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The purpose of this paper is to study the effect of intermetallic compound (IMC) layer thickness on the shear strength of surface-mount component 1206 chip resistor solder joints.

To evaluate the shear strength and IMC thickness of the 1206 chip resistor solder joints, the test vehicles were conventionally reflowed for 480 seconds at a peak temperature of 240°C at different isothermal ageing times of 100, 200 and 300 hours. A cross-sectional study was conducted on the reflowed and aged 1206 chip resistor solder joints. The shear strength of the solder joints aged at 100, 200 and 300 hours was measured using a shear tester (Dage-4000PXY bond tester).

It was found that the growth of IMC layer thickness increases as the ageing time increases at a constant temperature of 175°C, which resulted in a reduction of solder joint strength due to its brittle nature. It was also found that the shear strength of the reflowed 1206 chip resistor solder joint was higher than the aged joints. Moreover, it was revealed that the shear strength of the 1206 resistor solder joints aged at 100, 200 and 300 hours was influenced by the ageing reaction times. The results also indicate that an increase in ageing time and temperature does not have much influence on the formation and growth of Kirkendall voids.

A proper correlation between shear strength and fracture mode is required.

The IMC thickness can be used to predict the shear strength of the component/printed circuit board pad solder joint.

The shear strength of the 1206 chip resistor solder joint is a function of ageing time and temperature (°C). Therefore, it is vital to consider the shear strength of the surface-mount chip component in high-temperature electronics.

To review, analyze and present the effects of the contact‐fluid interfacial shear strength and contact‐fluid interfacial slippage and the critical importance of these effects in elastohydrodynamic lubrication (EHL).

The experimental and theoretical research results of the contact‐fluid interfacial shear strength and its caused contact‐fluid interfacial slippage in hydrodynamic lubrication and especially in EHL obtained in the past decades and progressed in recent years by the present author and by others are reviewed. Analysis and presentation are made on both the contact‐fluid interfacial shear strength versus fluid pressure curve for a given bulk fluid temperature in an isothermal EHL and the influence of the bulk fluid temperature on this curve.

It is very clearly and well understood from the present paper that the value of the contact‐fluid interfacial shear strength in the inlet zone in an EHL contact, i.e. at low EHL fluid film pressures is usually low and usually has rather a weak dependence on the EHL fluid film pressure. This proves the correctness of the EHL theories previously developed by the author based on the assumption of this low value and dependence on the EHL fluid film pressure of the contact‐fluid interfacial shear strength. It is also very clearly understood that the bulk fluid temperature usually has a strong influence on the value of the contact‐fluid interfacial shear strength in EHL and the increase of this temperature usually significantly reduces the value of the contact‐fluid interfacial shear strength in EHL.

A very useful material for the engineers who are engaged in the design of EHL on gears, cams and roller bearings, and for the tribology scientists who thrust efforts in studying EHL and mixed EHL both by theoretical modeling and by experiments.

A new and generalized mode of mixed EHL is originally proposed by incorporating the finding of a more realistic mode of the contact regimes in a practical mixed EHL based on the contact‐fluid interfacial shear strength and contact‐fluid interfacial slippage effects. This mode of mixed EHL should become the direction of the theoretical research of mixed EHL in the future.

This study aims to analyze the shear strength and fracture mechanism of full Cu-Sn IMCs joints with different Cu₃Sn proportion and joints with the conventional interfacial structure in electronic packaging.

The Cu-Sn IMCs joints with different Cu₃Sn proportion were fabricated through soldering Cu-6 μm Sn-Cu sandwich structure under the extended soldering time and suitable pressure. The joints of conventional interfacial structure were fabricated through soldering Cu-100 μm Sn-Cu sandwich structure. After the shear test was conducted, the fracture mechanism of different joints was studied through observing the cross-sectional fracture morphology and top-view fracture morphology of sheared joints.

The strength of joints with the conventional interfacial structure was 26.6 MPa, while the strength of full Cu-Sn IMCs joints with 46.7, 60.6, 76.7 and 100 per cent Cu₃Sn was, respectively, 33.5, 39.7, 45.7 and 57.9 MPa. The detailed reason for the strength of joints showing such regularity was proposed. For the joint of conventional interfacial structure, the microvoids accumulation fracture happened within the Sn solder. However, for the full Cu-Sn IMCs joint with 46.7 per cent Cu₃Sn, the cleavage fracture happened within the Cu6Sn5. As the Cu₃Sn proportion increased to 60.6 per cent, the inter-granular fracture, which resulted in the interfacial delamination of Cu₃Sn and Cu6Sn5, occurred along the Cu₃Sn/Cu6Sn5 interface, while the cleavage fracture happened within the Cu6Sn5. Then, with the Cu₃Sn proportion increasing to 76.7 per cent, the cleavage fracture happened within the Cu6Sn5, while the transgranular fracture happened within the Cu₃Sn. The inter-granular fracture, which led to the interfacial delamination of Cu₃Sn and Cu, happened along the Cu/Cu₃Sn interface. For the full Cu₃Sn joint, the cleavage fracture happened within the Cu₃Sn.

