Apparent Young’s Modulus of the Adhesive in Numerical Modeling of Adhesive Joints

This article is an evaluation of the phenomena occurring in adhesive joints during curing and their consequences. Considering changes in the values of Young’s modulus distributed along the joint thickness, and potential changes in adhesive strength in the cured state, the use of a numerical model may make it possible to improve finite element simulation effects and bring their results closer to experimental data. The results of a tensile test of a double overlap adhesive joint sample, performed using an extensometer, are presented. This test allowed for the precise determination of the shear modulus G of the cured adhesive under experimental conditions. Then, on the basis of the research carried out so far, a numerical model was built, taking the differences observed in the properties of the joint material into account. The stress distribution in a three-zone adhesive joint was analyzed in comparison to the standard numerical model in which the adhesive in the joint was treated as isotropic. It is proposed that a joint model with three-zones, differing in the Young’s modulus values, is more accurate for mapping the experimental results.

Results of treatment of arthrosis of the acromial-clavicular joint in patients with partial rupture of the supraspinatus muscle tendon

Introduction: Very often, partial tear tendons of the superficial shoulder muscle are combined with arthrosis of the clavicular-acromial joint. This is due to violations of the shoulder-patch rhythm, which in turn leads to a chronic overload of the clavicular-acromial joint and the progression of arthrosis in this joint. Aim: The purpose of the study is to improve the results of treatment of patients with injuries of the supraspinatus tendon against the background of deforming arthrosis of the clavicular-acromial joint. Material and methods: For the study a clinical group was assembled, which consisted of 84 patients with injuries of the tendon of the supraspinatus and deforming arthrosis of the clavicular-acromial joint 3–4 parts. All patients, depending on the treatment, were divided into two groups. Results and discussion: The consequences and influence of the arthrosis of the clavicular-acromial joint were determined. Movements of the joint were examined. The shoulder joint function was under control in the post-surgery period, which provided particular results and conclusions according to the comparative analysis of the two groups. Conclusions: Based on the provided results, it can be concluded that deforming arthrosis of the clavicular acromial joint can cause contracture in the shoulder joint in patients after the suture of the tendon of the abdominal muscle.

Investigation of the Restored Joint for Aluminum Alloy

In recent years, the mechanical clinching method plays an increasingly important role in the building of thin-walled structures. The clinched joint can be employed to join the lightweight materials. Compared with other joining methods, the clinched joint has better mechanical behavior. However, the clinched joint may be deformed during use when it bears a high shear force. In this research, a process to join aluminum alloy and restore deformed joint was proposed and investigated. The clinched joint was deformed in the deforming process. Then, a customized rivet and two flat restoring tools were utilized for restoring the deformed joint to join aluminum alloy. Different restoring forces such as 45, 40, 35, 30, 25, and 20 kN were employed to produce diverse restored joints. Some shearing tests on the restored joint were utilized for understanding joint material flow, mode of failure, thickness of neck, shear strength, and absorption of energy. The thickness of neck can be increased in restoring process, which contributes to improve the shear strength. The rivet embedded in a pit also helps restored joint bear shear force, so all of the restored joints have higher absorption of energy and shear strength than the clinched joints. The restoring process effectively restores the deformed joint to obtain better mechanical behavior.

Chondroplasty Efficacy of Bone Matrix

Aim To study the chondroplasty efficacy of the bone matrix obtained using an original technology in restoring cartilage defect of the knee joint. Material and Methods Marginal defects were modeled on the surface of the distal end of the femur in 40 adult male Wistar rats. The bone matrix obtained using an original technology was implanted in the damaged area in animals of the experimental group. Material was investigated by means of light microscopy, transmission and scanning electron microscopy, and electron probe X-ray microanalysis. Results It was found that the bone matrix implanted did not cause an immune rejection reaction, activated reparative chondrogenesis for a prolonged period. In the area of articular cartilage lesion, the regenerate acquiring cellular and histochemical characteristics of the hyaline cartilage tissue was formed. The chondroinductive properties for the bone matrix were ensured by localized growth factors and morphogenetic proteins released during osteoclastic resorption. Conclusion The application of the bone matrix as a stimulator of chondrogenesis is theoretically reasonable and has a good perspective in treatment of damages and diseases of the articular cartilage.

Failure Evaluation of Hybrid Joints using Taguchi Method

The structural joints for various applications like automobile, aero planes, ships etc. used mechanical fasteners or adhesives for joining purpose. The mechanical fastener increases the weight of the joints and the adhesives have a catastrophic failure nature. So to reduce the overall weight of the joint and avoid the catastrophic failure of the joint, Hybrid Joint, which is the combination of the two methods (Bolts and adhesives) is used. The Analytical Hierarchal process (AHP) is used to select the parameters that affect the performance of the joint. The selected parameters were bolt size, tightening torque, bolt hole clearance, adhesive type, adhesive thickness, overlap length and joint material and the response variables were failure load and displacement The optimum parameters were selected by using Taguchi analysis with L27 orthogonal array experimental design. The significant parameters were found to be Adhesive type, Adhesive thickness and Joint Material.