gröger ◽  
Juliane Troschitz ◽  
Julian Vorderbrüggen ◽  
Christian Vogel ◽  
Robert Kupfer ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Composite Material ◽  
Process Design ◽  
Failure Mechanisms ◽  
Thermoplastic Composites ◽  
Material Structure ◽  
Shear Tests ◽  
Load Bearing ◽  
Lap Shear ◽  
Resultant Material

Clinching continuous fibre reinforced thermoplastic composites and metals is challenging due to the low ductility of the composite material. Therefore, a number of novel clinching technologies has been developed specifically for these material combinations. A systematic overview of these advanced clinching methods is given in the present paper. With a focus on process design, three selected clinching methods suitable for different joining tasks are described in detail. The clinching processes including equipment and tools, observed process phenomena and the resultant material structure are compared. Process phenomena during joining are explained in general and compared using computed tomography and micrograph images for each process. In addition the load bearing behaviour and the corresponding failure mechanisms are investigated by means of single-lap shear tests. Finally, the new joining technologies are discussed regarding application relevant criteria.

A Modified Peric Model for Al-Mg Alloy Sheet with Rate-Independent Initial Yield Stress at Warm Temperatures

2019 ◽  
Vol 287 ◽  
pp. 3-7
Author(s):  
Yong Zhang ◽  
Qing Zhang ◽  
Yuan Tao Sun ◽  
Xian Rong Qin
Keyword(s):  
Flow Stress ◽  
Plastic Strain ◽  
Strain Rate ◽  
Yield Stress ◽  
Constitutive Models ◽  
Mg Alloy ◽  
Initial Yield Stress ◽  
Initial Yield ◽  
Rate Dependent ◽  
Dependent Flow

The constitutive modeling of aluminum alloy under warm forming conditions generally considers the influence of temperature and strain rate. It has been shown by published flow stress curves of Al-Mg alloy that there is nearly no effect of strain rate on initial yield stress at various temperatures. However, most constitutive models ignored this phenomenon and may lead to inaccurate description. In order to capture the rate-independent initial yield stress, Peric model is modified via introducing plastic strain to multiply the strain rate, for eliminating the effect of strain rate when the plastic strain is zero. Other constitutive models including the Wagoner, modified Hockett–Sherby and Peric are also considered and compared. The results show that the modified Peric model could not only describe the temperature-and rate-dependent flow stress, but also capture the rate-independent initial yield stress, while the Wagoner, modified Hockett–Sherby and Peric model can only describe the temperature-and rate-dependent flow stress. Moreover, the modified Peric model could obtain proper static yield stress more naturally, and this property may have potential applications in rate-dependent simulations.

scholarly journals Constitutive Modelling of Polylactic Acid at Large Deformation Using Multiaxial Strains

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2967
Author(s):  
John Sweeney ◽  
Paul Spencer ◽  
Glen Thompson ◽  
David Barker ◽  
Phil Coates
Keyword(s):  
Steady State ◽  
Stress Relaxation ◽  
Strain Hardening ◽  
Small Strain ◽  
Limited Range ◽  
Constitutive Modelling ◽  
True Stress ◽  
Final Strain ◽  
Transverse Stresses

Sheet specimens of a PLLA-based polymer have been extended at a temperature near to the glass transition in both uniaxial and planar tension, with stress relaxation observed for some time after reaching the final strain. Both axial and transverse stresses were recorded in the planar experiments. In all cases during loading, yielding at small strain was followed by a drop in true stress and then strain hardening. This was followed by stress relaxation at constant strain, during which stress dropped to reach an effectively constant level. Stresses were modelled as steady state and transient components. Steady-state components were identified with the long-term stress in stress relaxation and associated with an elastic component of the model. Transient stresses were modelled using Eyring mechanisms. The greater part of the stress during strain hardening was associated with dissipative Eyring processes. The model was successful in predicting stresses in both uniaxial and planar extension over a limited range of strain rate.

Correlation of wear and work in dual pivoted jaw crusher tests

2018 ◽  
Vol 234 (3) ◽  
pp. 334-349
Author(s):  
Juuso Terva ◽  
Kati Valtonen ◽  
Pekka Siitonen ◽  
Veli-Tapani Kuokkala
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Mass Loss ◽  
Lower Amount ◽  
Jaw Crusher ◽  
Rate Dependent ◽  
Sliding Motion ◽  
The Relationship

A laboratory sized jaw crusher with uniform movement of the jaws, the dual pivoted jaw crusher, was used to determine the relationship between wear and work. Wear was concentrated on the jaw plates opposing each other and was measured as mass loss of the specimens. Work was measured directly from the force and displacement of the instrumented jaw, which allowed work to accumulate only from the actual crushing events. The tests were conducted with several jaw geometries and with two motional settings, where the relation of compressive and sliding motion between the jaws was varied. The tests showed that the relation between wear and work was constant in many of the tested cases. In certain tests with larger lateral and faster contact speed, wear occurred at relatively lower amounts of work. This behavior was more definite when the relation of wear and work was investigated using modified Archards wear equation. The results indicate that the lower amount of needed work could stem from the material reaching a dynamic situation, where the flow stress becomes increasingly strain-rate dependent.

Heterogeneous FE model for single lap shear tests on FRP reinforced masonry curved pillars with spike anchors

2020 ◽  
Vol 258 ◽  
pp. 119629 ◽  
Author(s):  
Elisa Bertolesi ◽  
Gabriele Milani ◽  
Mario Fagone ◽  
Tommaso Rotunno ◽  
Ernesto Grande
Keyword(s):  
Fe Model ◽  
Shear Tests ◽  
Lap Shear ◽  
Reinforced Masonry
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