The shear strength and fracture mechanism of full Cu-Sn IMCs joints was systematically studied. A direct comparison regarding the shear strength and fracture mechanism between the full Cu-Sn IMCs joints and joints with the conventional interfacial structure was conducted.

Based on the mechanical model of typical shear tests, this study aims to propose the test principle and method of freshwater/seawater ice adhesion shear strength of carbon ceramic brake pads for amphibious aircraft, designs and builds the test equipment, prepares the freshwater/seawater ice samples and completes the tests.

This study examines the influence of the icing process, mechanism, temperature and freshwater/seawater on ice adhesion shear strength of carbon ceramic brake pads and puts forward a test method for the freshwater/seawater ice adhesion shear strength of amphibious aircraft brake pads.

The obtained results examine the influence of the icing process, mechanism, temperature and freshwater/seawater on ice adhesion shear strength of carbon ceramic brake pads. The adhesion shear strength of frozen freshwater and of the seawater of Dalian, Qingdao, Fuzhou and Zhuhai on the surface of aircraft brake pads is measured at –10 to –50°C. It is found that the shear strength of freshwater increases first and then decreases with the decrease of temperature. The adhesion shear strength of seawater; however, increases mainly linear with the decrease of temperature.

The value of this paper is that the test method proposed and test results for the freshwater/seawater ice adhesion shear strength of amphibious aircraft brake pads provide technical support for the anti-icing design of amphibious aircraft brake devices.

This study aims to develop a bimodal nano-silver paste with improved mechanical property and reliability. Silicon carbide (SiC) particles coated with Ag were introduced in nano-silver paste to improve bonding strength between SiC and Ag particles and enhance high-temperature stability of bimodal nano-silver paste. The effect of sintering parameters such as sintering temperature, sintering time and the proportion of SiC particles on mechanical property and reliability of sintered bimodal nano-silver structure were investigated.

Sandwich structures consist of dummy chips and copper substrates with nickel and silver coating bonded by nano-silver paste were designed for shear testing. Shear strength testing was conducted to study the influence of SiC particles proportions on the mechanical property of sintered nano-silver joints. The reliability of the bimodal nano-silver paste was evaluated experimentally by means of shear test for samples subjected to thermal aging test at 150°C and humidity and temperature testing at 85°C and 85 per cent RH, respectively.

Shear strength was enhanced obviously with the increase of sintering temperature and sintering time. The maximum shear strength was achieved for nano-silver paste sintered at 260°C for 10 min. There was a negative correlation between the proportion of SiC particles and shear strength. After thermal aging testing and humidity and temperature testing for 240 h, the shear strength decreased a little. High-temperature stability and high-hydrothermal stability were improved by the addition of SiC particles.

Submicron-scale SiC particles coated with Ag were used as alternative materials to replace part of nano-silver particles to prepare bimodal nano-silver paste due to its high thermal conductivity and excellent mechanical property.

The purpose of this paper is to study the variation of the mechanical strength and failure modes of solder balls with reducing diameters under conditions of multiple reflows.

The solder balls with diameters from 250 to 760 µm were mounted on the copper-clad laminate by 1-5 reflows. The strength of the solder balls was tested by the single ball shear test and pull test, respectively. The failure modes of tested samples were identified by combing morphologies of fracture surfaces and force-displacement curves. The stresses were revealed and the failure explanations were assisted by the finite element analysis for the shear test of single solder ball.

The average strength of a smaller solder ball (e.g. 250 µm in diameter) is higher than that of a larger one (e.g. 760 µm in diameter). The strength of smaller solder balls is more highly variable with multiple reflows than larger diameters balls, where the strength increased mostly with the number of reflows. According to load-displacement curves or fracture surface morphologies, the failure modes of solder ball in the shear and pull tests can be categorized into three kinds.

The strength of solder balls will not deteriorate when the diameter of solder ball is decreased with a reflow, but a smaller solder ball has a higher failure risk after multiple reflows. The failure modes for shear and pull tests can be identified quickly by the combination of force-displacement curves and the morphologies of fracture surfaces.

The stone dust column was used to strengthen the sample and had a significant effect on improving the shear strength of the kaolin clay. The application of stone columns, which can improve the overall carrying capacity of soft clay as well as lessen the settlement of buildings built on it, is among the most widespread ground improvement techniques throughout the globe. The performance of foundation beds is enhanced by their stiffness values and higher strength, which could withstand more of the load applied. Stone dust is a wonderful source containing micronutrients for soil, particularly those derived from basalt, volcanic rock, granite and other related rocks. The aim of this paper is to evaluate the properties of soft clay reinforced with encapsulated stone dust columns to remediate problematic soil and obtain a more affordable and environmentally friendly way than using other materials.

In this study, the treated kaolin sample's shear strength was measured using the unconfined compression test (UCT). 28 batches of soil samples total, 12 batches of single stone dust columns measuring 10 mm in diameter and 12 batches of single stone dust columns measuring 16 mm in diameter. Four batches of control samples are also included. At heights of 60 mm, 80 mm and 100 mm, respectively, various stone dust column diameters were assessed. The real soil sample has a diameter of 50 mm and a height of 100 mm.

Test results show when kaolin is implanted with a single encased stone dust column that has an area replacement ratio of 10.24% and penetration ratios of 0.6, 0.8 and 1.0, the shear strength increase is 51.75%, 74.5% and 49.20%. The equivalent shear strength increases are 48.50%, 68.50% and 43.50% for soft soil treated with a 12.00% area replacement ratio and 0.6, 0.8 and 1.0 penetration ratios.

This study shows a comparison of how sample types affect shear strength. Also, this article provides argumentation behind the variation of soil strength obtained from different test types and gives recommendations for appropriate test methods for soft soil.

Recycled concrete is an economical and environmentally friendly green material. The shear performance of recycled concrete load-bearing masonry is studied, which is great of significance for its promotion and application and also has great significance for the sustainable development of energy materials.

In total, 30 new load-bearing block masonry samples of self-insulating recycled concrete are subjected to pure shear tests, and 42 samples are tested subjected to shear-compression composite shear tests. According to the axial design compression ratio, the test is separated into seven working conditions (0.1–0.8).

According to the test results, the recommended formula for the average shear strength along the joint section of recycled concrete block masonry is given, which can be used as a reference for engineering design. The measured shear-compression correlation curves of recycled concrete block masonry are drawn, and the proposed limits of three shear-compression failure characteristics are given. The recommended formula for the average shear strength of masonry under the theory of shear-friction with variable friction coefficient is given, providing a valuable reference for the formulation of relevant specifications and practical engineering design.

Simulated elastoplastic analysis and finite element modeling on the specimens are performed to verify the test results.

Material properties, such as shear and compressive strength of masonry, have a crucial impact on the seismic analysis results of masonry structures. Considering that most of the historical buildings are masonry structures, the damage caused by obtaining shear strengths with known methods exceeds acceptable limits. Instead of traditional shear strength index tests, this paper presents a test technique that has been developed which causes less damage to the structure, to obtain mechanical properties in masonry structures.

A new approach to shear testing and a test probe has been developed to minimize the destructive effects of mechanical in situ testing on masonry structures. The comparison of the results obtained with reduced destruction level using the novel shear strength index test probe with those obtained from the traditional method is addressed. Masonry specimens were tested in the laboratory and in situ tests were carried out on 12 historical buildings.

Test results obtained from the proposed probe shear strength index test were consistent with the results obtained from the conventional shear strength test both at the laboratory setting and in situ. Although a large number of data is needed for the validation of a method, satisfactory agreement with the conventional shear strength index test method was obtained.

The authors believe that the proposed method would give the opportunity to collect more mechanical strength data with much less destruction. The experimental work in the laboratory and in situ tests and their comparisons are the supportive and original values of this research.

Seeks to study the dependence of the shear strength of a fluid on the fluid pressure and the bulk fluid temperature, respectively, theoretically for given bulk fluid temperatures and fluid pressures in the whole ranges of fluid pressure and bulk fluid temperature.

The analyses are, respectively, carried out with emphasis on the dependence of the shear strength of a fluid in liquid state, i.e. at low pressures on the fluid pressure and the bulk fluid temperature for given bulk fluid temperatures and fluid pressures based on the theory of the compression of the fluid by the pressurization of the fluid.

The fluid shear strength versus fluid pressure curve in the whole range of fluid pressure and the fluid shear strength versus bulk fluid temperature curve in the whole range of bulk fluid temperature, respectively, for a given bulk fluid temperature and a given fluid pressure are obtained. It is shown by this fluid shear strength versus fluid pressure curve that, for a given bulk fluid temperature, when the fluid is in liquid state, i.e. at low pressures, the value of the shear strength of the fluid is insensitive to the variation of the pressure of the fluid and is low: when the fluid is in solidification state, i.e. at medium and high but not extremely high pressures, the value of the shear strength of the fluid is the most sensitive to the variation of the pressure of the fluid and is very approximately linearly increased with the increase of the pressure of the fluid; when the fluid is in high solidification state, i.e. at extremely high pressures, the value of the shear strength of the fluid is insensitive to the variation of the pressure of the fluid and is the highest, i.e. approaches the value of the shear strength of the fluid in solid state.

Extends one's knowledge of the shear strength of a fluid in the while ranges of pressure and temperature.